Matching Colors In Photoshop Part 2: Curves Adjustment Layer
by Jesus Ramirez
posted on 01-31-2017
In part one of this tutorial we looked at matching the Pantone Color of The Year, Greenery, on to a coffee cup by using the Hue blending mode.
In this follow up tutorial, we will use and advanced method using use the Lab Color Mode and a Curves Adjustment layer to precisely match the Greenery color to a red couch.
You can follow along by downloading this image of a “Modern living-room” into your CC Library or your desktop. You can follow the same steps in the previous example to download this image.
Start by switching your working color mode to Lab. Go to Image > Mode > Lab. If you receive a warning about merging layers while converting the image, choose “Don’t Merge”.
Note: Several adjustment layers, filters, and tools will not be available in the Lab color mode. Remember to convert it back to RGB (or CMYK) once you have completed the color match.
Select the Greenery color by typing #84BD00 in the Foreground Color picker window.
Create a new layer (Layer > New > Layer…) and name it “Greenery Sample Color.”
Then use the Brush Tool (B) to paint a circle above the couch. We will use this circle to sample the green color for the color match.
Select the Eyedropper Tool (I) from the toolsbar. Then select 11 by 11 Average, under Sample size, in the options bar. This option will help you get a more accurate representation of the colors you select.
With the Eyedropper Tool selected, hold Shift, and click anywhere in the green circle to place a color sample represented a crosshair icon that reads “1”.
Then click on the color that you want to change, in this case, the red couch. Make sure that you click on an area that best represents the color you want to change. Don’t click on shadows or highlights. A good area to click is the center of the middle cushion. Photoshop will place a crosshair icon with a “2” next to it.
The color samples will display their numerical values in the Info panel (Window > Info).
The values under Color Sample #1 represent the Green color and the values under Color Sample #2 represent the red color. To apply the color match, we simply must change the values from Color Sample #2, to match the values of Color Sample #1.
The best and easiest way to do this is by using a Curves Adjustment Layer. But before you create the Curves Adjustment layer, we must first confine the adjustment to only the couch.
Select the Quick Selection Tool (W) from the tool bar, and click-and-drag on the couch to select it. If you accidentally select an area outside of the couch, hold Alt (Mac: Option) and click-and-drag to deselect. In many cases, you will need to refine the selection, but a rough selection will work for this image.
With the selection active, click on the new Adjustment Layer icon and select “Curves”.
The selection will be applied to the Curves adjustment layer as a layer mask, all adjustments will only affect the couch.
Before you start the color match, make sure that the Curves Adjustment Layer is on top of the layer stack.
Click on the Curves adjustment layer to select it. In Properties Panel, click on the Targeted Adjustment Tool icon to enable it. The icon is a pointing hand with an up and down arrow.
Move the cursor over any area of the image. You will see a circle moving up and down the curve as you move. This circle represents the precise point in the Curve of the color that you are hovering over.
Hover over Color Sample #2, the middle cushion, which is the color we want to change. Hold Ctrl Shift (Mac: Command Shift) and click to place a point on the curve on all three Lab channels.
Make sure that you hold the two modifier keys as you click, or you will only create a single point in the channel that you’re currently in.
In the Properties panel, select “Lightness” from the dropdown. The Curve will have a sample point near the center. This point was created with the Eyedropper Tool.
Click on the sample point to select it, and type the corresponding value of the green sample color, found in the Info panel.
The L value for the Greenery color is 70. Click on the Output box in the Properties panel, and type “70”.
Repeat this step with channels A and B. Type “-37” in the Output box for channel A, and “73” in the Output box for channel b.
When you change all three values you will see in the info panel that the values of the two channels match, and that the couch is green!
The only problem is that the highlights have a slight yellow tint. To fix that issue, we cause the A channel, which controls Green and Magenta.
Select the A channel from the dropdown, and drag the white point down. Which will add green to the highlights and remove the yellow tint.
Note: The L channel controls the Luminance of the image, the A channel the controls Green and Magenta, and the B channel controls Blue and Yellow.
If you place the green circle over the couch you will see that the colors are the same. Of course, the highlights and shadows will be different, but the target color will be identical.
After completing the color match, remember to change your color mode back to RGB (Go to Image > Mode > RGB). When converting from Lab to RGB you will not be able to keep adjustment layers. You must flatten your image into one layer to continue.
And there you have it, a couch perfectly matched to Greenery.
Products: Photoshop, Creative Cloud