• Q and A
  • Q&A - Vision


What color can be seen from the farthest distance?

How to Explain Colors to the Blind

Color Blind Consumers

Color Blind Preschoolers

Colors for online reading

Between what two colors does the human eye perceive the great contrast?

The Green Chalk Board 

Does the color of the eye change?

How color affects dyslexia

What color can be seen from the farthest distance?

Wayne De Jage:
White light. Incoming light from the farthest stars is percieved as white, although the color might be lacking in absolute purity as a result of the gaseous content of the star. Scientists evalute the spectrum generated by the star to determine its speed and its make-up.

How to Explain Color to the Blind

I am trying to put together a kit explaining colors to the blind. One way is through taste. The colors I am using are: red, blue, yellow, orange, green,white, balck and brown. Has anybody every thought of the taste of colors? Not that yellow is lemon, but what from the point of view of the mood of color, Yellow=happy, cheery, warm, etc. Please, if you know of any sources about that let me know. This email address is being protected from spambots. You need JavaScript enabled to view it. / Judy Geva

Judy, My sons are blind and I've found the book of poetry "Hailstones and Halibut Bones" by Mary O'Neill my favorite descriptions of color. I've seen your products and they're fun. Good luck on your quest.

Although it's a step removed from your needs, I've just been reading a book by Dr. Oliver Sacks called "The Island of the Colorblind." In it, he investigates, among other things, the terminology used by those who can see no color whatever to describe the world around them. A lot of this involves describing quality of light on the surface of whatever the object is, but the texture also plays a large part. I"ve also heard of using smell and sound as reference points for the color of things for the blind; rather like the correlations often made between colors and musical notes. That one alone might be a system to use, come to think of it. Good Luck. I look forward to hearing about your search and your results.

Also, The connection of smell (and taste) was mentioned in a little book called A History of Color by Manlio Brusatin. When I read it, it made so much sense I couldn't shake the truth of it. Brusatin writes about it quite elequontly, but I don't think I was swayed merely by his style. I haven't seen any scientific data to back it up, but I haven't looked for any, either.

mike milne
Wouldn't know how to explain. but isn’t it interesting that some hearing impaired can enjoy music through the vibrations. they use a sense other than hearing to relate to that which we hear....and isnt it interesting that both hearing and non hearing people experience these sensations through vibrations...wouldn't it be simple enough to put together a device that "saw" a color and then traslated it into a vibration....the higher the frequency of the color the higher the vibration....blind people could then experience nuances of color as well as just the basics.

Judy Geva, So, you're trying to put together a kit explaining colors to the blind? I'm curious. Are the people you're working with completely blind? Are they color blind? Blind - unable to see or detect contrast? - unable to detect edges, line, shape? Can any of them detect light-dark? Or - are their eyes transmitting zero data to their brain - no light stimulus-response? If the people you are working with are totally blind - have they been so their entire life? (didn't become blind from some event/accident/etc.? hence no memory of color?). Do these individuals have full use of other available senses - taste, touch (haptics), smell, hearing? Are the color/light processing abilities in the brains of these individuals operative? (eye-retina-optic nerve sensors are inoperative, but the rest works ok?) Have any of the 'blind' individuals you work with had experiences with 'color sensations' from other sensations? What do I mean(?): did they see 'stars' and color when they accidently ran into a brick wall or fell. did they sense / see light sensations when they were dreaming or when they accidently got shocked by an appliance ..etc.etc.? Obviously, it's of value to know the extent of these individuals sensory resources - their limitations - and so on, in order to be able to determine how color sensations might be inputted to them. * * * There are some correlative or analogical things you can do. Haptics (touch) equate to light and dark - stand in an empty room (with your eyes closed if you are able to see) - wave your arms around - unable to touch anything. That's black. Now move to a place with things - sensates - objects. Touch them. Feel them. You've moved from a blackness to a 'brighter' place. Hmmm. There's much more to this - but enough for now. Good / more rigorous analogs are there for you... I hope this moves along the lines you are thinking of. Regards, Mac

 Judy G.
More detail: People who are completely blind, from birth, especially children. I don't work with them, I manufacture for them Brailled chocolate gifts. I am looking to explain THE TASTE OF COLOR'S MEANING AND MOODS.

 Sally H
Years ago I worked with a blind young woman, and in a conversation I mentioned something about vanilla being brown (can't remember, but it was probably something along the line of my spilling vanilla and getting this brown stain on the cabinet or something like that)and she got very confused and said that she had always understood vanilla to be white. Boy did I have trouble explaining that!

Color Encyclopedia

Color Blind Consumers

I am a graphic designer with a boss who will insist that I keep in mind the percentage of poulation who are colorblind. This results in very monochromatic designs. I have no data to back up my argument for using colors -even though it seems every one else in our field uses colors freely. Can someone provide me with or show me where to get information that will sway the argument in my favor. Donna

Donna, Is your boss really fixated on tailoring your graphics work product to align with color blind people?Egads! He seems biased and a bit discriminatory if he only is concerned with that group. What about blind people? He needs to consider them too! I think you need to add texture toyour graphics - kind of a feel and touch thing. Fuzzy pictures, glossy pictures, sniff-n-scratch too. And if people are reading your work while in the dentist's chair and have fingers (and gums) numbed by xylocaine - he should consider providing 'readers' so the graphics can be verbally communicated. God forbid we get into people that are hard of hearing...bla bla bla. * * * Has he read about monochromats? dichromats 'n trichromats? If you're reduced to monochromatic images - isn't he sensorially depriving trichromatic people from enjoying the full extent of their sensory abilities - in hopes of tending to the dichromatic minority? * * * Tell him isn't not ethical to discriminate based upon color. * * * Tell me your boss is kidding. He can't be THAT silly! Does he turn the 'color' off on his color tv? Does he own a grey car? I have a custom "color-blindness" test chart you might like to hang on your wall. :-) Mac

Colorblindness affects one in ten adult males. It's extremely rare in women. The most common form of colorblindness is daltonism or a problem with red/green. This would be a problem with more equal value arrangements. So if you use high contrast even with red/green the text or image would probably be visible to those who are colorblind too. By the way, would you even use equal value red/green for text??? Imagine the optical vibration that could occur with the general public...unreadable at any distance!!!

Donna: That is a rather odd thing for your boss to focus so much attention on. Does he mean people who literally cannot detect color at all and see in black and white or just those who can't distinguish very well between close colors or just that they have no taste in colors? Maybe he (pardon the sexism) just prefers muted, monochromatic designs. A couple of suggestions: if he really believes that people can't tell the difference between colors, what does it matter which you use? So long as the light and dark of the design works in black and white (think of a conversion from color to b&w) if the colors, too, are pleasing and dynamic, everybody wins. Also, Dr. Oliver Sachs, the noted neurologist and author, has just published a book called The Island of the Color Blind. It's about, you guessed it, an,island on which most of the inhabitants can't detect color. He also goes into how rare this is in most societies, so he may even have specific statistics as to total color-blindness and commonplace degrees of it. Bottom line, though, he's the boss, so, probably, what he says, goes, eh?

stephanie newman
Daltonism was first found (or brought to our attention) by John Dalton, an English scientist. Daltonism could be referred to as colorblindness.

 Carol Kaufman-Scarborough
I am currently recruiting people who have some level of color-deficiency in their vision. My survey takes about 10 minutes to do, and asks about problems that color-blind persons have had with products, labels,advertisements, and shopping in stores. If you are interested, please email me and I can send you a copy of the survey. I would appreciate any ideas for finding color-blind persons to participate in my study. My preliminary study results were presented at the Public Policy and Marketing Conference in Arlington VA in June 1998. Thank you. Carol Kaufman-Scarborough, Ph.D. Associate Professor of Marketing Rutgers University School of Business 227 Penn St. Camden, NY 08102 Email: This email address is being protected from spambots. You need JavaScript enabled to view it. Fax: 609-225-6231

Colorblind preschoolers

I have a three yr old son who I think may be colorblind. It runs in my husband's family. My problem is that most vision tests have numbers that you are supposed to recognize to determine if you are color blind or not. My son, however, is not old enough to know what a number is. Are there any tests out there for preschoolers? Susan

I deal with preschoolers every day and often am the first to recognize "color-blindness" (which is usually not color-blindness but specific- bands- of -color blindness. The simplest way to find out if there is a perceptual difficulty is to take a mixed box of several sets of colored pencils (the 24--36 different color sets) and ask your child to show you a pencil that is the same color as "this one." You can notice where (if at all) the difficulty is and whether or not your child has any reluctance about the activity (which indicates whether or not color is causing trouble in day-to--day life). Hope this helps. If your child is color-blind, please teach him that it's not a tragedy--we all ask each other for help in many different areas and color "correctness" can be one of those. The children here have no problems helping their color-blind classmates.

Susan, If he knows his colors, you might show him single colors on cards or with crayons and ask him to name them. The most common form of color blindness is red/green mixup. A rare type is blue/yellow mixup. Another idea is to have him match about equal value colors of one set of colors to equal value colors of another set -- each randomly set before him. We'll be interested what you come up with.


Colors for online reading

This email address is being protected from spambots. You need JavaScript enabled to view it.
I'm a writer who's interested in writing online. I was thinking about interactive novels or serials. Either way, the reader would be spending an extensive amount of time looking at a computer screen. So, what colors would one recommend for both the letters/numbers and the background? So far, I've heard that a soft green on a light green background works best...is that true? Any responses would be greatly appreciated.

Cynthia Wegner
I have to agree. Green seems to be a soft color to read. Blue just doesn't cut it, as this net page shows. I wouldn't go so far as to put two greens together for background and lettering, but maybe it would work.

Jill Morton - Color Matters
Readability on line is a critical issue and it's great that you're questioning your colors. From what you've described, soft green on light green will not provide enough contrast. As for green, some say that it's the most restful color for the human eye, but if there's not enough conrast , it won't work. The issue is one of contrast, dark type on a light background, or light type on a dark background.

Between what two colors does the human eye perceive the great contrast?

The human eye does not distinguish all colors the same. Between what two colors does the human eye perceive the great contrast?

Kaliman, Black and White are special case colors. Grab a chart of the frequency spectrum. Select any one frequency. 600nm., 900 nm, whatever you wish. Can you select a specific frequency that is White? How about a frequency that is Black? Swain mentioned Orange and Blue as being a highly contrasting pair. (oh, I suspect the baby factor is irrelevant). If you're looking for single frequency visible colors, Yellow and Indigo would be the greatest constrasting pair. Yes? If you're looking for multi-frequency visible emissions, then, of course, Black and White would be a pair with the greatest contrast. Regards, Mac

Christopher Willard
Are you interested in perceving contrast as a personal and phenomenological expience -- then I'd say the perception of highest contrast is somewhat a matter of opinion and preference, or are you interested in the greatest compensatory difference the lens has to make to focus different colors, then we are looking at opposite ends of the spectrum such as blue and red. I suppose too, if you define which type of contrast you mean that would help, whether, value, hue, saturation, or all three.

Chris, I agree, defining what type of contrast would be helpful. Cheers, Mac

The Green Chalk Board

A number of years ago, a Dr Harmon from Texas gave a presentation on the development of the green chalk board. The basic concept was that this was the only color we see precisely in space - reds are closer; blues are farther away. Purportedly, this was due to the physiology of the eye and the arrangement of the color receptors. Any research on this? Peter Wood

Like I don't have enough to do....well color pursuits are my drug, so here goes: very briefly put: we remember when newton dispersed white light through a prism the colors separated. The reason for this separation was that the prism refracted more of the shorter wavelengths than it did the longer wavelengths. We have a simple lens in our eye this is a very simple optical instrument, much like the prism is a simple optical instrument. Thus the light passing through the lens is affected in much the same way the light is affected when passing through a prism. The lens refracts more or the shorter wavelengths than the longer, ie. the angle of exit for blue is greater than the angle of exit for red. Simply put the lens must change shape slightly when focusing red compared with blue. Red is focused with a greater distance between the lens and retina, blue with a nearer distance. If you recall the sequence of light when dispersed through a prism, green is roughly in the middle of the spectrum, nearer to blue in my recollection though, for in the middle is where red and green mix to yellow. Spectral distrubution for a broadband green shows a peak of about 500 nm . It seems then the chalkboard chatter is suggesting because green is in the middle, ie. either less near edges of the spectrum or less suceptible than red or blue to the bending of waves that he is making a case that it is the most stable color in space (whatever the heck that even means!). It doesn't add up to me though. I woul d like to see the documentation on that lecture, sounds interesting but smells like something made up by someone who doesn't understand the eye lens very well. NOTE I've not even talked about the retinal rods nor the opponent process of coding in terms of red/green, yellow/blue, black/white which would probably blow his theory out of the water! I'm interested in other thoughts on the subject....

 Jill Morton- Color Matters
Thanks Mac, Peter, Chris, dmccoy ...now you've got me rethinking the larger issue and digging into my files. No answers for whether the lens changes shape but I did turn up some good web sites that explain the near/far issue. From the Exploratorium web site at http://www.exploratorium.edu/xref/phenomena/aberration_-_chromatic.html (this url is correct, _-_ is part of the address) and http://www.exploratorium.edu/xref/exhibits/rainbow_edges_in_your_eye.html "Like a prism, the triangular edge of a lens bends blue light more than red light. Blue light is therefore brought to a focus closer to the lens than red light resulting in a color distortion called CHROMATIC ABERRATION." Also, more info from "The Joy of Visual Perception: A Web Book" by Peter Kaiser (Ph.D. in Experimental Psychology) at http://www.yorku.ca/eye/ Link to http://www.yorku.ca/eye/red-blue.htm

Does the color of the eye change?

Can an adult individual's eye color change from green to blue on an hourly or daily basis?

The eye color can change depending on the light. For example, yellow light can make blue eyes look green. Since the quality of light changes throughout the day, ones eye color may appear to change.

My hazel eyes change with both my mood and with the color I am wearing.

I suppose 'eye color' can change in a few seconds if you have the right shade of contact lenses. :-) From what I've seen :-) iris color changes require months or years to change significantly. Well, come to think of it, check out the color of a newborn infant's eyes. The iris color can change quite rapidly as they move into infancy. There too, are those with two different colors of eyes...say a left brown and a right blue. Statistically, that only occurs in 1 out of 300,000 people. Then again, if you read any books by Jensen, et.al. you will find mention of many things that alter iris color... Happy researching... Regards,

Color of the Iris (more information)

Mac: The coloration of the iris changes as the baby grows (and if you are really observant - a few other places on a person kind of change color too). Pigmentation of the iris occurs pretty quickly. It kinda settles in....some get brown, some blue, on and on. Oh, if you sit on a street corner and look at about 300,000 people, you'll find that one of them (statistically) will have two distinctly different colors of iris's. (Yes, in the same head!) Maybe one will be a brown iris, the other a blue one. Weird! But, true. Maybe they had a mixed diet? Maybe they chewed a hamburger on the left side of their mouth and ate blue crayons on the right side of their mouth? I dunno. If you have time and you find one of those weirdos, follow them around for about 20 years. I would like to know if their iris color stays that way all of the time. :) * * * Did any of you ever hear of the term "Iridology" ? It's old stuff. It's the 'science' that studies iris color, shape, condition, and patterns. Did you ever hear of the term "Sclerology" (That's the cute little white areas on your eyes.) Maybe you'd enjoy poking around in the 80 year old literature on that too. * * * Did you ever think that eye-iris color just might be really genetically-driven? Uh, I hope so. Did you ever think that even though it is genetically driven, it might be influenced by an individual's exposure to the environment? diet? air? food? stress? on and on? If a friend of yours was ....heaven forbid...poisoned over a period of years say with arsenic and you were able to gaze so so closely into their eyes (iris's) would you be suprised if you could see a change in the iris coloration? If they drank Pepto Bismol for 20 years, would it suprised you to know you could see a visible sign of that chemical abuse in their iris's? Did you think that all of the blue-eyed people might have different color preferences than the brown-eyed people? Would it suprise you if there was no difference at all? * * * If someone has the interest and time and really studies the iris perhaps we will learn the answers to some of these questions. Might you be the person that dares to do that? Regards, Mac


How color affects dyslexia?

Check out studies by Irlen. Certain colors and tinted overlays help with some forms of dyslexia. Helen Irlen did the studies. Searcg yahoo for irlen.

In some studies it has been proven that color-tinted glasses help dyslexics read long pages of writing with no problem. Everyone has a different color, and tests are done to see which color suits you best.

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