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Re: color orange

From: Anne Pemberton <apembert@crosslink.net>
Date: Wed, 25 Aug 1999 12:20:58 -0400
Message-Id: <3.0.5.32.19990825122058.007c8a40@apembert.pop.crosslink.net>
To: "Leonard R. Kasday" <kasday@acm.org>, "jonathan chetwynd" <jay@peepo.com>, "Kynn Bartlett" <kynn-hwg@idyllmtn.com>
Cc: <w3c-wai-ig@w3.org>
Len,

	Thanks for an informative explanation of things I sorta understood but not
really. In working with both screen and print with children's art
(illustrating the meanings of their new words), I have also run into the
problem with colors that aren't "true" when printed. A perfect "turquoise"
was on the screen, but the print out was a muddy "antique" blue streaked
with a bit of green. It did not improve much when it was scanned, smoothed
and printed on a "better" color printer. From your note, I suspect my
problem is the reverse of the orange problem. 

	Thanks again for your explanation,

				Anne


At 11:05 AM 8/25/1999 -0400, Leonard R. Kasday wrote:
>Hi Jonathan,
>
>Interesting question about why orange is dull on PC Monitors.  The answer
>lies in physics and visual perception.  I'll get to that in a moment.
>
>First let me see if I understand the relation to accessibilty.  You're
>concerned with designing web sites for non-readers, so you want to pack in
>as much meaning as possible without words.  Since color is a way to convey
>meaning you want as large a gamut as possible.  So limits on Orange are a
>problem.  Is that your concern?
>
>It occurs to me that there are other accessibility concerns too regarding
>color.  Since color carries meaning... at least subjective meaning (joyous,
>sad, exciting, etc) I would guess that some blind folks would want to know
>about the color scheme, in at least some situations.  That brings up the
>question, when you're describing the color scheme, whether to name the
>colors, or describe the mood you're trying to convey (e.g. "joyous", "sad",
>"exciting" etc.) or both.  Another accessessibility issue in the larger
>sense is that the meaning of a color is context and culture specific. Plus,
>of course, there's the legibility of colored text against colored
>backgrounds, like what they're looking at at University of Toronto.
>
>Anyway, here's why orange is so dim.  PC monitors combine red, green, and
>blue light to make white.  To get any color, such as orange, you actually
>dim one or more of red, green, or blue.  For orange, in particular, you
>turn off blue and dim green quite a bit.  (You can make it brighter by
>adding blue, but then it also gets paler.)  So orange is a lot less bright
>than the full brighness white.  It's also less bright than other colors.
>For example, it's dimmer than yellow which doesn't require you to dim green
>so much.
>
>(Note to people who are used to mixing paints: what I'm saying  sounds all
>wrong to you because rules for mixing paints are different than rules for
>mixing lights.  Technically, it's subtractive color mixture vs. additive
>color mixture).
>
>Your eye (actually your eye and brain) judges brightness by comparing it
>with the surroundings.  So if you you have orange in the context of other,
>brighter colors it looks dim by comparison.  Or if the whole background is
>orange, it's dim in relation to the room surroundings.  Like I say you can
>add blue to make it brighter, but then it gets paler.
>
>So if you want to make the orange brigher make the area small and surround
>it with dark colors.  Samples of color combinations are at
>
>http://astro.temple.edu/~kasday/color/colortable.html
>
>In particular, you can see orange and other colors against different
>backgrounds in fig. 2.  Note that orange looks different depending on
>whether is the big area or a text against a big area; and what the
>background is.
>
>By artistic standards, what I've said is pretty simple.  There are more
>complex techniques that artists use when they are painting highlights,
>reflections, and lights.  You can find descriptions in books on  advanced
>oil painting techniques, for example.  For example, you can make a surface
>look brigher by surrounding it with a dark color and then smoothly shading
>that surround to light again.  A good way to make a moon glow.
>
>Just remember though that the way you get colors on a PC are different than
>how you get them mixing paints so you'll have to ignore what the books says
>about mixing colors.  Just look at the final colors they wind up with.
>
>Len
>
>At 08:18 AM 8/24/99 +0100, jonathan chetwynd wrote:
>>Perhaps you remeber the days when snooker was in black and white on
>>television?
>>
>>It was not very satisfactory, nor accessible.
>>
>>without a commentary, almost useless.
>>
>>So perhaps you could answer my question as to whether your screen has a
>>vigorous and acid orange.
>>
>>Answers from any and all members would be appreciated.
>>Color is a complex problem, words, perhaps not the best examplars.
>>
>>Perhaps someone out there can make my oranges sing.
>>
>>
>>jay@peepo.com
>>
>>a www for those learning to read.
>>
>>Please send us links to your favourite websites.
>>Our site www.peepo.com is a drive thru.
>>When you see a link of interest, click on it.
>>Move the mouse to slow down.
>>It is a graphical aid to browsing the www.
>>We value your comments.
>>
>>
>>
>>
>>
>-------
>Leonard R. Kasday, Ph.D.
>Universal Design Engineer, Institute on Disabilities/UAP, and
>Adjunct Professor, Electrical Engineering
>Temple University
>
>Ritter Hall Annex, Room 423, Philadelphia, PA 19122
>kasday@acm.org        
>(215) 204-2247 (voice)
>(800) 750-7428 (TTY)
>
>
Anne L. Pemberton
http://www.pen.k12.va.us/Pav/Academy1
http://www.erols.com/stevepem/apembert
apembert@crosslink.net
Enabling Support Foundation
http://www.enabling.org
Received on Wednesday, 25 August 1999 12:37:42 UTC

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