Making a mask in Photoshop?

Discussion in 'Design and Graphics' started by generik, Feb 27, 2006.

  1. generik macrumors 601


    Aug 5, 2005

    I have 2 images that are similar and yet slightly different too, what I'm trying to do is to create an image mask that will match the common pixels on both images, but exclude the differences, how can I compare 2 images in Photoshop? :confused:

    Thanks :p
  2. ATD macrumors 6502a

    Sep 25, 2005

    I have a trick that will work if these two images are exactly the same, meaning that they are the same image, one has retouching and the other one does not. If you resized or rotated one this will not work. Take one of the images and place it on a layer on top of the other in the exact same position, do this on a copy. It does not matter which one is on top. Change the top layer to Difference. If they are in exact alinement the image will turn black, except the areas that are different, like the retouching. Flatten the image and turn it to greyscale. You may have to adjust the mid tones and highlights to bring it them out more. You now have a mask which you can place back into your original image.
  3. nagromme macrumors G5


    May 2, 2002
    What ATD said works. I use Curves to adjust the result so it goes to full black and full white, with as much softness between as I desire.

    And if you want to select the "same" parts and not the "different" parts, just invert the mask.

    (BTW, to make a mask from the B&W image you can just paste it in Quick Mask mode.)

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