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RE: Colour Vision

Adrian Thomas wrote:-
>>Ishihara takes the form of a book with with coloured numbers printed on
speckled coloured backgrounds<< 

Not sure what printers inks are used to make the Ishihara tests, but
most of these colour blindness tests work on the basis of metameric
matching. In other words a particular red and a particular green
together appear as yellow, which can also be produced with a single
yellow patch, or with a different red and a different green. Under
different lighting, shot on different film or with different (abnormal)
vision, matched colours can appear different, or vice versa.

Since monitors are all about producing a colour gamut with just three
specific coloured phosphors, (which is, in itself, a form of metameric
matching)  I'd have thought that only a test based on colours produced
with those specific phosphors would be totally reliable.

That is, until someone develops a Farnsworth-Munsell 100-hue monitor

Notwithstanding the above, has anyone tried scanning the Ishihara tests,
displaying them on a monitor, and seeing how known colour blind subjects
and others score?

No questions about the colour response of the scanner please!

  Dominic Case
  Atlab Australia

Thanks to Blake Jones for support of the TIG in 1998.
No product marketing allowed on the main TIG.  Contact rob at alegria.com
925 subscribers in 36 countries on Wed Feb 18 19:18:41 PST 1998 
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