Photoshop Tip: A Trick with Hue/Saturation

PHOTOSHOP TIP: A Trick with Hue/Saturation
by Michael Frye

The Hue/Saturation adjustment does just what it says -- adjusts hue and saturation. It allows you to change the overall image, or just one color. A great feature of Hue/Saturation is that you can precisely define what colors you want to adjust. This feature is tricky to use, but I'll show you a way to make it easier.

As in the last tip, I recommend using an adjustment layer. Instead of going to Image > Adjustments > Hue/Saturation, go to Layer > New Adjustment Layer > Hue/Saturation. Or click on the New Adjustment Layer icon at the bottom of the Layers Palette; it's that little circle
that's half black and half white:

The pop-down menu at the top of the Hue/Saturation dialog allows you to choose "Master," to adjust the overall image, or one of the six primary colors. In the red maple image above, I want to adjust the hue and saturation of the red leaves without affecting the rest of the image,
so I'll select "Reds" from the pop-down menu. Once you select one of the individual colors you'll notice some sliders at the bottom of the Hue/Saturation dialog that look like this:

These sliders show what colors are being affected. Colors between the two small vertical bars are 100 percent affected. Colors outside the vertical bars but inside the two little triangles are partially affected. The original position of these sliders is Photoshop's idea of what red is, but the actual colors you want to adjust may be quite different.

The first thing I'll do is click on one of the red leaves in the image; this centers the sliders on the color I just clicked on. Next I want to move the sliders so that the changes I make will affect the red leaves, but not the tan-colored sand in the lower-right corner, which also contains a lot of red. But how do I know when I've adjusted the sliders correctly?

Here's the trick: First, I make sure Preview is checked, then I drag the Hue adjustment all the way over to the right so that is reads +180 (or over to the left so that it reads -180):

This turns the reds into a wacked-out blue, but don't worry, this is temporary. What this shows me is what colors are being affected with the sliders in their current position. I can see that both the red leaves and the tan-colored sand have become blue, so I'll move the little sliders at the bottom until the sand returns to its normal color, but the red leaves still look wacky:

Now any further changes I make will affect only the red leaves. I can return the Hue adjustment to zero, then adjust the hue and saturation of the leaves to taste.

So that's it: to see what colors you're affecting in Hue/Saturation, radically change the hue. Just remember to change it back! Then again, I sort of liked that wacky blue color....!