Slashdot Mirror

How does Vash work for color blind or other visually impaired individuals?

Despite its visually striking and distinctive impact, color plays only a small role in differentiating between Vash images.

Rather, it shows that the intent is right but the execution has failed: that no two images are differentiated only by being coloured differently is good, but that the shapes composing a given image are defined entirely as borders between colourfields is extremely problematic: because two adjacent colours may or may not even actually be distinguishable for the viewers--as someone who's protanomalous myself, I have difficulty even seeing any of those shapes that are defined purely by boundaries between fields of red/green or blue/purple; and some of the gradients actually make things even worse.... It's like the joke about the `drawing of a polar bear in a blizzard'. So, you've ended up making colour a much more important aspect than you think :) A couple of my favourite references on colour vision, and how to work with it:

• Color Universal Design (CUD) - How to make figures and presentations that are friendly to Colorblind people -
• Color Vision, Color Deficiency (an intro/guide for UI-, web- and other graphic designers)

There's one particular issue that's mentioned in the Firelily article, though only briefly, and it deserves being brought to attention--as a Slashdot commenter did some years back:

blue & red should not be placed next to each other, generally. Since they fall roughly at opposite ends of the visible spectrum, the eye's focal power differs the most between those colors. As your eye/brain tries to focus properly on two colors that require slightly different adaptations, you can perceive a "vibration" -- the boundary between the red & blue will have a high-frequency shimmering or vibrating appearance.

It may also be useful to read `Rainbow Color Map (Still) Considered Harmful'; there are some applicable lessons in there, though they're harder to find.

"Information technology" is a lot like stationary engineering as a career. Once upon a time, around 1900, stationary engineering was the hot field to get into. People were needed to run the high technology that made the wheels of the world go around - steam engines, generating plants, heavy industrial machinery. It was a new field - vast amounts of machinery were being built and installed, the technology was advancing rapidly, and the world was changing drastically as, for the first time in history, power was being made and distributed in quantity.

A century later, there are about 120,000 stationary engineers in the US. It's a union job, and a good one. Regular hours, OK working conditions, some shift work. It's a routine job, but one that needs to be done. That's where "information technology" is going.

Information technology was once a showpiece operation. Company computers were in glass-walled rooms and people would look in on the shiny machinery. Now they're racks in dark basements and warehouses. The same thing happened to stationary engineering. Steam engines and generating stations were once showpieces. Today, facilities like that are in bleak locations. Visited a boiler room lately?

I'm red-green colorblind, and I can tell the difference between those images. The colors in the second one look lighter and faded compared to the first one. Here is a page that has the Ishihara test patterns. Here is another page that has more detailed information. As a point of comparison, the two pictures of flowers about half way down the page (subtitled "red-insensitive dichromat") look very nearly identical to me.

BTW, it appears to be a doctored photo of a lily. I'm not sure what the original poster was trying to suggest.

BTW, it appears to be a doctored photo of a lily. I'm not sure what the original poster was trying to suggest.

Not really. The thing is, everyone's eyes are different.

As you probably know, our rods respond to the intensity of red, green, and blue light. More specifically, each type of sensor has its peak sensitivity at approximately those colors. Our red sensor responds a little bit to blue light, our blue sensor responds a little to red light, etc. Our eyes "know" there's a given wavelength of light based on the output from all three sensors. Thus, we can duplicate the effects of any color just by using colors at these peak sensitivities.

But...everyone's sensitivity curves are a little different. In the extreme cases, we call it color-blindness. Here are some color-blindness sensitivity curves. There, the mapping is different. If we have RGB output that looks exactly like a physical object to us, it might not look the same to them. (The two will neither look how we see it, or like each other.)

Ok, I went ahead and did a favor for the slashdot community and mankind. I took the fake colorized images and colored them back to the original infrared colors. You can see the results here. I hope this pleases the original story submitter.