tag:blogger.com,1999:blog-1840985738235902482.post3322503652299467209..comments2024-03-27T07:14:48.488-04:00Comments on John the Math Guy: Follow up on colorblindness testingJohn Seymourhttp://www.blogger.com/profile/11350487038873935295noreply@blogger.comBlogger14125tag:blogger.com,1999:blog-1840985738235902482.post-49295222707698607762018-01-17T15:22:09.072-05:002018-01-17T15:22:09.072-05:00A couple of random comments:
1) It seems a bit su...A couple of random comments:<br /><br />1) It seems a bit suspicious to compare an on-line hue discrimination test based on mixtures of RGB primaries to one based on pigments that might actually have a spectral peak in, say, the yellow or cyan region of the spectrum. This bears some relation to the idea of using more than three primaries for color reproduction, so that people with variations in color vision see something closer to what they see with the original scene spectrum.<br /><br />Has anyone thought of devising a three primary, two match point (yellow and cyan) anomaloscope, to test the discrimination of women who have four cone cell variants? This could settle the question of whether their color space is truly four-dimensional.Wayne Bretlhttps://www.blogger.com/profile/04219952662603590089noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-85583213587902850042015-09-08T01:19:09.828-04:002015-09-08T01:19:09.828-04:00A very useful blog. I am very much benefited after...A very useful blog. I am very much benefited after reading this post. Keep sharing.<br /><br />www.artificialeyeco.com/Anonymoushttps://www.blogger.com/profile/05612976014244749510noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-56700971529672889332012-12-22T20:38:05.475-05:002012-12-22T20:38:05.475-05:00I've taken the x-rite test a few times and gen...I've taken the x-rite test a few times and generally find it pretty easy to score perfectly. But then I color correct images almost every day. The monitor I use has settings for emulating various color blindness types and Martin's comment made me wonder how the test would play with the monitor set on deuteranopia emulation.<br /><br />The answer is: it's hard. I can image that a one or two of the lines might be doable if you were used to seeing the world this way. But the chips in the third line are all very similar in color making it, for me, impossible to even begin.<br /><br /> Markhttps://www.blogger.com/profile/10778575292054715137noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-67873589797552234842012-12-20T10:42:54.363-05:002012-12-20T10:42:54.363-05:00Martin, thanks for the further information. That&#...Martin, thanks for the further information. That's strange that someone who has colorblindness could score perfect, despite the fact that most people with normal color vision do not. It seems as though CVD is "in the eye of the beholder", while color acuity is in the brain.<br /><br />Jeff, excellent post, thanks for the followup. My explanation for the test working on a device with limited gamut is that, even though colors are distorted compared to what they are "supposed to be", the relative placement of colors is not changed much.John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-38200078440650224202012-12-19T18:55:58.203-05:002012-12-19T18:55:58.203-05:00Finally got around to posting my response to your ...Finally got around to posting my response to your response to my post...<br />Thought it might be interesting to really check the accuracy of some of these devices so I plotted Gretag Macbeth color checker colors as reproduced by an iPad mini and Nexus 7. The two devices reproduce this set of colors quite differently. Its interesting that this did not seem to affect your initial test results: http://wp.me/p1IEEo-5CAnonymoushttps://www.blogger.com/profile/00743995315908551370noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-37513954423665723132012-12-19T12:00:38.415-05:002012-12-19T12:00:38.415-05:00Let me echo the earlier comment: the "one tru...Let me echo the earlier comment: the "one true colourblindness test" (yes I'm European) is the anomaloscope: mix red and green lights to match a yellow stimulus. <br />I have been teaching color science for decades, and my view of the FM 100 test is coloured (!) by the deuteranope who scored perfectly on that test: it is a far better acuity test than it is a CVD (colour vision deficiency) test.Martinhttps://www.blogger.com/profile/17928986435630842562noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-35782668403423678232012-12-18T11:33:11.924-05:002012-12-18T11:33:11.924-05:00As a half Norwegian, I can attest that my indicato...As a half Norwegian, I can attest that my indicator light does the same thing!<br /><br />Thanks for the good joke.John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-26884575654182168032012-12-18T11:03:23.234-05:002012-12-18T11:03:23.234-05:00I liked the Norwegian jokes (we Swedes love jokes ...I liked the Norwegian jokes (we Swedes love jokes on especially Danes and Norwegians).<br /><br />An example: A Norwegian did his preflight check on the car before starting off, like every responsible driver does. But he got stuck when he came to the first indicator lamp: Works, doesn't work. Works, doesn't work. Works, doesn't work. Works, doesn't work. Works, doesn't work. Works, doesn't work. . .Anonymoushttps://www.blogger.com/profile/04096598783871940756noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-66636503962882546232012-12-15T09:23:11.241-05:002012-12-15T09:23:11.241-05:00Thank you, Unknown, for the information. You know ...Thank you, Unknown, for the information. You know that I just put a Nagel Anomoloscope on my Christmas list!!John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-54494580620997087852012-12-15T08:55:16.030-05:002012-12-15T08:55:16.030-05:00John,
I have been meaning to jump in this for some...John,<br />I have been meaning to jump in this for some time but have been pressed for time lately. The Ishihara plates are not the definitive test for colr vision deficiency - the Nagel Anomoloscope is. The Ishihara test is an example of a pseuoisochromatic plates. There are or at least were some competitive plates. The oldest that i have seen were sold by American Optical (same folks who make those really cool instruments in your optometrist's office. Those plates were designed by Hardy, Rand and Rittler so were known as the AOHRR plates (test). The were different in that they used geometric shapes ( circle, square, triangle) instead of numbers. They also had some supplementary plates with wiggley lines so the subject could simply trace the "spaghetti" across the plate. By the way, Hardy mentioned here was a professor at MIT who designed and built the first color measuring spectrophotometer ad wrote the first textbook on colorimetry, describing the newly published method of colorimetry recommended by the CIE.Unknownhttps://www.blogger.com/profile/03791815228024493846noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-60516519290417792402012-12-14T10:20:11.876-05:002012-12-14T10:20:11.876-05:00Hutch,
Sorry, the link to XRite's online test...Hutch,<br /><br />Sorry, the link to XRite's online test was buried as a link: http://www.xrite.com/custom_page.aspx?PageID=77<br /><br />It does seem odd that they are "giving the test away" online, when they make a bit of change selling the FM kits. (I am sure the kits are expensive to make, so I don't think the price is ridiculous.)John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-8122368319600756092012-12-14T10:17:17.791-05:002012-12-14T10:17:17.791-05:00Congrats on the perfect score, Steve! (mutter, mu...Congrats on the perfect score, Steve! (mutter, mutter, mutter under my breath... he must have a much better display than I have... I am sure he used a color picker tool to yank RGB values out of the image... As for the screen shots, I'm sure he is capable of downloading the HTML and putting in any score he wants...)<br /><br />You should be proud to have done so much better than I did!!!<br />John Seymourhttps://www.blogger.com/profile/11350487038873935295noreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-41289947162081341412012-12-14T09:33:42.677-05:002012-12-14T09:33:42.677-05:00So I go online to the X-Rite site, and search on o...So I go online to the X-Rite site, and search on online color challenge, no hits. Have they removed it to sell more FM Kits?<br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1840985738235902482.post-22054942609766151222012-12-12T11:02:01.569-05:002012-12-12T11:02:01.569-05:00Wow, that was a surprise! I took the online FM col...Wow, that was a surprise! I took the online FM color test and got a perfect score (I saved screen shots as proof). I've never thought my color perception was very good. I'm terrible when it comes to matching colors from memory. By the way, thanks for acknowledging the whole "Ollie/Ole" fiasco. I'm sensitive to it because my maternal, Norwegian-born grandfather's name was Ole.Steve Tesmerhttps://www.blogger.com/profile/04595487880736056406noreply@blogger.com