From: Grace Taylor (gtay22@earthlink.net)
Date: 04/23/03-09:31:16 AM Z
on 4/23/03 9:31 AM, Don Bryant at dsbryant@mindspring.com wrote:
> Henry,
>
>> How do people modify the negative on screen to produce a suitable range,
> before printing via the transfer function?
>>
>
> First you can create an adjustment layer to adjust for contrast and or
> density.
>
> Second a transfer function can be converted to a curve and applied in a layer
> as well.
>
> Remember layers can be "turned off or on" to view your unadjusted image.
>
> In short there are a lot of ways to skin this cat. Get Burkholder's book for
> lot's of details.
>
> Finally avoid using the autolevels and auto anything to adjust your image as
> it usually doesn't give the best results.
>
> Don Bryant
>
>
Some comments on digital negatives and the transfer function. My limited
experience has been with digital negatives for Vandyke prints only, but I
have been successful in producing digital negatives for that process using
black inks on an Epson 3000 printer. In order to create negatives with the
right density for Vandyke, I began with Dan Burkholder's curve for platinum
and applied that to both an image (which on the screen looked perfect for a
normal B/W print) and a step tablet. The adjusted image was turned into a
negative (image and step tablet)and was printed on Pictorico OHP and used to
make a Vandyke print--which was terrible, but I had a starting point because
I could see from the printed step tablet where adjustment was needed. After
making some calculations for changing the densities in the step tablet, I
used the transfer function to create a new curve and printed an adjusted
image and step tablet as before. This also was not right, but the third
adjustment using the transfer function was right and I was able to get good
negatives and good Vandyke images.
This has not been without a good deal of frustration because there were
times when irregular banding appeared that I couldn't get rid of without
sending the printer in for repair. Also, I printed the same first negative
for the Vandyke process on three different printers--Epson 3000, Photo EX,
and Photo 700. Each Vandyke print had a different density, so a different
curve would have to be created for each printer. The 3000 looked the best,
so that's where I spent time adjusting the curve.
I don't know how one would modify a negative on screen to produce a suitable
range. The curve that works for the Vandyke prints looks terrible on the
screen so the only way I know to get the right density is by making a print,
then adjusting the curve.
I recently bought an Epson 1280 and am working on a new curve for that
printer. The one for the 3000 does not work for Vandyke on the 1280.
One other comment. Although the transfer function is accessed in the output
section of the print dialog box (Photoshop 7), I use it to build my curve
and save it in a folder for use later.
Grace
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