10 February 2010

Creating a sky gradient tutorial

The secret to getting realistic skies is to spend some time looking at sky photos to figure out what is really going on. I get to paint lots of skies with the work I do, so I have come up with a technique that seems to work and is easily repeatable. All skies require gradients, but the best way to do it is to put each color on its own layer. To do this, set your gradient to the foreground to transparent option. It's the gradient swatch just to the right of the top left one (foreground to background). This is the only gradient I use. In a moment, you'll see the control and flexibility this method will give you.

The next thing is to choose the right colors. First, always work in RGB mode, even if your image will end up being printed with the CMYK process. Photoshop works natively in RGB and some features don't work at all in CMYK. Getting consistent color is a tricky thing, going far beyond this simple tutorial. Just choosing colors at random from the Color Picker only adds to problem. What I do is choose colors from a Pantone library as much as I can. Click the Color Libraries button in the Color Picker. From here, you can choose the library you want. I use the Pantone solid coated library because it matches the PMS book I have. If I am working for print, I pick the PMS color based on the corresponding CMYK swatch in my book. This method may seem strange if you aren't working with spot colors, but it is a great way to keep consistent with your color and it gives you a nice range of dark to light to pick from. If your image will be printed, this method should give you less surprises with color.

Now the first thing to do is pick the major color of the sky. For this one, I chose PMS 646 and filled the bottom layer with it. A handy keyboard shortcut to fill with the foreground color is OPT+DEL(Mac) or ALT+Backspace(PC). To fill with the background color, do the same thing, except use CMD instead of OPT(Mac) or CTRL instead of ALT(PC). It's also a good idea to label each layer with the the color you used on it. That makes it easy to come back and make changes or pick the same color for something else. Then create a new layer above the solid color layer and use the gradient tool on it. Hold Shift while you drag up in order to get a perfectly vertical gradient. I chose 642, a lighter color from the same group as 646. Now, if it's not quite right, you have a lot of options. You could move the gradient on its own layer up or down, change its opacity, or even its blending mode. You could check the Lock transparent pixels option for that layer and fill it with an entirely new color. You can use as many gradient layers like this as you need to get just the right effect. For this sky, I used only three layers. Notice that I changed both the blending mode and opacity of the topmost layer. Skies always get lighter as they approach the horizon because you are looking through more atmosphere. That's why items in the distance look lighter and bluer. I often use a grey gradient on a layer in Screen mode on top of all the other sky gradients to simulate this effect near the horizon.

That's it! With this technique, you can create any sky you want, even sunsets, stormy, smoggy, and so on. A good practice is to get various sky photos and try to duplicate them. Add as many layers as you need. Use Multiply to darken and Screen to lighten. Next time, we'll tackle those clouds.

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