Spot Color Replacement

Replace the color of an object but keep the underlining tone and texture

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On this web site, editing color falls into three categories: Color Correction, Color Balance and Color Replacement. 

Color Correction is the removal of unwanted color casts by neutralizing blacks, grays and/or whites.  Color correction is discussed on the Levels Color Correction page and the Curves Color Correction page.

Color Balance is the changing or enhancing of an image's color bias toward a primary or secondary color.  Adjusting color balance is discussed on the Color Balance page.

Color Replacement is the changing of hue and saturation.  There are several Photoshop features related to color replacement, such as the Match Color command, the Replace Color command and the Selective Color command.  In addition, the Hue/Saturation page describes how to use the Hue adjustment to change color.  However, this section of the web site describes a technique for selectively replacing an object's color without affecting its underlining tone and texture (detail).

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Selective Color Replacement

To see how this technique works, we will use an example consisting of three color rows.  This will allow us to see the affect of combining the color from one area with the tone and texture of another.

In Figure 1 are three horizontal rows.  The bottom row is a medium blue, the middle row is a medium green and the top row is a dark green.
 

Objective

The objective of this exercise is to make the middle and top rows match the bottom row.
 

Adjust the Middle Row

To change the middle row, the following steps were taken.

1. Create a new layer by clicking the Create a new layer icon at the bottom of the Layers panel.  Make sure the new layer is above the layer containing the middle row.  Name it something useful, such as Overlay Color.
2. Change the layer's blending mode to Color.  Make sure the layer being changed is the new layer created in step 1 and not the layer containing the middle row.
3. Activate the Brush tool and select an appropriately sized brush and edge.
4. Hold down the Alt (Option) key until the brush becomes an eyedropper.
5. Select the blue color from the bottom row.
6. Paint in the new layer so the middle row is covered with the blue color.

Figure 2 shows the result.  In this example, I painted only over the right half of the middle row in order to show the before and after effects.

Because we changed the new layer's blending mode to Color, Photoshop takes the tone and texture from the middle row and the hue and saturation of the new layer and blends them together for our result.
 

Adjust The Top Row

Now, lets repeat the steps above for the top row.

1. Create another new layer by clicking the Create a new layer icon at the bottom of the Layers panel.  Make sure the new layer is above the layer containing the top row.
2. Change the new layer's blending mode to Color.  Again, make sure the layer being changed is the newly created layer and not the layer containing the top row.
3. Assuming the Brush tool is still active and the blue color is still the Foreground color, paint in the new layer so the top row is covered with the blue color.

 

Figure 3 shows the result.  As we can see, the top row is blue.  However, it is a much darker blue. Why?  Because this technique blends the tone and texture from the original layer with the color of the new layer.  Looking at Figure 3 again, we can see the green of the top row is a dark green.  This means the tone of the top layer is dark.  Therefore, Photoshop took the dark tone of the original layer and blended it with the blue of the new layer which resulted in a dark blue.

Can this be corrected?  Yes.  But the answer is not in selecting a lighter blue to somehow offset the dark of the green.  We use the same blue, but we have to change the tone of the original dark green to match the tone of the bottom row.
 

Changing Tone

I do not go into changing tone here because managing tone is intensively covered in the Levels section and the Curves section.  However, as shown in Figure 4, I created a Curves adjustment layer above the layer containing the dark green and below the overlay color layer.  I then applied a layer mask so the adjustment would only affect a specific area and then adjusted the curve so that overall tone was lightened to match the medium blue.  I also changed the blending mode of the Curves adjustment layer to Luminosity to prevent the adjustment from changing anything other than tone.  The result can be seen in Figure 5.

In Figure 5, the top layer shows the original dark green, the resulting dark blue when only the color layer is applied and the medium blue when both the color layer and the Curves adjustment layer are applied.
 

Key Points

The key points of this technique are as follows.

• The layer containing the replacement color needs to be above the layer containing the object being changed.
• The blending mode of the layer containing the replacement color needs to be Color.
• If tone needs to be adjusted, the adjustment layer used to change the tone needs to be below the replacement color layer and above the object layer.
• The tone adjustment layer will more than likely require the use of a layer mask to isolate the area to be changed.