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hward
08-22-2009, 10:45 PM
MY IMAGE(S):
http://www.wetcanvas.com/Critiques/upload_spool/08-22-2009/39128_image002.jpg


GENERAL INFORMATION:
Title: Computer Art, Drawing Subtraction
Year Created:
Medium: Pencil
Surface: Paper
Dimension: 3 x 6
Allow digital alterations?: Yes!

MY COMMENTS:
I copied an egg from a drawing book. I liked my egg OK, but I wanted an objective measure of the accuracy of my copy. Having a webcam and 18 years of programming experience, I wrote a program which displays the difference between a copy and an original. This is a screen shot of the program, after I ran it on my egg.

MY QUESTIONS FOR THE GROUP:
Is the meaning of the red and green colors clear from the screen shot?

La_
08-23-2009, 05:19 AM
well that's interesting ... hmm ... many uses come to mind ... would it be better to use non compliment colors? maybe red and yellow ... only because i find it easier to see the subtle variations in orange as compared to the browns when mixing red/green ...

la

hward
08-23-2009, 03:38 PM
I will try your red/yellow idea today. Thanks for the suggestion.

With regard to your question about complementary colors, the answer is "no", because computer colors do not mix like paint.

Computer: red + green = yellow (additive mixing).

Paint: red + green = brown (subtractive mixing).

In my program, I added a little blue, to change the yellow to white. So white (not brown) indicates a perfect match between the copy and the original.

See the color mixing charts in the Wikipedia articles http://en.wikipedia.org/wiki/Subtractive_color and http://en.wikipedia.org/wiki/Additive_color