Photoshop: Monochromatic Image with Spot Color(s)

In recent years black and white photos with spot colors have become all the rage. A couple of years ago my sister-in-law decided to do a black and white of her son with a red sweater as a Christmas card. Problem was the red sweater was so vibrantly red that it drew your eye and distracted you from the rest of the picture. I have seen these types of pictures done well by professional photographers and not so well by department stores and at home Photoshop users.

The key to making these pictures work is the tonal values of the colors you choose. If you use a black and white background for your color and then drop in fire engine red you will be creating the same sort of image my sister-in-law ended up with. A red sweater and then the realization after the initial shock that there is more to the picture than the sweater, however, if you use a subtle red hue which takes cues from the black and white layer for shading purposes you will get something that melds together and highlights your picture.

Another key here is to not be married to black and white as the background. Depending on the color you want to be the accent you can choose a background color that blends more readily. For example, pink is the accent color, rather than use the start black and white background which may create a more fifties diner look you may choose to go with a deep brown maybe bending more toward the reddish side of the color chart. You can work with sepia as well.

The key to this technique is the art history brush.

1. In the history palette, change the left column where it shows the layer type choose it as the source for the history brush tool by clicking in the box. The icon will change to a brush with a swirl behind it. When you scroll over it the caption "the source for the history brush will pop up. [Figure 1]

2. Change the image to black and white mode. {Image - mode - gray scale} [Figure 2]

3. Change the image back to color mode. In order for the history brush to work you must change back to the original color profile. If you started with a CMYK image you will change back to CMYK. If you need an RGB image you will have to change at the end of the process.
4. Choose the art history brush tool from the tools palette. Be sure to adjust the flow and opacity to get the desired effect. 100% (left side of image) will produce the dramatic image and 60% (right side) will give you a subtler look. [Figure 3,3b, 3c] Be sure to adjust your brush size according to the portion of the image you are re-coloring. Any slip outside of your image will add color to the surrounding area. You will have to undo {control z} your last stroke and begin again. 

5. Another option is to color the background instead of the flower. [Figure 4] 

6. Yet another option is to choose the art history brush instead of the history brush tool. You can then choose different brush styles to work with as well as your opacity and flow. This will give your original image a more artistic, brush stroked appearance. [Figure 5]