Lightning Brain has offered up yet another InDesign plugin to make your life easier. This time it's Color2Gray, which allows you to convert placed color photos in your InDesign document to grayscale without modifying the original color image via Photoshop.

Sometimes you want a particular picture to be output as a grayscale image, yet the original image is in color. You could open the image in Photoshop and convert it to grayscale, but you can instead use this InDesign plug-in to do the work for you.

Keep in mind two important things – when outputting in CMYK, the gray image will only render on the black (K) plate, and the original image is NOT altered in any way.