: Can I change the color mode on which an Alpha channel value is read? In Photoshop, when I use the eye dropper to read a value on an alpha channel on a RGB, 8 bit per channel file, the

@Berryessa866

Your info panel is showing grayscale and CMYK values. Photoshop shows 8-bit* grayscale, opacity and CMYK values in percentages.

If you switch it to show RGB values (hit the eyedropper icon), it will show you the correct 0–255 range 8-bit values... If the image is grayscale (or your viewing a channel; which is essentially the same thing) all the values will be the same, so that works just as well.



Similarly with the color sliders, you can switch to the RGB sliders which will give you a 0–255 range (just set each slider to the same values again).



* Interestingly, Photoshop shows the correct 16 or 32-bit opacity and grayscale values, it's only 8-bit values that show as percentages...

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@Bryan765

I'm not sure if it's wise to be measuring any pixel values of an RGB source in CMYK values, but somebody could correct me on that.

There doesn't appear to be any way to get 8-bit alpha values as a value between 0 and 255. I'm afraid you'll need to do some maths to get a value in a range that suits you. For 0-255 you could do:

PERCENTAGE * 255 / 100




Edit:

I'd originally answered this question mistaking that you were confusing the k value completely for an alpha value, rather than seeing you'd isolated your alpha channel and were taking independent samples from it. I've updated the answer to reflect this but thought a paragraph I removed may still be of use to some on this topic. Particularly if you want the alpha value of a pixel when you're not using an actual alpha channel:


You can get an alpha value in the same palette if you use the dropdown
triangle in the info panel and change the mode to opacity in
the panel options of any of the dropdowns.

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