Stillings pseudo-isochromatische Tafeln zur Prüfung des Farbensinnes
Stilling's pseudo-isochromatic plates for testing colour vision, published in Leipzig by Georg Thieme in 1922 by the ophthalmologist Jakob Stilling for clinicians examining patients for colour deficiency. The pictures are pairs of square fields of dots in varied sizes and shades, where a figure such as a numeral or shape appears only in certain hues against a background of confusing colours, giving a designer a clear model for dot-pattern and camouflage-like textures built from hidden forms.
