W3C home > Mailing lists > Public > www-style@w3.org > December 1997

Re: RGB Color Notation

From: Mary Mooney <Mary.Mooney@Eng.Sun.COM>
Date: Tue, 2 Dec 1997 15:25:32 -0800 (PST)
Message-Id: <199712022322.PAA08984@hsmpka.eng.sun.com>
To: Steven.Pemberton@cwi.nl
Cc: www-style@w3.org
Steve, and org.

RGB hexadecimal is what we designers call the RGB notation that you are 
referring to.
Yes  - it is far from intuitive!
Yes -  it is cumbersome as we have to bring clients and staff members together 
to look at these color cubes to make decisions.

When my junior designers get together they have to print out the hex color
and a color patch.
There is no way that you can look at that notation and figure out
what the color is with just the hex numbers and color names are relative.

I would greatly appreciate it if you switched the color notation to
something that designers (who often pull together the front ends of these web 
pages, sites and applications) can use. Unfortunately HSL is not intuitive 
It requires that one know all the hue values. Designers really don't use
it. We work much better with RGB tri-stimulus values which are far more
common in notating color palettes on computers.

In truth, I and many other designers I know can tell approximately what a 
color looks like or is with plane #RGB values. I can also look at those values 
and know if it will work on a NTSC display or "WebTV" HSL can not provide
me with that intuitive knowledge. Since NTSC displays will be used for
web pages I highly recommend that RGB tri-stimulus #RGB values be used. For 
example; 145, 0, 88 is a dark reddish purple.  You can have the the style 
sheet just convert between the RGB hex and #RGB.
Don't use HSL, please it is far from intuitive for a designer. We might
as well just have the RGB hex.

I also recommend that you talk to Mr. Charles Poynton who wrote the
book on digital color that's poynton@poynton.com. He is also a 
SMTE fellow. You can find him on the web.

I hope to hear the good news that the CSS will do something for the 
production and design community who is largely responsible for the
proliferation of visual design on the web. 

I might add I'll be giving a half day tutorial on Color Management for 
Interactive Systems at CHI 98. I'd like to be able to drop the whole
issue of RGB hex due to ease of use with #RGB.

Remember the visual look of a Web page is the responsibility of the designer
and designers know - or are trained with #RGB. RGB hex is forced upon us by 
the industry. 
By the way it is hard for a web designer (graphic) to get a job here in
the States without enough knowledge of HTML to assemble pages. Often clients
are in one location designers in another and they'll conference call and
make changes on the fly. You can't move the page back into some tool. 

Thanks for your effort Steve!

Mary Mooney

> Sorry!
> Steven Pemberton
>   (Summary: By sending an email to www-style@w3.org, you can help
>   persuade the CSS group to include a more human-oriented notation for
>   colours than the RGB #FFFFFF style.)
>   You may already be aware of CSS (Cascading Style Sheets) a new part of
>   the World Wide Web that allow you to define the presentation of HTML
>   pages separate from the structure of the document. The new versions of
>   Netscape Navigator and Microsoft Internet Explorer already support
>   level 1 of CSS. (See http://www.w3.org/Style/css/). A working draft
>   for level 2 has just been released for public comment.
>   One part of CSS is the ability to assign colours to elements (like
>   backgrounds, font colours, and so on). Up to now HTML has only allowed
>   you to specify colours using a numeric RGB notation like #FF35EF, and
>   a limited set of names, and CSS has taken this notation over for the
>   specification of colours.
>   I am on the CSS committee, representing the HCI community, and my
>   opinion is that RGB notation is a poor notation from a usability point
>   of view: when confronted with a colour in RGB notation, it is hard to
>   determine what colour it is, and if you want to encode a colour, it is
>   next to impossible to do it without the use of a tool that does it for
>   you.
>   I have been trying for some time to persuade the CSS committee to
>   accept a more human-oriented notation.  Unfortunately the committee
>   consists for a large part of technologists, who don't see the need for
>   another notation when you've already got RGB, of implementers who
>   don't want any more work, of vendors who want to sell users tools to
>   select colours, and of people who say that they haven't heard any
>   demand from users for something easier to use (all these reasons were
>   used in meetings).
>   My latest, and last-ditch attempt (since CSS has gone public and will
>   be offered for ratification soon) is for HSL notation.  While not
>   perfect, it goes a long way to making colours more easily expressible,
>   while not increasing the work greatly for implementers.
>   You can see the whole proposal at
>   http://www.cwi.nl/~steven/css/hsl.html, with examples of colours and
>   their encodings, but in a nutshell, HSL looks like this:
>       * HSL encoded colours consist of three numbers: Hue, Saturation, and
>       Lightness.
>       * Hue is an angle from 0 to 360 degrees. It represents a colour from
>       the colour circle, with red=0 (=360 degrees), green=120 degrees,
>       blue=240 degrees. So for instance, since magenta is halfway between 
>       and blue, it is 300 degrees.
>       * Saturation is 100% for a pure colour, down to 0% for a shade of grey
>       (completely unsaturated).
>       * Lightness goes from 0% for no lightness (i.e. black), to 100% for
>       full lightness (white), with 50% being the 'normal' value for a
>       colour.
>   So for instance,
>           hsl(0,  100, 50) is red;
>           hsl(0,  100, 25) is dark red,
>           hsl(0,   50, 50) is a pastel red,
>           hsl(0,   50, 25) is a dark pastel red, and
>           hsl(240, 50, 25) is a dark pastel blue.
>   For the reasons mentioned above, the CSS committee have decided not to
>   include HSL colour specification, but have minuted that they will
>   publish the fact that it is an option, and if enough people ask for
>   it, it will be put in.
>   This is why I am writing. If you think that CSS should include HSL
>   (and note that this is now the only option: it is not possible to
>   propose another solution), you should send an email to
>   w3c-style@w3.org, giving your opinion about what you think of RGB, and
>   why you think that HSL would help make the Web a more human-oriented
>   place.
>   Thanks!
>   Steven Pemberton, CWI, Amsterdam; Steven.Pemberton@cwi.nl
> ------------- End Forwarded Message -------------

 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 "I think it is really important for the computer industry, or any industry 
which is using designers, to understand that design is a powerful tool that 
can be very effective in helping companies realize their corporate vision and 
goals. It is not a superficial surface treatment to be brought in an used at 
the end of a project."
     			-- Albin + Faris (SIGGRAPH 1993)

Mary Mooney			Sun Microsystems Computer Corporation
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Received on Tuesday, 2 December 1997 18:23:49 UTC

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