I have finally gotten around to reading Josef Albers classic “Interaction of Color”. This is quite extraordinary text on the perception of color with perhaps the most fascinating thoughts relating the sensation to music. This may have inspired Edwin Land to this analogy (quoted elsewhere on the webpage). Quoting Albers:
I believe that with the substitution of a few words this could describe the process of light interaction with the retina and its subsequent synthesis into the visual scene!
I have been loathe to use psycho-physiological color illusions to suppport my geometrical hypothesis but a passage by Albers got me to thinking:
It ocurred to me that this is the inverse of the familiar “Union Jack” after-image color illusion. This illusion is well described in the BBC film “Colourful Notions” (discussed elsewhere on the page) and can be viewed on a number of webpages found by a Google search. In this illusion an image of the Union Jack is presented in blue and green ( greenish yellow on my TV screen). After staring at the image for 20 seconds or so a white screen is presented where a startling true red and blue after-image is seen.
The geometrical hypothesis would predict that the red bands in the after-image should be more well defined than the blue areas since long wavelengths are directed to the all-cone fovea resulting in detection of the basic optical or Fourier transform that I have termed the “Marr sketch”. Short (blue) radiation is directed to more peripheral retinal areas with the result being a more diffuse image. Thus there should be a difference in the spatial perception of the two colors in the after-iamge.
And… after viewing the illusion a number of times (from the “Colourful Notions” film) I believe that this is exactly the case with the red bands being sharper outlined than the hazy blue areas.
And…since the illusion involves a sudden transformation from a colored to a bright white screen this should result in a suddenconstriction of the pupil of the viewer’s eye. This hypothesis proposes that short wavelength (blue) radiation is involved in the mechanical action of constricting the pupil. One might therefore guess that pupillary constriction might enegnder some lag (or “hunting”) in the blue color signal. Again, in viewing the illusion this does seem to be the case..the blue color seems to “flicker” for an instant while the red color is relatively constant.
Please view the illusion for yourself!
