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Inspiring
October 11, 2017
Question

Using Curves to match values from Color Sampler Tool

  • October 11, 2017
  • 2 replies
  • 2249 views

I used the Color Sampler Tool to place a target on the skin tone I want to match to (sample #1) and I place a target on the skin tone I want to change(sample #2)

I create a Curves Adjustment Layer clipped to the layer I want to change the skin tone of

1. What gets entered into the Input and Output fields for the Curves to match the skin tones? The sample I want to use shows R=209/209 G=165/165 B141/141

Thanks in advance!

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    2 replies

    Participating Frequently
    October 12, 2017

    First ensure that your Color Sampler Tool is not set to Point Sample.

    If you have a low resolution photo, use Sample Size: 3 X 3

    If you have a high resolution photo, use Sample Size: 5 X 5 or more

    When selecting samples, ensure that they are not too similar in value/brightness.

    Selecting from shadow, midtone and highlight as davescm​ mentioned above.

    Once you have selected samples in each images, you will have 6 colors.

    If you are working in RGB you will have:

    • Image to be adjusted: R1G1B1(highlight), R2G2B2(midtone), R3G3B3 (shadow)
    • Image with target  color: R4G4B4(highlight), R5G5B5(midtone), R5G5B5 (shadow)

    Now you are ready to match the color using Curves:

    In the Curves settings, go the the Red Channel.

    Cilck 3 random points. For each point set the input and output values:

    • Point 1
      • Input: R1
      • Output: R4
    • Point 2
      • Input: R2
      • Output: R5
    • Point 3
      • Input: R3
      • Output: R6

    Apply the same method in Green and Blue Channel.

    After this, you should not be dragging the points around.

    If you selected your highlights, shadow and midtones carefully, you curve will not be jagged.

    [Don't forget to click my star ✪ if it's helpful. ]

    Inspiring
    October 12, 2017

    I ended up using the hand with the finger to click on the area of the image that I want to adjust on the curve and I dragged either up or down to adjust the R,G,B values of the layer that I want to adjust.

    1. Is this a sufficient/accurate alternate way choosing anchors on the image I want to change?

    2. While dragging at the selected point and watching the values in my Info Panel I see the values for my second column numbers changing for both the layer I am changing, and the layer I am trying to match to. Why are the values changing for the second column I’m trying to match my new layer to? The Curve is clipped to just the layer I am trying to adjust. Shouldn't the Curve not be affecting this area of the image?

    Thanks everyone!

    Participating Frequently
    October 12, 2017

    I'm not certain that this is what you are looking for, but...
    Using the hand tool in Curves, hold shift+ctrl and click on the color you want to locate on the curve. (In the screenshot I clicked on the sky)  Each color channel will be marked (as shown in the red channel).With each channel active change the output value to the RGB value of the replacemnet color.

    davescm
    Community Expert
    October 11, 2017

    Hi

    Use more than two points - preferably three or more on each taken from similar shadow mid and highlight areas of the skin

    Then In curves switch in turn to Red - then Blue  then Green, each time adjusting the curve by dragging it , whilst watching the info panel, to match the pairs of points points as closely as possible. Don't be tempted to make the curves too jagged to get an exact match - it will look worse than just a close match with a smooth curve

    Dave

    Inspiring
    October 11, 2017

    1. How do you determine where to drag on the curve? I’m currently dragging somewhere around the middle of it in each of the R,G,B channels.

    2. To simplify this for now, I made two sample points, #1 is where the skin needs to change, #2 is the skin that I want to match to. I am now looking at the Info Panel and just dragging up on the middle of the curve until the values in the second column in the #1 area for the R,G,B values match the R,G,B values in the #2 area. Is this the correct way to do this??

    Thanks!!!

    davescm
    Community Expert
    October 11, 2017

    Dragging the middle will work for one pair. More than one pair of points will help you with where to drag the curve to match the "shape"

    Dave