Table 1 Position of the characteristic absorption bands in the reflectance spectrum and first derivative inflection points for each synthesized pigment

C-Std M-R

Alumina, SO₄²⁻

~ 495

530 ± 3

557 ± 1

500 ± 0

540 ± 1

C-Std M-Ca excess

CaCO₃, alumina

~ 496

529 ± 2

560 ± 2

500 ± 0

540 ± 3

C-Std M-Ca

CaCO₃

~ 497

530 ± 2

561 ± 1

501 ± 1

540 ± 2

C-Std M

Alumina, SO₄²⁻

~ 495

531 ± 2

559 ± 2

500 ± 0

540 ± 2

C-Std M-Al ex.

Alumina, SO₄²⁻, CO₃²⁻

~ 494

530 ± 2

558 ± 2

499 ± 1

539 ± 1

C-Silk

Alumina, SO₄²⁻, CO₃²⁻

~ 496

528 ± 2

559 ± 1

500 ± 1

539 ± 2

C-Fleece

Proteins, alumina, SO₄²⁻

~ 497

529 ± 3

558 ± 2

502 ± 3

537 ± 1

C-Sn

Sn salt or complex

~ 485

520 ± 0

555 ± 1

501 ± 2

535 ± 1

C-Al

Al salt or complex

~ 493

538 ± 3

574 ± 3

503 ± 3

545 ± 2

DYE15046^a

Al salt or complex

~ 489

523 ± 1

562 ± 2

496 ± 1

533 ± 1

DYE15047^a

Al salt or complex

~ 489

526 ± 0

562 ± 1

500 ± 1

537 ± 2

M-Std

Alumina, SO₄²⁻

~ 481

509 ± 3

~ 548 (sh)

490 ± 2

524 ± 1

M-Std-R

Alumina, SO₄²⁻, CO₃²⁻

~ 469

500 ± 5

~ 545 (sh)

~ 488 (sh)

522 ± 1

M-Std-Al ex.

Alumina, CO₃²⁻

~ 475

500 ± 2

~ 538 (sh)

~ 486 (sh)

520 ± 2

M-Std-Ca

CaCO₃, alumina

~ 476

506 ± 0

− ~ 545 (sh)

487 ± 0

524 ± 0

M-Std-Ca excess

CaCO₃, alumina

nd

480 ± 5 (broad)

~ 543 (sh)

~ 487 (sh)

~ 523 (sh)

M-Silk

Alumina, SO₄²⁻, CO₃²⁻

~ 478 (or maximum, if present)

~502 (sh)

~ 541 (sh, if present)

~ 486 (sh)

524 ± 2

M-Fleece

Proteins, alumina, SO ²₄

~ 478

505 ± 3

~ 542 (sh)

488 ± 1

523 ± 1