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I have two identical images content-wise, but they have different colors:

  • Image 1: an image in a blue color palette
  • Image 2: the same image with a hue shift (resulting in blue-green)

I am using the blue-green palette of Image 2 for many works. It is serving as my theme palette. Unfortunately, I noticed I did not save the hue shift value/number I used to create Image 2 from Image 1. I do however have Image 1 and Image 2 at least. The photoshop method I used to create Image 2 was:

Image > Adjustments > Hue/Saturation > ??

Where ?? denotes the mystery number I entered in the master hue UI. My task is to create Image 2 all over again from Image 1. I find it hard to do without knowing exactly what hue value I used last time. I could of course eye-ball it, but I'm going for precision.

Question: Is there a scientific and/or refined way to reproduce a hue recolor without knowing the number? Like I said, I do at least have the images. The only way I can think of is to start a labor-intensive process of systematically testing hex-color codes against the desired result (Image 2) and the new image (which starts as Image 1 but should result in being identical to Image 2)

  • 1
    Did you try use MatchColor? – LeoNas Mar 12 '18 at 13:24
  • 3
    It's a pity that you hadn't made an adjustment layer instead. That way the hue-saturation settings would have been saved in the PSD. – Billy Kerr Mar 12 '18 at 13:32
  • @Billy Kerr well just for good measure, how do I do that? I'll try to make a habit of that. – Arash Howaida Mar 12 '18 at 13:44
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Its is possible to retrieve this value if hue was really the only thing you changed. You can just open the image in some scientific package then convert it into HSL. Then just find the H difference of any pixel.

You can actually do this with the info window in photoshop:

  1. Set the info panel to display HSB color.
  2. Place your images on top of each other.
  3. Place a color sampler in your image. (or just pick same pixel over again with big zoom)
  4. Take note of the hue value in image 1
  5. Take note of hue value in image 2
  6. Calculate the difference. And that is your Hue change amount

If you have hard time opertaing the colorpicker and info window you can use the filter in other menu.

  • Image 1 had H: 201. Image 2 had H: 194. So the difference is -7. Hey that wasn't so hard! Let me make sure I didn't have anything else going on. I don't think I changed anything else. – Arash Howaida Mar 12 '18 at 14:35
  • @ArashHowaida The biggest problem is if you saved the image out in a lossy format like jpeg then you can not rely on each pixel being the same. – joojaa Mar 12 '18 at 14:38
  • I had to experiment a bit with the S and B values too, but now I have it so that I can't tell the difference. I'm pretty pleased with it. The images are .png, is that lossy enough to lose pixel consistency? – Arash Howaida Mar 12 '18 at 14:48
  • @ArashHowaida no PNG is lossless. – joojaa Mar 12 '18 at 14:51
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No this is not possible. if you have the original Before changing HUE files .. open that again.. and select a small portion (with no complex colors area) and apply U/S/B on that.

And here will the the procedure..

  1. first make a duplicate layer in original image (whether you've to use this layer or not.. but making a duplicate will always force you to save as psd.. Name it Original-Layer) ;)

  2. duplicate a small portion of some plane color (flat surface). (Call it A Layer) ---- side by side open the HUE changed image

  3. duplicate the same portion of some plane color. (Call it A1 Layer)

  4. zoom both of the same level

    4.1 Now duplicate again that selected portion (Call these layers as B and B1)

  5. now - desaturate both image (B and B1)

  6. on the original document B-layer press Ctrl+U .. and move (brightness slider only) and match the brightness first with (B1-layer).. you can keep checking the color value (because both are desaturated so only the brightness will in in color value.. whatever. .match the brightness first

  7. (note this brightness when matched)..on the slider position

  8. now remove the B and B1 layer

  9. on Layer A and A1

  10. Now more the slider of Brightness to the value what we found on Step-7.

  11. now start moving slider for Hue... very slightly.. and keep an eye on colors value

  12. once you've done with the Hue (note this value too)

  13. now apply the same values to the "Original-Layer" we duplicated on original doc

  14. there are 99% chances you will get the same result ... and now save these settings..

  15. there is no rule that you've set the first document HSB values are any ISO settings... a slight change should always be acceptable. But these new values can be saved and set as standards.

  • Use sbtract on the layer then you dont need to eyeball this. – joojaa Mar 12 '18 at 13:54
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This answer uses GIMP, but I'm sure that Photoshop has similar tools, perhaps under different names.

  1. Decompose both images to HSV or HSL.
  2. Take the extracted hue channels, and create an image which has them on two separate layers.
  3. Change the mode of the upper layer to "Difference".
  4. Flatten image.
  5. Look at the histogram, to check that there's a single sharp peak.
  6. (Optional) Scale to 1x1 to average all the values.
  7. Use the colour picker to extract the value.

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