How-To: Use Spot Colors w/Photos

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Using Spot Colors With Photographs

Properly preparing photographs for spot color printing sometimes requires a little extra care and planning. The most common mistake when using photos in a spot color document is saving the photograph in RGB or CMYK color modes. This creates several problems; saving a photo in RGB or CMYK will always result in either poor photo quality, or the photo disappearing altogether, EVEN if the photo appears to be black and white. The proper way to save your photo for spot printing is in GRAYSCALE mode, regardless of what the final color will be. This can be done in Photoshop© by simply going to "Image -> Mode -> Grayscale".

There are several different ways to use photos in a spot color document, usually as a single colorized image or as a duotone. These also require a few extra steps in the design process.

SINGLE COLOR

The most common way to use photographs in spot color is by simply converting the image to a single color. In most cases, the photo is simply made black and white, which can be done easily by converting the photo to grayscale color mode (see above). However, if you are using another color other than black, you can also colorize the photo. To do this:

1. Convert the photograph to grayscale in Photoshop© as described above.
2. Place the photo in your final document layout in a program such as InDesign© or QuarkXpress©.
3. Using a direct-select tool (such as the white arrow in InDesign©), select the image, then select the spot color swatch you want to use.

EXAMPLE: You have set up a document in InDesign© that uses blue and red ink, and you want to put a photo in blue. You import the photo from your camera into Photoshop© and convert the image to grayscale mode. You place the photo in your InDesign© document, select it with the white arrow, and then select the "Blue" swatch to colorize the image blue.

DUOTONE

Duotones allow you to create deeper, rich images by layering black and another ink color on top of each other in the printing process. To create a duotone:

1. Convert the photograph to grayscale in Photoshop© as described above.
2. Go to "Image -> Mode -> Duotone". This pulls up your duotone options. Select the color ink you would like to use. NOTE: You MUST make sure the name of the color you select match the EXACT names of the spot color swatches in your final document. The name can be edited directly in the Duotone menu. Black should just be left as "Black".
3. After creating the duotone, go to "Image -> Mode -> Multichannel". This splits the color into two separate channels which will be necessary for color separations.
4. Convert the image back to grayscale as described earlier. You will notice that even though you are in grayscale mode, your image is still in color. If you open the channel palette, you should see two channels, one that says "Gray", which is your black ink, and the other should be the color you chose in the duotone menu.
5. Save your file as a Photoshop©(.psd) document and place it in your final layout. NOTE: Some versions of QuarkXPress© may not support importing native Photoshop© files. If you cannot import a .psd, you can also select "Photoshop© DCS 2.0" in the "Save As" menu. This will create .eps file that can be placed in most graphics programs.

EXAMPLE: You take a photo for the cover of your newsletter and want the image to stand out more than just a black and white photo. You open the image in Photoshop©, convert to grayscale, create the duotone, convert to multichannel mode and then back to grayscale. You place the final .psd file in your InDesign© document ready for color separations.

Remember, when using spot color printing, black counts as a color. So if you are printing a two color job with red and blue, adding black in a duotone image would be adding a third color. It is possible to print a duotone using any two colors, but black usually provides the sharpest image.