In the epistle "Re: B&W Art Copies" scribed 03-30-98 09:45,
Karen Wattie did thus proclaim to Bob Dial:
Karen 
KW> Gee, where I come from we learned that primary colors were red blue and
KW> yellow, and that blue and yellow make green.  That makes far more sence
KW> to me since I can duplicate that.  I see no way on earth that red and
KW> green can make yellow.  Now I will have to dig around in the basement to
KW> see if I can find what my manual has to say on that subject  :(
If you shine a red spotlight and a green spotlight on a
white screen, the result is yellow! If you shine red and
green light at a blue screen the result is theoretically
black. The primary colours of light are different from the
primary colours of pigment.
Light:  Red - Green - Blue
Pigment:Red - Yellow - Blue
Secondary Colours:
Light:  Cyan - Magenta - Yellow
Pigment:Green - Purple - Orange
It has been so long since I dealt with pigments that it took
some pondering to remember! Photographers and computer graphics
artists deal with light, so one thinks in RGB and CMY. Even
when dealing with printing companies, it holds. If you view
a colour picture in a newspaper or magazine with a magnifier
you will see CMY inks along with black(K). Thus in Photoshop,
you are able to work in either an RGB or CMYK colour-space.
In the darkroom, when you make your first test print and
evaluate it, you may find that it is too blue. Now here
it gets confusing to be beginner! To get rid of the blue
cast, you turn down the yellow knob! Since you are working
with negatives you do the opposite of the obvious. It is
anything but intuitive, but one quickly learns.
With my 3-D work, I do all my painting of objects by mixing
colours with RGB sliders. R255, G160, B000 gives a very nice
gold. R190, G000, B128 gives a rich royal purple. R255, G190,
B160 gives a warm beige. I am at the point that I can now
visualize the colour I want and just dial it in. Of course
the program lets you see the colour you are getting as you
slide the sliders, so you can mix by sight as well.
larry!
... When I was a boy, we had to view our monitors by candle-light.
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