Figure 3

Correction of chromatic shift and evaluation with nanorulers. (a) Sketch of a GATTA-PAINT 80RG nanoruler used for this experiment. (b) Uncorrected merge of red and green SR-images showing a clear shift of ~90 nm. (c) Corrected overlay of the images. (d) Correlation image obtained by multiplying the red-and green values of the corrected image. Merged structures give a value > 0. (e,f) Full-size correlation images of multicolor beads (e) and nanorulers (f) showing the correlation density (summed up correlation amplitudes within 1.6 × 1.6 µm²-squares, normalized to maximum) in order to evaluate the correction quantitatively. Multicolor beads are limited to low surface densities while nanorulers show the desired homogenous correlation over the field of view within statistical noise.