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Albdamned
Participating Frequently
September 7, 2023
Question

Comparing bitmaps to assign color to pixels

  • September 7, 2023
  • 1 reply
  • 961 views

Is there a way to compare two different black and white images (png). These two tone images that are exactly the same dimensions. Is there a way to have adobe compare the two images (perhaps as layers), and assign a color based on the values comparision? I would also like to distinguish between the pixels that are different, based on how the difference layers (is it white and black, or black and white).

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    1 reply

    c.pfaffenbichler
    Community Expert
    c.pfaffenbichlerCommunity Expert
    Community Expert
    September 8, 2023

    Please post the images. 

     

    The Blend Mode »Difference« comes to mind. 

    Edit: 

      A
      AlbdamnedAuthor
      Participating Frequently
      September 10, 2023

      Thanks for your post. I will try this out with a red and green pic layer. I should have time later today. I would be happy to give jpeg versions of them, as BMP is not supported. The only reason I mentioned the bmp is the pixel map nature. I am more interested atm in getting the process down at the moment. I can give you examples that would work as a fun place holder. Both of thes images are blown up (102 times), and the grey has been dithered black. Based on 4 possible combination of overlapping pixels (black/black, black/white, white/black, white/white), I would like 1 of 4 colors.

      A
      AlbdamnedAuthor
      Participating Frequently
      September 12, 2023

      For the second case I forgot to change the name of »x2« – the actual Blend Mode is »Linear Burn« (edit) and the two Curves Layers are not identical. 


      I think the smart object is the ticket. The way I was thinking was to give different values (all with just cyan) to the 3 colors (Black from layer 1, black from layer 2, and white from either layer), and then use the conentration  to determine the colors. I have created a truth table that would take these 6 values, and convert it into the desired colors. Please note the colors in the table are not meant to be considered the colors I am using (excel does weird things with colors). I will try the guidance you have given.

       

      I was trying to index the colors but it resulted in photoshop taking liberities that compromised the result. (with the truth table, you can look at 2 pixels, and see what the result should be).

      I appreciate your efforts, and would like to apologize if my verbiage is off or I am being difficult with my exactness. I would like to explain that I have a background with philosophy and computers, (If it wasn't obvious with the truth table lol). I have a strong understanding in "if this, then that", which is 99% of what a computer does. I can usually navigate photoshop but becomes frustrated when there isn't a more code level adjustments like this. Ideally, I wish I could look at a spreadshead and enter formulas to cause the changes. If there was an easy way to convert a png to a CSV and vice-versa i would be set lol.

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