3 public-domain matches

Contrast Sensitivity Vision

Cover of The colour-sense

The colour-sense

Grant Allen

Cover of Visual acuity with lights of different colors and intensities

Visual acuity with lights of different colors and intensities

David Edgar Rice

Cover of Über Kontrast und Irradiation

Über Kontrast und Irradiation

Armin von Tschermak-Seysenegg