Photoshop Contrast vs. Paper Grades

What's the approximate equivalent in photoshop (Contrast control) to going from say a grade 2 to a grade 3 ...4...5 in graded paper or contrast filters? 5, 10, 15 per cent? Is it linear? Thx.

On 23-Jan-05 16:21, Alan Smithee wrote:

What's the approximate equivalent in photoshop (Contrast control) to going from say a grade 2 to a grade 3 ...4...5 in graded paper or contrast filters? 5, 10, 15 per cent? Is it linear? Thx.

I know what you're asking but I don't have the answer. It's been 14 years since I used Kodak Polycontrast paper. I found the technical aspects of the filters, I guess it's up to you to determine the PS equivalent. Post back if you figure it out.

http://www.kodak.com/global/en/professional/support/techPubs /g4037/g4037.jhtml?id=0.1.16.14.30.48.14.4&lc=en

Scroll down to: ISO Paper Speed and Range

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JD..

On 23-Jan-05 16:21, Alan Smithee wrote:

What's the approximate equivalent in photoshop (Contrast control) to going from say a grade 2 to a grade 3 ...4...5 in graded paper or contrast filters? 5, 10, 15 per cent? Is it linear? Thx.

Why is this important to you?

I used to print from 4X5 Polaroid negatives onto Kodak Polycontrast paper. I leaned to underexpose the Polaroid just a little and then overdevelop it by 30 seconds. Keep in mind, Polaroid negative. Type 55PN.

Then I could print from that negative with no filter. If I needed a little more contrast, then I could use the 2 or 2.5 filter.

IN PS7, I just do it visually on the screen.

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JD..