View Full Version : Photoshop and Gamma are no friends!

05 May 2010, 12:58 AM
Is it just me, or is Photoshop (CS4) unable to add a correct Gamma onto linear footage?
I have a client in the print business. I offered him a great benefit in realism of our 3D work if we keep the workflow linear.
After approval of some jpg previews (of cause WITH Gamma), I rendered out all elements in max as 16bit tiffs with 1.0 gamma.

I put them together to perfectly match the Beauty tiff, but when I added an Exposure Adjustment layer and set the gamma to 2.2, in oder to get the gamma correted Version (as approved) Photoshop did it completely different from Max. I get perfect result with fusion gamma 2.2 does exactly what max shows in the framebuffer.

Look at this image:

The image on the right should look exactly like the left one. PS failed completely. the dark areas are brightened up too much. the whole thing lost contrast.

What I ended up with was a selfmade curve to match gamma as close as possible, but hey this is not professional.

Is there a way to add correct Gamma in Photoshop?
thank you

05 May 2010, 09:20 AM
the main problem is that photoshop is an image editor program, not a compositing program like fusion. photoshop doesnt work in floating point, so this may be where the problem is occuring.

05 May 2010, 06:14 PM
Try Edit/Color Settings - you will find a button that says "more options", which will reveal advanced otions. There you can tell PS to blend colors using 1.0 gamma. Maybe this helps.

05 May 2010, 03:36 PM
I would never save a linear image (gamma 1.0) in a non floating point format. Those are not capable of holding all the information.

And you should change the gamma with the levels dialog. Just set the value of the center field to 2.2.
This should give you a better result.

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05 May 2010, 03:36 PM
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