Yep - apply to the positive. Then use command I to invert. Add the
colorization layer in screen mode and print.
The triangle is a tiff file that has triangles with the proper
proportions in them. Just put your cursor on the triangle that seems
to work and read off the values. The one caveat about this and any
approach is DO NOT convert the file to match the working space. You
need to create a color settings file with color controls basically
turned off, otherwise when you bring the tiff file into photoshop, it
gets converted to the working space. You do not want to do a
conversion. Leave it in an unaltered state.
Say you find out that your printer's maximum UV blocking blend is R:
40 G:90 B:10. If you maintain the same ratio, then R:4 G:9 B:10
(same ratio, but smaller numbers) will block even more light, since
it has effectively had the saturation increased, i.e. the black ink
would kick in. Conversely, R:80 G:180 B:20 would block less light,
since the saturation is decreasing, i.e. less black ink would be put
down.
The easiest thing to do once you find the ratio by printing the
triangle is to make a gradient test strip with white at one end and a
relatively dark saturation at the other (small RGB numbers while
still maintaining the same ratio). Posterize it into 10 strips or so,
then print it at your minimum time to get a maximum dark tone at the
clear film edge. Pick the square that just prints paper white, and
then find out what color ratio pair that corresponds to. That will be
your color to use. Apply the curve to your file and colorize it and
print. Adjust the curve if needed.
My whole thought behind this approach was that it was simple and
close-enough. I started looking at all the in-camera negatives I have
managed to get great prints from, and notice that none of them were
perfect. This represented a way to get me consistent usable results
without getting too tangled up sensitometry. It is like saying - oh
heck, I'll develop this film an extra minute next time.
C
On Sep 12, 2005, at 9:16 PM, Michael Koch-Schulte wrote:
> So you apply the curve to the positive using this method, right?
> How do I
> break down the RGB ratio into the 0-255 scale? Say for example I
> want to
> adjust this method for Cyanotype.
>
> ~m
>
> link: http://www.alternativephotography.com/articles/art056.html
>
Received on Mon Sep 12 20:56:29 2005
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