Comments on: RGB Anomaloscope Color Blindness Test

By: Vinod

Vinod — Fri, 29 Jan 2010 19:23:55 +0000

Are you from United states….
Its a major process for health insurance in US… the medical coding is related to Health insurance cycle useful for quoting numerical codes for surgical procedures.

By: Daniel Flück

Daniel Flück — Fri, 29 Jan 2010 19:19:17 +0000

Vinod, the test can be done as many times as you like to.

What do you mean by “Medical coding perspective”?

By: Vinod

Vinod — Fri, 29 Jan 2010 17:06:05 +0000

How many times this test can be done in a day and can be coded for Medical coding perspective??

By: Dr. T

Dr. T — Wed, 20 Aug 2008 09:48:29 +0000

Well, it seems I was hasty. I redid the test, doing screenshots of every match and a number of no-matches and played around with it (@Daniel: I can send this to you, if you are interested). My first idea with the blue does not work out at all. But in addition to two matches, were both colors were really near identical, I had to more in which I compensated a small difference in green by a huge difference in red. In numbers: RG 234,234 matched by 31,255 and 208,208 matched by 255,205. I also was able from a close non-match 144,144 with 255,116 to fabricate a match 220,130. But if the green difference is >20, there is no match any more. I know from other tests that I am highly red-weak (protan), but green about normal. This fits nicely with the numbers I get on your test. Maybe the traditional plot is not appropriate for this emulation?

By: Daniel Flück

Daniel Flück — Tue, 19 Aug 2008 18:47:29 +0000

Dr. T, first I implemented two dials. But it seemed to complicated to me that everybody could do the test easily. So I removed one and inserted the “no match” button.

The problem really lies in the absence of a yellow color source in RGB. Because of that you can’t really construct metameric lights (yellow based either on yellow or on a mixture of green and red). If you could, a red-blind would see the red-green mixture darker than the “only yellow”. In RGB both is the same.

Looking at the colors in RGB both sides will always consist only of R and G. If you look at the CIE color space the mixture is like walking a straight line from R to G and the yellow side is like staying on the spot. On both sides yellow would change the hue and/or saturation which isn’t desired.