Re: A dumb question on Digital Negatives...

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FDanB@aol.com
Date: 09/21/02-08:54:29 PM Z


Mark Nelson said in his message...

>This may be a dumb question, but I would be interested in knowing if people
>are applying the adjustment curve to their Photoshop file before they invert
>the image to a negative or after they invert the image to a negative.
>Especially interested in Dan's response.
>
>I assume it would take a different curve for one workflow or the other. Any
>reason one would be better than the other?

Not dumb at all.

It's generally better to apply the adjustment curve to the positive image
rather than after inverting it to make a negative image. There are a
couple reasons why.

As you tweak your curve, it's much easier to think in "normal" positive
terms if the image (and step tablet that you wisely included with your
image) don't print properly. To lighten an area of the image, you raise
that portion of the curve; to make a tone print darker, you lower that
portion of the curve. Very logical. (Note: this is assuming you have
Photoshop curves set up with blacks on the left and whites on the right.)

If you are using one of the spectral density methods (making negatives
with an orange/red color) like I do for platinum, it's crucial that you
perform the steps in the right order: curve, invert and colorize. If you
mistakenly colorized and then inverted, you'd get a bluish negative that
would pretty much be like printing with no negative at all on a UV
sensitive medium like platinum.

In workshops I'm now giving students a CDROM that includes several inkjet
negative templates. Using Adjustment Layer Sets, students can apply the
curve, invert the image and colorize it...all with ONE click of the
mouse! Very cool and easy. I don't have these templates on my site
because they are too big to download. If I come up with a scheme to make
them available far and wide, I'll let you know.

One final nerd note: in an ideal world, it's better to apply curves to
16-bit images, thereby minimizing the tendency to band. The downside is
that you can't use nifty Adjustment Layer Sets with 16-bit images.

Hope this helps!

Dan


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