Solve : Photoshop Contrast - Please help?

1.	Solve : Photoshop Contrast - Please help?
Answer» Hi, Does anybody know exactly what PHOTOSHOP does to an image when you reduce the contrast suing the contrast adjust toll. OBVIOUSLY the difference between the darkest part of the image and the lightest part of the image is reduced but is there an equation which would let me quantify this reduction. Any help or tips would be really appreciated. Thanks, GillCan you give us some more information like: WITCH OS do you use? Is it adobe photoshop?,Witch version? Quote from: Jonas Wauters on April 12, 2007, 06:31:26 AM Witch OS do you use? Is it adobe photoshop?,Witch version? It doesn't matter what OS it is, Photoshop as an executable has the same action for contrast on all OS's, because the program itself doesn't change. As for an equation for the contrast, I don't know exactly, and I think you might struggle to find one, but what it does is average out the total of all the greyscale shades (as if your image was in grayscale), and then gradually applies the grey total to the colour image you are lowering the contrast of. Effectively you could do the same thing by creating a layer of the average grey above that layer, and then adjusting the opacity. 1% opacity = -1 contrast, 70% opacity = -70 contrast, etc. Hope that helps.Thanks for the replies. That's exactly what I needed to know. GillNo problems, glad it helped.

Answer»

Hi,

Does anybody know exactly what PHOTOSHOP does to an image when you reduce the contrast suing the contrast adjust toll. OBVIOUSLY the difference between the darkest part of the image and the lightest part of the image is reduced but is there an equation which would let me quantify this reduction.

Any help or tips would be really appreciated.

Thanks,

GillCan you give us some more information like:
WITCH OS do you use?
Is it adobe photoshop?,Witch version?
Quote from: Jonas Wauters on April 12, 2007, 06:31:26 AM

Witch OS do you use?
Is it adobe photoshop?,Witch version?

It doesn't matter what OS it is, Photoshop as an executable has the same action for contrast on all OS's, because the program itself doesn't change. As for an equation for the contrast, I don't know exactly, and I think you might struggle to find one, but what it does is average out the total of all the greyscale shades (as if your image was in grayscale), and then gradually applies the grey total to the colour image you are lowering the contrast of. Effectively you could do the same thing by creating a layer of the average grey above that layer, and then adjusting the opacity. 1% opacity = -1 contrast, 70% opacity = -70 contrast, etc. Hope that helps.Thanks for the replies. That's exactly what I needed to know.

GillNo problems, glad it helped.

Solve : Photoshop Contrast - Please help?

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