First please enjoy this wonderful answer to How did Newton explain his interference rings without wave optics? which describes the story behind what we now call Newton's rings.
Below I show an example of the rings using a low pressure therefore fairly monochromatic sodium lamp; if angular spread is managed the number of fringes potentially viewable can be dozens or more. Then I show some examples of fringes using white light. These give some impression of what one would see, but the actual contrast we would see (or in photograph) in color depends on the spectrum of light and the spectral responses of the "color channels" of our vision system or the color camera used.
What Newton could do with a narrow beam of sunlight in a darkened room continues to floor me! He made ample use of prisms to separate sunlight into colors and he might have viewed "thin plate" or thin film or thin gap interference patterns with wavelength-restricted beams via prism dispersion.
But I wonder if he also looked at such interference effects by using color filters.
Question: Did Newton ever use filtered or prism-dispersed colored light to view "Newton's rings" or other thin-film interference effects?
(click for larger)
Newton's Rings as observed through a microscope. The lens used is a 20cm convex lens and the light source is a sodium lamp. Source
left: Source: Fundamental problems of 17th Century Physics The Nature (click for larger) right: Source: Newtons Ring, Engineering Physics by Dr. Amita Maurya, Peoples University, Bhopal
