Curves and Painting Highlights

Photoshop is a mind-blowingly powerful tool. That's actually an understatement.

Today's photographers are shooting images with the understanding that they are going to be altered - or even finished - in photoshop. Just like Ansel Adams and his ilk shot negatives with the understanding that they were going to make them more or less contrasty by adjusting how they were developed. The difference is that, back in those days, changing the contrast of an image with chemicals was hard and never a sure thing unless you really knew what you were doing. Guess what? With photoshop, the fact that you can do virtually anything doesn't make it any easier if you don't know how. With a tool as powerful as photoshop, a few simple techniques can take you a tremendous way - it's like the imaging equivalent of a power-saw: you can cut 20 times as much wood with a chainsaw if you know how to use just that one tool safely. Unlike a chainsaw, photoshop has an undo command, which is very reassuring.

In this walkthrough I am going to show you one of the most powerful tools in photoshop. Once you understand how it works you'll be kicking yourself and asking, "how did I ever live without that!?"

Curve Adjustment Layers

First, you pick an image to work on:

(RC. Unaltered except for cropping; no clean-up)

Now, I want to give it a bit more light down on her legs and feet, and maybe make a few popped-out highlights on her shoulders. Sitting there trying to do this with dodge and burn would result in visible changes on the dark background areas.

Making Adjustment Layers

With your layers menu raised, go to Layer -> New Adjustment Layer -> Curves

(create a curve adjustment layer)

Now, you've got a curve adjuster. What you want to do, is set the curve so that it gives you the kind of highlights you want in the places you want them - ignore, for a second, the damage that it's doing to the rest of your image.

(adjustment layer curves applied to image)

Now, look at the "Curves" layer in the layers menu. See the white panel next to the curves logo? That's the layer mask. In photoshop layer masks, an area that is white means the adjustment is applied 100%. If it's black, it means the adjustment is not applied at all.

In my example, you can see I've got some decent highlights along the backs of her calves, now. Her shoulders are blown out and look like crap because of the contrast curve, but that's only because I am applying the contrast curve to the entire image thanks to the fact that the mask is white.

Ready to Paint

Let's get ready to paint. Activate the curves layer and fill it with black. You can either just use Edit->Fill (black) or select the whole image and hit "delete" if the background color is black.

(curves effect turned off by black-fill in layer mask)

Now I'm ready to start painting!! There are any number of tools I could use at this point - a soft brush with white, or a selection that I feather.

Now, instead of being limited to changing brightness of the entire image, you can adjust specific parts for exactly the effect you like. The bad news is that all this power means you have infinite opportunity to fiddle and fix until your fingers bleed on your track-ball.

Use any of the image manipulation tools on the layer mask. If you make a mistake, just paint black back over the area and the effect will be turned off again. If you think you're going to want the effect over most of the image, don't bother filling the layer mask with black; just leave it white and paint black over the parts where you don't want the effect to happen. The "MAXIM Look" glamour photographers get that shiny plastic skin look by using a brush along the highlight-line of a leg, or arm, or wherever, and then apply a gaussian blur to the entire layer mask. I've seen that trick used with a brightness/contrast adjustment layer to accomplish what some call "digital light painting."

Remember: you can combine layer masks atop eachother, ad nauseam.

(using other tools to alter the adjustment layer)

Just for the sake of my example I decided to make her Tshirt and socks "pop" with a bit more contrast - so I added another adjustment layer of Brightness/Contrast with the contrast and brightness turned up a bit, then selected and feathered the shirt and white-filled that area of the selection mask. I painted on her shoes, too, with my magic +5 paintbrush of bright contrast.



I tried to keep my adjustments fairly subtle - but you don't have to. I'm quite pleased with the way that the gamma-curve layer brings out (apparent) muscular definition in her right calf and her left ankle. Popping the shoes out goes a ways toward balancing the composition and giving the image some depth.

One popular look in "fashion" photography is the slightly sickly-looking pale-greenish model with shiny-looking skin. A lot of that is done in-camera with lighting, but the waxy specular highlights are done using retouching techniques like this one.

Bellwether Farm , Morrisdale, Pennsylvania Jan 20, 2007