How to perfectly match color between two photos using curves

If you want to change colors in your photos, you may find color inspiration lying in other images. If you want to copy the exact color from one image to another, Colin Smith from Photoshop Cafe has a tutorial to help you do it pretty quickly and accurately. He uses a Curves adjustment layer and works in Lab mode, and he teaches you how to apply this technique to flawlessly match colors between two images.

For his photo, Colin finds inspiration in nature. He wants to turn the model’s yellow shirt into a blue one so it matches the color of a parrot fish. So, he samples the color from another photo, showing a parrot fish.

To begin, switch from RGB to Lab Color. Go to Image > Mode > Lab Color and make sure not to flatten the image. Everything will look the same, only the channels won’t be Red, Green and Blue anymore, but L (lightness), A (green-red) and B (blue-yellow). Now, go to Window > Info to get an info panel, which will give you the color values.

Next, select the Eye Dropper tool. Before you sample the color, choose the sample size. You can go with 5 by 5 or 11 by 11 average, it doesn’t have to be a point sample. Within the Eye Dropper tool, choose the Color Sampler tool. Click on the source image to get a color sample, and you’ll see the color values in the Info panel. Then, click on the target image to get the sample of the color you want to change. What you need to do is transfer the values from the source image onto the target image, which takes us to the next step.

When you’ve sampled the colors, it’s time to make a selection of the area you want to change. Colin uses Color Range selection, but I guess you can use any method you like. Once the selection is done, it’s time for the following step.

Now, add that Curves adjustment layer I mentioned earlier. Within this layer, make sure to click on the Finger tool.. Hold down Ctrl (Cmd) + Shift and click on the sample point you made on the image you want to change (in Colin’s case, it’s the yellow dress). This will add a point on the curve and you’ll see the Input and Output values for both the source and the target colors. Now is the time to match them.

Look at the output values of the source image (the parrot fish, in this case). Copy them to the target image, and you’re almost there. You might need to tweak the L channel by pulling the point on the curve downwards.

Now the colors are matching, and all you need to do is bring the image back to RGB mode. Select the target image and the Curves adjustment layer and hit Ctrl (Cmd) + I to merge them. Otherwise, your adjustment layer will be lost when you go back to RGB. Now go to Image > Mode > RGB Color, and again, don’t flatten the image. And you’re good to go.

Personally, I’ve never worked in Lab mode so this seemed complicated at first. But as it turns out, you just need to follow the instructions and you can’t go wrong. : ) If you want to try doing it in RGB or CMYK Color mode, Colin writes that this method used to work perfectly. However, he points out that in newer versions of Photoshop you won’t always get the expected results if you use one of these modes. Still, I believe you could give it a shot.

[MATCH COLOR between images in PHOTOSHOP with CURVES and LAB | photoshopCAFE]