Introduction

The concept of red cultural heritage originates from China and was first proposed in the People’s Daily [1]. Red industrial heritage, as a historical testament to the Communist Party of China’s leadership towards modernization and an important revolutionary cultural relic, exhibits unique epochal characteristics and profound cultural connotations. Initial studies primarily focused on defining and analyzing the concept of red cultural heritage [2]. Over time, academic research has expanded into broader areas, including the connotations, characteristics, values, types, and theoretical frameworks of red cultural heritage [3]. Scholars now recognize that red cultural heritage should not be limited to revolutionary bases; its research scope should extend to red tourism sites, historical sites, artifacts, revolutionary history, and other related areas [4]. Some scholars have also explored high-quality development pathways for red cultural resources and red tourism from the perspective of integrating culture with tourism. They emphasize the core role of red cultural heritage in inheriting and protecting the genetic heritage of red culture [5]. Additionally, they have proposed a four-dimensional framework for red cultural heritage resources, which includes “people, objects, events, and spirit.” On the practical level, some researchers have utilized digital technology to create audio-visual archives. This approach effectively addresses challenges in the conservation, restoration, and value dissemination of red cultural heritage. As a result, it ensures the long-term preservation and sustained utilization of these valuable cultural assets [6].

Current research on red cultural heritage mainly focuses on conceptual analysis, value function, and resource management, with fewer studies from the perspective of design studies. In order to address the research gap, this study introduces semiotics, Gestalt psychology, cognitive psychology, and semantics into the field of signage system design based on the concept of universal design, proposing a method for designing universal signage systems for red cultural heritage sites.

The Ruijin Soviet Republic, as the starting point of the Long March of the Chinese Workers’ and Peasants’ Red Army, is a historic land rich in red cultural heritage. The red cultural resources here not only constitute an essential chapter in the history of the Chinese revolution but also symbolize red culture, possessing immense historical and cultural value [7]. To further develop the revolutionary bases, designing appropriate signage systems for red cultural tourism sites has become a crucial public infrastructure supporting regional development. With an increasingly diverse visitor demographic to red tourism towns, particular attention needs to be paid to meeting the information acquisition needs of foreign visitors and groups with special needs. Based on the universal design principle of “designing for all,” Ruijin’s signage system aims to help both domestic and international tourists overcome language and cultural barriers to quickly obtain the necessary directional information. Such a universal signage system not only helps protect and promote the red cultural heritage of the Ruijin period but also enhances the public’s understanding and respect for this historical and cultural heritage, providing unique cultural experiences and educational value [8]. In this way, Ruijin’s red cultural heritage sites serve as places of historical education and inspire public patriotism and social responsibility, further promoting regional cultural and tourism development.

Literature review and research hypothesis

Universal signage system design

The concept of universal design was first proposed in the United States in 1985 by Ron Mace, a professor at North Carolina State University [9]. This design philosophy aimed to transition from traditional accessibility designs targeted at specific groups to a more comprehensive, all-inclusive approach. Signage systems, as crucial tools for acquiring environmental information, center around human-centered design, taking into account user characteristics [10]. Universal design is based on the principle of meeting the broad needs of all users, which aligns with the aims of signage system design [11]. In China, research on signage system design typically focuses on functionality and aesthetics, but exploration into universal signage systems remains limited. Especially in red cultural tourism areas, effectively integrating red graphics, colors, and fonts into designs is critical to conveying the spirit of red culture [12]. The signage systems at tourist sites are closely integrated with red culture, enhancing visitors’ understanding and appreciation of red culture through cultural elements such as revolutionary figures, historical events, and related sites [13].

Western countries have an earlier start in the research and application of signage systems, especially in thematic cultural tourism, where signage design has become increasingly sophisticated. The interaction between cultural heritage and tourists highlights the importance of protecting cultural heritage and enhancing the visibility of tourist sites [14]. To strengthen this interaction, some scholars suggest focusing on improvements in signage design. They recommend reinforcing the connection between signs and cultural symbols by using icons to visually represent these relationships. This approach highlights the central role of signage systems in cultural dissemination and enhances the visitor experience at heritage sites [15]. This study draws on universal design principles and applies them to the signage system design at the Ruijin Soviet Cultural Heritage Site. This approach considers the diverse needs of visitors from various nationalities, cultural backgrounds, age groups, and educational levels. By effectively conveying information and guiding visitors, the accessibility of Ruijin Soviet Cultural Heritage Site is improved [16], thereby promoting the understanding and dissemination of cultural heritage among all visitors.

Visual representation and perception of heritage

The visual representation of heritage is a form of historical reenactment [17] involving the encoding and decoding of visual information. By constructing the structural relationships of visual representation [18], cultural heritage is visually displayed [19]. Graphic symbols, as visual image tools [20], can transcend cultural and linguistic boundaries, enabling the rapid and accurate transmission of information through visual elements. These symbols not only have significant directional functions but also serve as a universal visual language [21]. In the visual representation of cultural heritage, graphic symbols are used to convey specific historical and cultural meanings. These symbols help convert three-dimensional spatial information into two-dimensional representations, effectively organizing and transmitting visual messages [22].

Gestalt psychology provides a theoretical framework for explaining human visual perception, emphasizing two key principles: the laws of perceptual organization and perceptual constancy [23]. The laws of perceptual organization explore how the human visual system organically organizes and perceives observed elements, involving principles such as proximity, similarity, and continuity, which highlight the tendency towards holistic cognition in visual perception [24]. Perceptual constancy suggests that despite changes in specific attributes, such as the size [25], posture [26], or external lighting conditions of an object, these changes do not affect the stability of overall perception. Therefore, the following hypotheses are proposed:

H1. The symbolic element modeling has a significant positive influence on perception.

H2. The representation of symbolic elements has a significant positive influence on perception.

H3. The comfort level of pattern recognition has a significant positive influence on perception.

Visual cognition of heritage

Vision is one of the key means by which humans perceive the external world, profoundly influencing our experience of the world [27]. In visual cognition of cultural and historical heritage, this perception is not just a sensory experience but also a complex cognitive activity [28]. From the cognitive psychology perspective, an individual’s visual cognition of heritage includes the intuitive perception of its visual features and the interpretation of the deep cultural and historical meanings these features represent [29]. Through visual cues, visitors can evoke memories and stimulate emotions, thereby forming personal understandings and emotional connections with the heritage [30]. In this process, cognitive mapping, symbolic understanding, and the use of cultural background knowledge play a decisive role in interpreting and experiencing heritage [31]. Thus, the visual cognition of heritage is not just a perception of physical attributes but a dynamic, interactive cognitive construction process that involves multidimensional interactions from sensory perception to deep cultural understanding [32]. The assessment of this cognitive process is based on the four core dimensions of semiotics: symbolic form, meaning, construction, and symbolic usage [33]. The form focuses on whether the shape of the symbol accurately reflects the key features of its represented object, which is the basis of symbol recognizability, determining its visual discernibility and effectiveness in conveying information [34]; the meaning refers to how the form indirectly expresses the relationship between the symbol object and its significance [35]; the construction involves the relationships between internal elements of the symbol [36]; and the usage focuses on the application and expression of the symbol, particularly how graphic symbols construct meaning in different environmental and cultural contexts [37]. Therefore, the following hypotheses are proposed:

H4. The familiarity of graphics has a significant positive influence on comprehensibility.

H5. The semantic distance of graphics has a significant positive influence on comprehensibility.

H6. The visual complexity of graphics has a significant positive influence on the comprehensibility.

H7. The rationality of graphic usage has a significant positive influence on comprehensibility.

Visual construction of heritage

The visual construction of heritage is the practice of translating the deep values and meanings of cultural heritage into visual symbols. This process involves behavior patterns, ideologies, and the expression of values [38]. In this process, semiotics provides crucial theoretical support for understanding and decoding symbols and their meanings. It examines how symbols are interpreted within specific cultural and social contexts and constructs a complex and layered visual network by analyzing the semantic properties of visual elements in conjunction with the cultural backgrounds and expected interpretations of the target audience [39]. This visual construction not only reflects the intuitive display of symbols but also deeply reveals the multidimensional factors of social culture. Deliberate construction of visual symbols at heritage sites enhances the interpretation of specific cultural meanings and historical contexts [40]. The visual representation of heritage is usually achieved through the visual perception of visitors, and due to differences in individual backgrounds, different visitors may interpret the same heritage elements differently. These individual differences ultimately affect their cognitive level of heritage [41]. Therefore, the effectiveness of a signage system largely depends on its ability to be visually perceived by diverse audiences. The assessment of the visual impact of heritage begins with the process of visual cognition [42], including the perception and understanding of graphic symbols. Tests of perception and comprehensibility, recognized as international assessment methods, are widely used globally [43]. Studies in visual psychology indicate that features such as the color, shape, size, and spatial arrangement of graphics significantly affect viewers’ attention distribution and information processing speed, thereby profoundly impacting the depth and accuracy of understanding. Thus, the following hypotheses are proposed:

H8. Perception has a significant positive influence on comprehensibility.

H9. Perception has a significant positive influence on visual cognition.

H10. Comprehensibility has a significant positive influence on visual cognition.

H11. Visual cognition has a significant positive influence on the design of universal signage systems.

Thus, the conceptual model and the proposed hypothesis are shown in Fig. 1.

Fig. 1
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Research model. A research model on the influencing factors of universal signage system design

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The establishment of digital visual resource library

Construction of digital resource element library

In red culture studies, metadata, which refers to data about data, is used to describe in detail the content, characteristics, and properties of data [44]. Red cultural heritage’s profound value primarily lies in documenting and organizing the events involved, related historical periods, geographical locations, and connections among participants. Based on this understanding, the existing heritage resources in Ruijin, a red metropolis, can be categorized into two main types: physical data and non-physical data. Physical data includes six types: historical events, red relics, red artifacts, red art, revolutionary figures, and photographic images. Non-physical data includes red slogans and red spirit.

This database is based on the red cultural data from the period of the Ruijin Soviet Republic [45], referencing international metadata standards such as CIDOC CRM and incorporating domestic standards like “Regulations on Cultural Relics Archives,” “Regulations on the Registration of Museum Collection Relics,” and “Application Standards for Metadata Description of Cultural Relics.” A metadata standard system was designed, which not only reflects the diverse types of red culture from the Ruijin Soviet period but also provides a methodological foundation for constructing a universal national image ontology. Additionally, by referencing practices and developments in metadata classification from other academic fields, the metadata structure is divided into three levels: “Cultural Type,” “Data Attribute,” and “Data Type,” with eight items each in cultural and description types. Description types are categorized into number, name, time, geography, humanity, material, type, and completeness. See Table 1.

Table 1 Metadata structure of Ruijin Soviet cultural resources
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Visual mapping of digital resources

When dealing with the physical data and non-physical data within a data repository, visual transformation is achieved through digital means. For physical data, the emphasis is on capturing and re-presenting their physical attributes. In contrast, symbolic methods are employed for non-physical data to showcase their conceptual features and cultural values [46], thereby constructing a digital visual resource library. See Fig. 2.

Fig. 2
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Digital visual resource library. Visual mapping of digital resources

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Visual transformation of physical data

The visual transformation of physical data is based on OpenCV, an open-source computer vision library [47]. Utilizing its refined and efficient algorithmic processing, it can identify and extract the physical form features from physical data, implementing a universal algorithm for image processing and visual transformation [48]. This provides an effective and accurate digital visual solution for the material form characteristics in the database. The specific process is as follows:

(1) Threshold segmentation

Threshold segmentation simplifies the image into a binary format, making it easier to analyze [49]. By reducing the original image's information, it highlights key features and minimizes errors from uneven color distribution. The image is then converted to grayscale by calculating the weighted average of the red, green, and blue (RGB) pixel values. This conversion facilitates further processing, analysis, and recognition.

(2) Gaussian blur

Gaussian blur is used to reduce image noise and detail [50], enhancing the visual effect of the image. By performing a convolution operation on the input grayscale image, a Gaussian function is used to calculate the weighted average of each pixel and its surrounding pixels, blurring noise and fine details in the image [51]. This reduces the impact of noise on image quality, making the subsequent image processing more accurate and stable.

(3) Edge detection

Edge detection primarily focuses on areas in an image with significant brightness changes, aiming to identify all possible boundary lines in the image [52]. The Canny algorithm is known for its precise edge localization and fast processing speed. Using the Canny algorithm to perform edge recognition and digital extraction of material form features in the image library [53] allows for the rapid and accurate capture of image edges.

(4) Contour recognition

Contour recognition is performed further based on edge detection [54]. OpenCV uses the findContours function to detect contours from the binary image. By analyzing the edge points identified in the edge detection phase, it connects broken edge fragments or excludes erroneous edges that do not match specific shape features, ultimately forming complete object contour lines [55].

(5) Symbol optimization

The contour lines obtained from contour recognition are filled with color and optimized in form, such as meticulous adjustments to the graphic contours and the selection and application of colors to increase visual appeal [56] and the efficiency of information transmission [57]. Through this optimization, line sketches are endowed with richer visual dimensions and more defined symbolic meanings, enabling them to effectively carry and transmit specific information within the visual information network.

Visual transformation of non-physical data

Non-physical data typically reflects abstract concepts and ideas, and delving into the underlying factors of these data requires comprehensive research, observation, and analysis across multiple dimensions, such as society, culture, and values [58]. This includes conducting detailed interviews with local residents, cultural practitioners, and history experts [59], in order to profoundly understand the deep meanings contained within red culture. These abstract concepts can then be transformed into visual graphic symbols.

Construction of visual information network

Constructing a visual information network relies on graphic and image technologies, which effectively establish, convey, and display the relationships between heritage resources [60]. The digital resource repository of the Ruijin Soviet mainly consists of unstructured data formed by text and images. To effectively utilize this data, entity recognition and the mining of associations between entities are essential [61]. This process creates a series of “entity-relationship-entity” triplet structures, which help build a clear and logically coherent visual information network [62]. To process these unstructured data, a deep learning model based on the Transformer architecture, BERT, is employed [63]. This model, through its self-attention mechanism, can accurately capture contextual information within texts [64], achieving precise categorization of semantic relationships among terms in the field of red culture. This method not only optimizes the structuring process of the data but also forms a rich collection of structured resources, providing a solid visual foundation for the design of a universal signage system.

Methods: analysis of universal design influencing factors based on “structure-humanity”

Overview of the methodology

To ensure that the design solutions achieve optimal practicality and inclusivity, we adopted a “structure-humanity” model to analyze the factors influencing the design of the universal signage system. This approach thoroughly integrates physical structures and humanistic factors, enabling designers to create signage systems that meet technical standards and align with users’ cultural and social needs.

In the structure dimension, we utilized structural equation modeling to explore how perception, comprehensibility, and visual cognition affect the design of the universal signage system. Applying the structural equation model allowed us to accurately assess the impact of perception on comprehensibility and how these two factors together promote visual cognition, thereby enhancing the effectiveness of the signage system design. The analysis primarily focused on the physical characteristics of the signage system, such as its visual features and spatial layout.

In the humanity dimension, we focused on evaluating latent variables, such as users’ prior knowledge and experience, and how the signage system meets the cultural and social needs of different user groups. It included language diversity, cultural sensitivity, and the social relevance of the signage content. By collecting and analyzing user feedback, this dimension aims to optimize the universality and acceptance of the signage in multicultural and multilingual environments.

By integrating these two dimensions and using an interdisciplinary approach to evaluate and optimize signage design, we comprehensively understood the system’s functionality and cultural adaptability. It ensures that our design solutions are both practical and widely inclusive.

Data collection and participant characteristics

This study collected data through questionnaires and semi-structured interviews [65]. Before participants joined the study, they received basic information about the research and were required to review an information sheet and sign an informed consent form. Participant recruitment was primarily conducted online, including QQ, WeChat, Weibo, Douyin, and Xiaohongshu. The study began by distributing questionnaires through Wenjuanxing and email to groups of students, young adults, and older adults who had visited the Ruijin Soviet Heritage Site. Participants were encouraged to share the survey within their social networks to ensure a diverse sample covering various ages, genders, educational levels, and cultural backgrounds [66].

In building and evaluating the structural equation model, having an appropriate sample size is crucial to ensure the accuracy of estimates and statistical power. Typically, each latent variable in the model should be represented by 10 to 20 samples [67] to ensure the reliability of factor and path coefficients. The data collection lasted 12 days, receiving 485 attempted responses. Considering the complexity of the study model and the involvement of multiple latent variables and observational indicators, we excluded 33 invalid samples, retaining 452 valid samples. Among these, 26.6% were students, 39.8% were young adults, and 33.6% were older adults. Additionally, 42% of the respondents worked in design and cultural education, suggesting that the demographic profile of the survey sample aligned well with the typical characteristics of the target users. This alignment helps ensure the reliability and relevance of the statistical results.

Participants for the semi-structured interviews were selected based on the following criteria: their profession (such as designers, cultural education workers, and other related professionals), their knowledge related to the design of cultural heritage sites, and their experience and personal interest in cultural heritage.

For individuals with visual impairments, significant differences may exist in their cognition and interpretation of graphics and colors, which could affect their understanding of universal design elements such as graphic symbols and color coding. The specific needs of visually impaired individuals in terms of color contrast, brightness perception, and graphic recognition may increase data variability [68]. Therefore, in the initial stages of the research, controlling the visual capabilities of participants helps the research team assess the baseline effects of universal graphics without visual impairments.

To minimize the introduction of additional variables due to differences in participants’ visual abilities and to make the research results easier to analyze and interpret, all subjects are required to undergo a visual acuity assessment before testing. Only those with normal or corrected-to-normal vision are allowed to participate. All participants were clearly informed of the purpose of the study, and they were given the option to withdraw at any time.

To ensure the scientific validity and reasonableness of the interview sample size, statistical principles were used to determine the appropriate sample size. Based on specific research conditions, with a 90% confidence level and a 25% acceptable margin of error, the required sample size was calculated using the sample size estimation formula [69]:

$$\text{n}=\frac{{\text{Z}}_{\alpha /2}^{2}\times\uppi (1-\uppi )}{{\text{E}}^{2}}$$

The \({\text{Z}}_{\alpha /2}\) corresponding to a 90% confidence level, obtained through threshold querying, is 1.645. π is the expected proportion of the response distribution, usually assumed to be the most significant uncertainty. E denotes the margin of error, set at 25% in this study. Applying the above formula, the minimum sample size required is 22. Therefore, to maintain a 25% margin of error at a 90% confidence level, 22 typical samples were selected for interviews, considering variations in age, gender, and cultural background. Among these were 12 males and 10 females, aged between 18 and 60 years old. Additionally, there were 7 individuals engaged in design and 4 in cultural education. It is noteworthy that all participants had normal or corrected-to-normal vision.

Experiment preparation

In the experiment, the design of graphic sizes adhered to the principles and requirements of GB/T 16903-2021, with all symbol areas clearly defined by subscripts. Due to the unique nature of revolutionary figures and photographic images, these two types of cultural symbols were not included in the scope of this experiment’s evaluation. In order to control experimental variables, all symbols were maintained at their original angles without rotation.

Furthermore, the color scheme for the signage followed the guidelines of GB/T 38655-2020 (Human Ergonomics Design and Setup Guide for Public Information Guidance Systems). It also used the color contrast ratio formula from the WCAG (Web Content Accessibility Guidelines) to assess the contrast between two colors.

The contrast ratio formula according to the standard is as follows:

\(\text{Contrast }=\frac{{\text{L}}_{1}+0.05}{{\text{L}}_{2}+0.05}\) (L refers to the relative brightness of a color), contrast scale (1–3, 3–4.5–4.5), rating (FAIL, AA, AAA).

As people age, their visual recognition capabilities usually decline, necessitating higher color contrast and brightness to improve object recognizability for the elderly. Additionally, making the right color choices is crucial for colorblind individuals to enhance their ability to distinguish colors. According to existing research, elderly individuals have better color recognition within the red-to-yellow (YR-GY) spectrum, particularly when red is used as the background color, where the recognition effect is notably pronounced [70].

For this study, we chose a red color with RGB values of 230, 0, 18. Calculations show that this color has a contrast ratio of about 4.8 against a white background, which helps to improve the recognition rate of graphic symbols. Furthermore, considering the human perception of colors, we also converted the color values to the HSV (Hue 354, Saturation 100, Brightness 90) color model for further design optimization [71]. During visual testing, the color value was set as a fixed variable to ensure the accuracy and consistency of the test results.

Questionnaire design and experimental process

The experiment was conducted in two parts, initially using a 5-point Likert scale to measure all items. The design of this scale was based on McDougall’s evaluation standards for 239 icon features [72], with a scoring range from 1 (strongly disagree) to 5 (strongly agree). The primary method used was a questionnaire survey, which included two parts: the first part aimed to collect demographic information from participants, such as educational level, gender, age, and whether there were any visual impairments; the second part focused on assessing participants’ ability to recognize graphic symbols, their visual prominence, and their understanding of the symbols’ meanings, exploring the relationship between perception, comprehensibility, visual cognition, and the design of universal signage systems.

In order to ensure the validity of the questionnaire content, this study invited three experts in the field to review it. By integrating their professional feedback, we optimized the measurement items to ensure each item was closely aligned with the design objectives. After several revisions, the final version of the questionnaire was formed. Additionally, to ensure the equivalence of the questionnaire across different languages, we arranged for a bilingual researcher to translate the questionnaire from English to Chinese, and another researcher to back-translate it into English to verify the consistency of the translation.

The second part consists of face-to-face semi-structured interviews, from which we extract valuable information to build a preliminary data corpus. Before each interview, researchers thoroughly explain the purpose and principles of the interview to participants, ensuring confidentiality. Each interview lasts approximately 8 to 15 min. Researchers obtain informed consent from participants and keep audio and written records. To ensure the validity of the interview content, a pilot test was conducted first. Based on the feedback from two pre-test participants, adjustments were made to the questions and statements in the interview outline to finalize it.

Specific application scenarios are preset before asking participants about their understanding of the meanings of graphic symbols. The evaluation criteria are as follows [73]:

  1. (1)

    Responses that accurately describe the symbol elements are considered correct, such as “earth” or “sheaf of wheat.”

  2. (2)

    Responses that explain the implicit meaning of the symbol, even if the symbol element name is not directly mentioned, are also considered correct, such as describing the symbol as “building” rather than “house.”

  3. (3)

    Not using specific symbol names, as long as the description accurately reflects the core elements of the symbol or the concepts it represents, is considered correct. For example, describing the symbol as “a three-sided wireframe” rather than specifically as “a display stand” is acceptable.

  4. (4)

    The answer is correct if it can comprehensively identify and explain multiple symbol components. For example, describing “a farmer” instead of specifically “a person wearing a straw hat” would be acceptable.

Results

Reliability and validity test

The study employed confirmatory factor analysis to examine the reliability and validity of the questionnaire, as shown in Table 2. Reliability refers to the consistency and stability of test results, reflecting the accurate measurement of the characteristics being tested. Validity assesses how precisely an evaluation system measures and reflects the intended evaluation objectives and criteria [74]. Cronbach’s alpha and Composite Reliability (CR) are critical tools for assessing questionnaire reliability, while factor loadings and the Average Variance Extracted (AVE) are used to evaluate validity [75]. The results indicate that all Cronbach’s alpha values exceeded 0.7, and CR values exceeded 0.7, demonstrating good internal consistency within the questionnaire. Additionally, all standardized factor loadings were highly significant (P < 0.001) and exceeded 0.6, with AVE values above 0.5, indicating good convergent validity. Moreover, the square roots of AVE were higher than the corresponding values in the correlation matrix, indicating good discriminant validity between different questionnaire constructs. See Table 3. These data suggest that the questionnaire possesses good reliability and validity.

Table 2 Reliability and convergent validity
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Table 3 Results of discriminate validity (n = 452)
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Model fitting analysis

Path coefficients are commonly used in Structural Equation Modeling (SEM) and path analysis to measure the strength and direction of relationships between variables. The study utilized Amos 26.0 software for SEM analysis, as shown in Fig. 3. Fit indices such as Chi-Square (chi-square), degrees of freedom (df), Chi-Square to degrees of freedom ratio (chi-square/df), Standardized Root Mean Square Residual (SRMR), Root Mean Square Error of Approximation (RMSEA), Tucker-Lewis Index (TLI), and Comparative Fit Index (CFI) are used to evaluate the fit between the data sample and the research model [76]. The model fitting analysis reveals the relationships between constructs and their corresponding measures, as well as the suitability of the research model. By comparing these indices with standard values, the results indicate that the model constructed for studying the application of visual cognition in the design of universal signage systems shows a good fit, suggesting that the model is well constructed and that further path analysis can be conducted. See Table 4.

Fig. 3
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Path diagram. Theoretical model path coefficient of factors influencing the design of universal signage systems

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Table 4 Fit indices of the measurement and research models (n = 452)
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Hypothesis path test

The study employed Structural Equation Modeling (SEM) to test the hypothesized pathways in the theoretical model. This approach helped identify how perception and comprehensibility influence visual cognition and their impact on the design of universal signage systems. See Table 5. The results indicate that visual cognition has a positive impact on the design of universal signage systems (β = 0.348; P < 0.01), with perception (β = 0.369; P < 0.01) and comprehensibility (β = 0.366; P < 0.01) each positively affecting visual cognition. Regarding the visual cognition of graphics, only the shape of symbolic elements positively affects the perception of graphics (β = 0.334; P < 0.01). In the factors related to the comprehensibility of graphics, the familiarity of graphics (β = 0.245; P < 0.01), the semantic distance of graphics (β = 0.373; P < 0.01), and the rationality of graphic usage (β = 0.164; P < 0.01) positively influence the comprehensibility of graphics, and perception (β = 0.239; P < 0.01) also positively impacts comprehensibility. In summary, factors related to the comprehensibility of graphics have a greater influence than those related to perception. Elements such as the shape of symbols, familiarity with graphics, semantic distance, and the rationality of graphic usage positively affect visual cognition. These factors, in turn, impact the universality of the signage system.

Table 5 Results of path coefcients hypotheses (n = 452)
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Mediation effect test

To verify the proposition of a mediating effect in the design of universal signage systems in terms of visual cognition, the perception of graphics and the comprehensibility of graphics were used as mediating variables. Bootstrap sampling was employed with 5,000 resamples to obtain the 95% confidence intervals (95% Boot CI) between the constructs [77]. See Table 6. The results indicate that both the perception and comprehensibility of graphics show significant mediating effects in influencing the path of visual cognition.

Table 6 Mediating effect (n = 452)
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Subjective evaluation and analysis

In the process of information transmission via public information graphic symbols, participants’ visual cognition is influenced not only by the current information but also by the information they have previously accumulated [26]. Participants typically use their knowledge and experience to interpret symbol information. Most can accurately identify and describe common symbol elements such as “earth” and “flags.” However, they exhibit varying difficulty in understanding more abstract symbol elements. When these symbols are combined into a complete scenario, even if the scenario has been pre-set, understanding often becomes more challenging. Non-tangible graphic symbols usually represent abstract concepts or intangible cultural values, leading to differences in cognitive decoding among individuals. Familiarity, the complexity of the symbol, and its concreteness affect the smoothness of information processing [78], thereby impacting the effectiveness of visual cognition.

Factors affecting the design of universal signage system

Symbolic element modeling significantly positively influence perception

The significant positive impact of the modeling of symbol elements on perception can be deeply analyzed from the lens of semantics. Semantics, as a discipline studying cultural symbols and their representation of cultural, artistic, and social values, offers a crucial viewpoint for understanding the impact of symbol design. Semantic analysis often involves interpreting the explicit and implicit semantics of symbols, namely the signifier (the form of the symbol) and the signified (the meaning derived from the symbol). Explicit semantics are primarily manifested in the external appearance of symbols, such as their shape, color, patterns, and materials [79], where the intuitiveness of the modeling is critical to enhancing perception.

Research indicates that the visual clarity of symbols directly affects the cognitive load on observers. Studies by Zhang Qian and others emphasize that consistent and regular symbol forms can reduce visual distractions, thereby increasing perceptual processing speed [80]. In symbol design, colors not only enhance the attractiveness of symbols but also improve their recognizability. High contrast in color configurations effectively draws user attention and enhances memory retention [81]. These factors constitute the signifier aspect of the symbols of the Ruijin Soviet era, directly impacting observers’ perceptual responses and conveying specific cultural and social information through visual elements.

When designing symbolic elements, it is essential not only to consider their explicit, intuitive meanings but also to explore their implicit semantics. These deeper meanings may not be immediately visible, yet they evoke strong cultural or emotional connections, such as the spirit of red culture or abstract concepts like red art. This profound interpretation of semantics is critical in ensuring the cultural sensitivity and social acceptance of the design, especially in an environment of cross-cultural communication and globalization. Cultural background plays a decisive role in the perception of symbols, and people from different cultural backgrounds may interpret the same red symbol differently [82]. In cross-cultural communication, balancing the universality and specificity of symbol forms becomes especially critical. Effective symbol design must not only convey clear and understandable information but also inspire and guide deeper emotional and cultural resonances. Through carefully designed intuitive symbol elements and the interaction of forms between symbols, the universality and impact of the Ruijin Soviet red cultural information can be enhanced, enabling audiences from diverse cultural backgrounds to appreciate its profound cultural and emotional value.

Familiarity, semantic distance, and rationality of graphic usage have a significant positive effect on comprehensibility

There is a positive correlation between the familiarity of graphics and comprehensibility. Familiar visual stimuli can more efficiently activate the cognitive system’s related knowledge structures and memory content, thereby accelerating the processing and understanding of information. Specifically, when participants encounter familiar graphics, they can quickly invoke prior experiences and semantic information associated with that graphic. Particularly for the elderly, as sensory systems like vision, hearing, and touch decline with age, older adults increasingly rely on long-term memory to process new information [83]. For example, symbols of red heritage sites and red artifacts can be immediately recognized and understood because these graphics are concrete and encoded in participants’ long-term memory, closely associated with specific functions or information.

Similarly, the semantic distance of graphics also correlates positively with comprehensibility. The semantic nature of graphic symbols enables them to convey a large amount of information quickly and efficiently. They can bridge language barriers, reduce cognitive load [84], and streamline cognitive processing [85]. The relationship between icons and their meanings, emotions, and concepts reflects the connection between the icon and the historical and cultural significance of the Ruijin Soviet era. This connection is essential for understanding how graphic symbols convey the characteristics of specific historical periods. For instance, specific shades of red are often associated with revolution and socialism, and symbolic elements like hammers and sickles are used to strengthen the connection with the Soviet era, thus influencing and shaping public memory and cognition.

The rationality of graphic usage significantly positively impacts comprehensibility. Research shows that a centralized graphics layout is more efficient in visual search than a dispersed layout [86]. Therefore, when designing signage systems for red cultural heritage sites, a centralized layout strategy should be used to enhance the visual appeal of the signs, enabling participants to more quickly recognize and understand important information related to the heritage site. By optimizing the organization and presentation of graphics, the deeper meanings of red culture can be more effectively conveyed, thereby enhancing visitors’ experiences and educational values. At the same time, compared to using text or graphics alone, a design that combines graphics and text is more effective on a cognitive level [87]. Thus, in the design of signage systems, employing a “graphic symbol + specific language text” format can not only effectively convey directional information [88] but also enhance the global visual and spatial recognition of the signage system.

Perception and comprehensibility have a significant positive impact on visual cognition

Perception and comprehensibility of graphics are positively correlated with visual cognition. Visual cognition refers to the psychological process of acquiring, processing, organizing, and interpreting information in the environment through the visual system. In the study of the universal signage system at the Ruijin Soviet Cultural Heritage Site, participants’ cognitive processes are primarily divided into three stages: graphic capture, form recognition, and target matching with behavioral response [89].

During the graphic capture and form recognition stages, participants perceive and understand the visual features of the signs, such as shape, color, and size, focusing their selective visual attention on specific signs. In the target matching and behavioral response stage, participants not only identify the graphics, symbols, and text within the signage but also integrate their prior knowledge and experience to infer the meaning of the signs [90]. By analyzing the shape, color, and arrangement of the signs, participants can accurately interpret the information conveyed by the signs. Using universal signage symbols makes it easier for participants from different regions to understand the signs. This approach promotes the standardization of red signage while incorporating the cultural elements and design of the Ruijin Soviet era. As a result, it enhances the recognizability of the signs and enriches participants’ cultural experience [91].

Visual cognition has a significant positive impact on universal signage system design

Visual cognition is positively correlated with the design of universal signage systems. When designing universal signage systems, it is essential to consider how to optimize information recognition and understanding through visual elements. This research encompasses multiple influencing factors, including the impact of the spacing and size of icons on recognition [92], the influence of the contrast and clarity of graphic symbols on visual interpretation, the effects of participants’ cultural backgrounds and languages on interpreting graphic symbols [93], and the impact of visual sensitivity on the recognition of graphic symbols.

Therefore, when designing universal signage systems for red heritage sites, it is necessary to comprehensively consider these factors, adjusting the spacing, size, and contrast of graphics and text in the signage to enhance readability in various visual environments. Selecting simplified and concrete graphic symbols allows participants from diverse cultural backgrounds to better understand and appreciate the history and value of heritage sites. This approach ensures that the signage is not only visually recognizable but also meets the needs of users from different cultural and linguistic backgrounds.

Additionally, considering the special needs of the elderly and visually impaired, the design should pay special attention to these groups’ visual sensitivity, using larger fonts and more distinct color contrasts to ensure the universality and inclusiveness of the signage system. Through this comprehensive and integrated design approach, the signage system at red heritage sites can not only effectively convey historical information but also greatly enhance the experience of all visitors, making it a vital visual medium for connecting with the red cultural experience.

Discussion: design strategies for universal signage system

The design of a universal signage system for the Ruijin Soviet Heritage Site should focus on the expression of graphics, the environment of use, and narrative strategies. By reducing the number of non-physical symbols, optimizing the shape of symbolic elements, and employing a combined display of text and graphics [94], the design should be guided by heritage tourism routes and the environment. It should revolve around the visual guidance system, the visual planning of heritage tourism paths, the integrated use of multimedia and interactive technologies, and the innovative design of heritage site souvenirs. This approach aims to enhance the public’s experience of cultural heritage sites and their understanding of red culture, further promoting the dissemination of red cultural heritage and the realization of sustainable tourism.

Perception-oriented universal signage system design strategy: tourism information services for cultural heritage sites

Division of spatial categories and signage categories

Different spaces carry various types of information due to their unique functional requirements, and these differences in the nature of information significantly impact the content structure and constituent elements of information interfaces [95]. The Ruijin Soviet Heritage Site includes a variety of spaces, such as the Central Revolutionary Base History Museum (indoor space), the Temporary Central Government Auditorium of the Chinese Soviet Republic (outdoor space), and historical sites like Yeping and Hongjing revolutionary sites. Depending on the function of these spaces, various types of signage systems are involved, including information-type signage, orientation-type signage, explanatory-type signage, and prompting-type signage.

Indoor space’s information-type signage primarily showcases revolutionary historical content and cultural relics, while orientation-type signage ensures visitors follow designated paths, ensuring a smooth and comprehensive visiting experience [96]. Explanatory-type signage delves into the background stories and historical value of cultural exhibits. In contrast, prompting-type signage focuses on safety guidance, such as indicating safety exits and emergency evacuation routes. Outdoor space’s information-type signage conveys both historical information and introduces natural landscapes. Orientation-type signage guides tourists to explore revolutionary sites, explanatory-type signage provides background information on significant historical locations, and prompting-type signage emphasizes guiding visitor behavior and highlighting the importance of natural conservation. See Fig. 4.

Fig. 4
figure 4

Identification layout analysis. Classification and layout of signage for various scenic spots in Ruijin Soviet cultural heritage site

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Standardized design of visual guidance system

When handling a large volume of information in public wayfinding systems, optimizing through hierarchical signage and system numbering can ensure clear transmission and effective management of information, aligning with the logic and needs of users for obtaining information.

Through a comprehensive numbering scheme, the navigability and maintainability of public wayfinding systems can be significantly enhanced. In the signage system, hierarchical prefixes are introduced to indicate the level of guidance: Level one signage, marked as “C,” primarily emphasizes the overall layout of the location, major facilities, and critical area positions, usually placed in prominent locations such as entrances or central transit nodes to help visitors quickly understand the spatial layout; Level two signage, marked as “D,” focuses on specific directional and traffic-diverting information, typically positioned at critical intersections and decision points in the space, such as directions to specific exhibition areas or other service facilities; Level three signage, marked as “E,” provides detailed supplements to the comprehensive information in level one signage, including details of exhibits, historical background, or specific functionalities of particular areas; Auxiliary signage, marked as “S,” focuses on management information, such as facility maintenance, safety guidelines, and service notifications. See Table 7.

Table 7 Standardized design of visual guidance system
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Comprehensibility-oriented universal signage system design strategy: visual design for heritage corridors

Visual design of public guidance system for heritage sites

According to a study by the Architectural Institute of Japan, the average mid-point height between the eye levels of adults and wheelchair users is approximately 1.35 m. The study pointed out that the center of vision for adults and wheelchair users is slightly lower than the mid-point height. Therefore, to accommodate the needs of particular groups, the center height of the visual guidance signs has been adjusted to 1.25 m [97].

Indoor wayfinding systems need to be integrated with the architectural structure and aligned with the functional areas of the venue [98]. These systems primarily consist of index signs and exhibit description signs. Index signs are typically placed at the entrance of the museum, including functional direction boards and hanging signs, providing visitors with initial guidance and spatial layout information. These signs mainly feature floor plans, exhibit icons, textual information, and directional indicators. The design of the hanging signs must consider the visibility and legibility of the information in poorly lit environments [99]. This can be achieved by using illuminated materials or backlighting technology to ensure that the information is clear and readable under different lighting conditions. Exhibit description signs provide detailed annotations about the displayed artifacts, typically including location maps, exhibit icons, and textual information. Acrylic materials are chosen for their durability, environmental friendliness, resistance to fading, and anti-glare properties. Acrylic is also easy to process and shape, ensuring the information’s long-term effectiveness and visual quality [100].

The design of the outdoor wayfinding system focuses on core visual elements [101], presenting the overall image of the Soviet-era republic to the public. It includes comprehensive information boards, directional signs, traffic-diversion signs, identification signs, and explanation signs. Comprehensive information boards are located at the entrance of the heritage site cluster, using a left–right layout: the left side provides an overview of the scenic area. In contrast, the right side outlines the general information of the heritage sites. Directional signs are placed along the visiting route to guide visitors along the planned path; traffic-diversion signs are located at branching points to assist visitors in making navigation decisions [102]; identification signs are attached directly to the walls of each heritage site to facilitate recognition and memory; explanation signs are placed at the entrance of each site, offering detailed information about the site.

Visual cognition-oriented universal signage system design strategy

Theme station design

Cultural symbols are vital elements in shaping the historical and cultural characteristics of a city and have a profound impact on the construction of its image [103]. The design, use, and management of urban spaces reflect the social structure and cultural values. By integrating red graphic symbols and their related information into public spaces, such as the signage design in subway station waiting areas, these symbols not only beautify the public environment but also strengthen the public’s identification with the red culture and its underlying socialist ideology through frequent contact during daily commutes [104].

Taking the rich revolutionary history and culture of Ruijin into account, the city incorporates this into public spaces, focusing on red culture as the core of its design. For example, in the transport system of the Ruijin Soviet Republic, the design theme revolves around “Red Stories, Red Memories, Red History, Red Spirit.” Specifically, a historically significant station could be selected, such as the “Red Heritage Route” station, using “Red Anthem” as its design theme. A circular art wall could be set up at the station as the centerpiece to display the glorious journey since the establishment of the Ruijin Soviet Republic, inviting passengers to witness the profound changes in the fate of the Chinese nation. Ruijin’s thematic station design effectively integrates the profound legacy of red culture with modern transportation spaces through innovative interventions such as issuing themed tickets and setting up themed check-in points.

Cultural corridor design

Road domain culture reflects the various cultural phenomena within a specific road section, including natural scenery, cultural landscapes, cultural signage systems, and behavioral habits [105]. In Ruijin, our team has ingeniously integrated the revolutionary site cluster with the road space by creating a red culture corridor, forming a new model that combines the sense of place, tourism experience, and educational significance [106]. Especially in the thematic districts of the Ruijin Soviet period, symbols of the era such as “Persist in Revolution,” “Oppose Imperialism,” “Support the Worker-Peasant Alliance Policy,” and “Persist in Land Revolution” are everywhere. These slogans, written in red or black, along with the surrounding historical buildings, create an atmosphere filled with revolutionary zeal and the spirit of public struggle. In this way, red culture is not only organically integrated into the spatial layout but also creates a rich thematic atmosphere of red culture on visual and perceptual levels.

Multimedia and interactive technology applications

The smart guide system is located at the entrance of the exhibition hall, providing visitors with preliminary information about the artifacts inside the exhibition. The design strategy of this system is to present information in layers, aimed at gradually enhancing visitors’ cognitive and exploratory experiences [107]. The first level of the system mainly introduces the overall classification of data related to red culture, helping visitors quickly understand the range and categories of content displayed in the exhibition hall. In the second level interface, the system details the classification, level, and preservation status (intact or damaged) of each artifact based on the type of red culture data, using a timeline format. The third level interface provides a detailed introduction to individual artifacts, including their morphological features, provenance, and artifact level.

Heritage site souvenir development

Red cultural and creative products, as storage mediums for red culture memory and bearers of symbolic value, effectively integrate the spirit of red culture with modern life [108]. Red Creative products still have room for improvement in cultural depth and market application. They have not fully met the diverse needs of the market and consumers. As an essential part of contemporary tourism innovation and cultural construction, red tourism is crucial in innovating red tourism souvenirs. These souvenirs are tourism commodities and core carriers of red cultural heritage [109], emphasizing their unique cultural attributes and functions.

Taking the Ruijin Soviet Cultural Heritage Site as an example, the region can adopt a “1 + 1 + N” management model for cultural and creative development: the first “1” represents the Ruijin Soviet Cultural Heritage Site itself, the second “1” represents a dedicated cultural and creative operations company, and “N” represents collaboration with multiple third-party partners responsible for product development, production, media dissemination, and channel promotion. Under the guidance of the heritage site, the cultural and creative operations company utilizes rich red historical resources, in conjunction with permanent and temporary exhibitions, to develop and promote red cultural and creative products. Through standardized and process-oriented authorization management, this model promotes the active participation of multiple resources.

We will design various products themed around significant historical events of the Ruijin Soviet era, forming an intellectual property protection and full-channel operation management system centered on red elements and products. These products blend red cultural symbols with everyday items, such as tote bags, T-shirts, and commemorative coins featuring relevant designs. It not only showcases the essence of Ruijin Soviet culture but also strengthens the public’s connection to red culture, helping to spread its values more widely and deeply.

Conclusions, limitations, and future research

This study investigates the sustainable development of cultural heritage by digitizing the Ruijin Soviet’s red resources and creating a visual resource library. It also conducts empirical research on the key factors influencing the signage system, drawing on theories from semiotics, Gestalt psychology, cognitive psychology, and semantics. The research follows a “structure-humanity” approach to analyze these universal factors. The study finds that visual cognition has a significant positive impact on the design of universal signage systems. The perception and comprehensibility of graphics positively influence visual cognition, and the perception of graphics will positively affect their comprehensibility. Symbolic element modeling, familiarity of graphics, semantic distance of graphics, and the rationality of graphic usage will positively affect the visual cognition of graphics, thus influencing the universality of the signage system. Based on these findings, a universal signage system design pathway suitable for cultural heritage tourism routes has been developed. This pathway comprehensively considers the interrelationships between graphic perception, comprehensibility, and visual cognition, focusing on optimizing graphic expression, environmental adaptability, and narrative methods. It aims to effectively popularize heritage culture to all groups through heritage tourism routes.

Although this study contributes both theoretically and practically, it also has some limitations. The sample, while extensive, does not cover all user groups, particularly ethnic minorities and non-Chinese/English speakers. The limited sample size may affect the general applicability and acceptance of the research results. For future research, it is suggested to:

  1. 1.

    Integrate diverse measurement indicators: Conduct more cross-cultural adaptability studies, particularly on how signage systems can better serve domestic and foreign visitors with different cultural backgrounds. It includes exploring differences in understanding symbols, colors, and text information across different cultural backgrounds. By introducing a broader range of measurement indicators, such as user satisfaction, cognitive load, and memory retention, the actual effects of the signage system can be comprehensively evaluated, and the understanding and acceptance of non-local visitors can be improved.

  2. 2.

    Use objective and diversified research techniques: Design experiments to simulate different usage scenarios and apply technologies like EEG and eye-tracking to record users’ behavioral and physiological responses. These technologies can precisely measure users’ cognitive activities and visual attention distribution when interacting with signage, providing researchers with deep insights into optimizing signage design. Through these data, the effectiveness of different design elements can be evaluated, analyzing how they influence users’ decision-making processes and how they can evoke users’ emotional and cognitive responses.