Three Little Pig[ments]

From: Nicholas Bodley (nbodley@world.std.com)
Date: Wed Mar 28 2001 - 19:05:00 PST


Really well-done! The image is gorgeous. SO glad to see someone
finally say that red, yellow, and blue are not the primary colors. So
far, I haven't seen a reliable explanation of why they have been
described as such.

Our high school's stage had lights with, if you can believe it, red,
yellow, and blue filters. When you had just the yellow and blue
lights on, you surely did not get green. The school was not on a tiny
budget when it was built, either.

I would have wuch preferred an image with several more or less
"primary" colors (R Y G C B M) of objects in it, so just by looking
at the image, one could see how the individual resultant colors were
created. This image is great for greens and blues, but very poor for
reds and yellows. Nevertheless, this snack is a goodly part of a
meal!

You could have stated that black is needed because really-effective
subtractive-color dyes and pigments just can't yet be made; they're
far from perfect. Of course, the "last word" is spectral transmission
curves.

I recently went to a well-stocked art and craft store in Cambridge,
Mass. (Pearl Art and Craft) and tried to find brush pens with the
closest colors I could find to process yellow, p. magenta, and p.
cyan. (Process: Used for printing, more or less...) I ended up with
Marvy Brush marker 1500s, no. 22 yellow, no. 74 cyan, and no. 9 sort-
of-magenta. The last one has some red in it, but the three combine to
make some gorgeously-colored images! I was thinking watercolors, I
guess; you don't have much control over saturation with these. It
does make a difference, sometimes, which color you lay down first.
If you want to fool with the CYM color primaries, try buying a kit of
color inkjet printer refill inks.

Although cellulose acetate has been the transparency stock for
decades, what you get for a printable film might be polyethylene
terephthalate, better known in the USA as Mylar or PETE. I don't
think "acetate" is a truly non-specific term for transparency film,
although it certainly is used all the time with no thought about its
chemical composition. In an educational Web site, I think calling
things by accurate names is more important than in some other places.

Nicholas Bodley |@| Waltham, Mass.
Please reply to nbodley@alumni.princeton.edu
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Autodidact and polymath to some extent



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