When you’re working in a full color document in Adobe InDesign, you may occasionally want to see how the image looks in grayscale rather than full color. Normally this would require you to convert the image to grayscale in your favorite image editor. But you can quickly get an idea of how it will look without even leaving InDesign. Here’s how you do it: (more…)
If you’ve ever had to convert a logo or piece of artwork in Adobe Illustrator CS3 from color to grayscale (or even Pantones to CMYK), you’ve undoubtedly seen the “gradients and patterns will not be converted” warning message. The auto-convert function in Illustrator CS3 doesn’t work on gradients. You could go through the trouble of adjusting the gradient manually, but if you have a lot of different gradients, that can be time-consuming. 
Instead, select all the objects containing gradients (or just hit Command + A to grab everything) and go to the menu bar and select Object>Expand and hit OK. Your gradient is now converted into many objects with different shades of solid colors, rather than a single object with a gradient, so they can easily be converted to grayscale. In most cases, just hitting OK will do the job just fine. But if you find the results not to your liking, you might try adjusting the number of objects created to simulate the gradient at the bottom of the Expand dialog box first. The more objects you create, the smoother the gradient will appear when converted to individual objects. Because you have expanded the gradient to multiple objects, going back and editing the gradient is a royal pain, so be sure to save a copy of the original before you expand it.
If you’ve upgraded to Illustrator CS4, rejoice! The ban on gradient conversions has been lifted. We can now convert the colors in gradients to color, grayscale, or RGB by going to the menubar and selecting Edit>Edit Colors and choosing the appropriate option.
Adding color to a grayscale image is a great effect that offers a lot of visual impact with little effort. Many digital cameras can actually do it automatically. But the results are often less than optimal. Lesa Snider at The Graphic Reporter wrote a brief tutorial a few years ago that illustrates this simple technique that creates a central point of interest in your image. The tutorial involves the use of layers and layer blending modes, as well as the brush tool. Once you master the effect doing it as described in the tutorial, you can move on to using Masks and Channels for more accurate results. One bit of advice though, less is more. In other words, pick and choose the areas of your image you want to draw attention to the most. Colorizing most of the image defeats the purpose of the effect entirely. In the sample image above, I probably would have left the hat, gloves and purse in grayscale, drawing more attention to the purse. But that’s just my opinion.
Press Shift+Command+U to remove all the color (Desaturate) and make your image grayscale while still in RGB mode.