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Re: [QuadtoneRIP] I don't understand gamma, I guess.

2015-08-02 by Alan Vlach

Don’t know if gamma is your problem, but if you want to make sure your images are in gamma 1.8 go into Photoshop/Edit/ Color Settings and make sure the workspace you are using is set to gamma 1.8 and that you have checked all the boxes about profile mismatches. That way if you open an image and it is not gamma 1.8 you will be notified and asked if you want to convert it.


On Aug 2, 2015, at 2:19 AM, jp432r@... [QuadtoneRIP] <QuadtoneRIP@yahoogroups.com> wrote:

I think the problem I'm having has to do with gamma, but I don't have a solid grasp of what gamma does in each part of the environment I can't work out a solution. In fact I'm not really sure if it's the problem.

I'm making digital negatives for contact printing

I have carefully calibrated QTR using a gamma of 1.8. Step tablets print great. Scans with an embedded gamma of 1.8 print well, but the stuff I shot with my digital camera, post processed in Photoshop, inverted to negative, and printed using the calibrated QTR settings print very poorly. Very dark and muddy.

I don't really know the gamma of the files my camera creates, but I assume it is 2.1 or 2.2.
I've searched the web for info on converting a file's embedded profile from 2.x to 1.8 without luck.

I could start over and create a step tablet with gamma 2.1 and then recalibrate, but I've been working on this a week and I'm hoping to avoid that.

Does anyone have any suggestions on how to approach the problem?

Jeff




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