First and foremost, be sure to select a photo with rich and saturated colors. Once you move the little yellow box over the color you wish to isolate, click on the AE-L AF-L (connected to the eye dropper at bottom of screen) once you have picked up the color and see it in one of the upper boxes, you can now adjust the tolerance using the up & down selector arrows, to increase or decrease the overall tolerance (1-7), rotate the command dial till the number alongside the box is highlighted to choose 1-7, a very broad range of similar colors that will be included. A narrow range would work opposite. You can now either select another color in the second or third box or Once done, OK/Save, you may be doing it right but if the color you are selecting isn't that rich or saturated, or wasn't adjusted properly..... you should see a basic B&W with just the selected color. Hope this was helpful. So much easier in PP/PS