Monday, November 14, 2011
Fix Dull Skies And Make Them Blue—11/14/11
Create beautiful blue skies, in the camera and the computer
|This Article Features Photo Zoom|
So how do you prevent a dull sky in the first place? You try to address the problem in the camera while you're shooting. You shoot on blue-sky days rather than hazy or overcast days. You pick a time toward sunrise or sunset, not the middle of the day. You choose an angle where you're not pointing your camera toward the sun, but rather away from it or at a 90-degree angle to it. You utilize a lens shade to prevent flare, which can rob you of contrast and saturation. And whenever possible, you strap a circular polarizer or neutral density filter to your lens and position it just right to deepen the blue sky. You can also underexpose the ambient exposure (making the sky a darker blue) and use fill flash to illuminate a foreground subject. Each one of these steps will help you capture a beautiful blue sky in the camera. Combine all of them and you'll practically ensure the prettiest deep blue sky you've ever seen.
Unfortunately, sometimes you just can't capture a blue sky in camera. You're at the perfect location at the exact wrong time of day, and your angle is toward the sun, and the sky is a bit too hazy. And you wind up with a dull white sky, maybe a vague pale blue at best. So you bring it into Photoshop and do your best to turn a dull sky into a beautiful deep blue? Here's how I do it, but be warned: In my opinion there's no substitute for capturing the perfect blue sky in camera.
First, I duplicate my image onto a new layer. Then I select the dull sky using the magic wand tool. I add to the selection by holding the shift key and clicking in new areas of the sky until almost all of it is selected.
There are two major problems with trying to replace a blue sky with an even bluer sky. One is making an accurate selection of the sky in the first place. I find that getting as close as possible with the magic wand is a good start, but the real secret weapon comes by way of the Refine Selection tool. Open the Refine Selection tool via the Select menu and, without adjusting any of the options in the dialogue box, paint along the edge of the selection area. The tool will examine the area in which you paint and, just as the name suggests, refine your selection more precisely.
This is immensely helpful in separating any subject from the background sky, and absolutely invaluable if you're trying to replace a blue sky around trees or foliage. The edge of a tree is, quite obviously, very intricately detailed, and without a highly refined edge this will be the first place where you'll give away your secrets. The second place is the tiny gaps of sky that almost always occur within trees and foliage. For these, I select the magic wand tool again, and this time uncheck the "contiguous" box. This way when I select a bit of sky, all the areas of similar color and tonality in the image will also be selected. (You'll likely then have to deselect other random areas throughout the scene, but the lasso tool is perfect for this.) It's a great way to select all those tiny little gaps in the foliage that would otherwise give away the fact that you've replaced the blue sky. With another round of the refine edge tool, you'll again have a wonderfully precise selection, this time containing all of the sky in the scene. Save the selection in the Select menu, because you'll be back for it in a minute.
Next it's time to determine what type of sky you'll use to replace your dull sky. This is the second major challenge to successfully replacing a dull sky—trying to do too much. If you replace a dull gray sky from a dull gray day with a bright blue sky from a bright blue day...well, no matter how well you do it, it won't look right. Gray days reflect flat, gray light on foreground subjects. Blue sky days reflect bright, colorful, contrasty light. Mix the two and the scene will scream "fake." So the key is not to do too much, not to go too far. If you think of a sky as a scale from 1 to 10, with one being the worst gray sky and 10 being the most beautiful blue sky, don't replace a 2 with an 8. Replace a 2 with a 4, maybe even a 4. Replace a 7 with an 8, or possibly a nine, and so on. Don't try to do too much or it won't look real.
Back to our scene. I like to replace a blah sky with a blue sky from another image I have on file, preferably one that's shot at a similar perspective. (Even though the sky seems so large and empty, differences in perspective are visible.)
Instead of finding a matching donor sky, another approach is to adjust the levels and saturation in the existing sky. This is only effective with already decent skies that you're trying to make more bold and dramatic. If you try to get a light white or gray sky deep blue, you can't do it with levels and saturation. You'll have to find another file from which to source your sky.
New sky in hand, simply copy it and paste it into the original photo on a new layer. With the previously saved selection active, choose Paste Special from the Edit menu, then Paste Into. The sky will be masked appropriately according to the selection you've made, and pasted onto a new layer. (If the pasted sky isn't quite large enough to completely cover the dull sky, you can use the Transform tool to scale up the blue sky to fit. If it's way too small, you'll have to start with a larger source sky in the first place.) At this point you will see immediately just how precise your selection is, and just how successful this replacement might be. Chances are, though, it doesn't look great. At least not yet.
The odds are good that you've still got some elements of old pale sky showing through, especially around the edges. This is where the last refinements come in to help mask the fact that the sky has been replaced. And for these, I like to use the clone stamp.
I duplicate and merge the top two layers, sky and scene, into a brand new layer onto which I can work. I then use the clone stamp set to "Darken only" to cover the strips of white sky showing through at the edges.
In the end, if the sky is still too dark and unreal, use the brightness and levels controls to lighten up the blue sky. I know it sounds counter-intuitive to lighten up a beautiful dark blue sky, but it can still be a considerable improvement on the original dull sky. To work, though, it can't be over the top and unrealistic.
Lastly, and this is the part that most photographers ignore, you'll probably have to make some adjustments to the non-sky areas of your finished image. Why? Because a bright blue sky brings with it certain things—like the higher contrast and more intensely saturated colors than an overcast or hazy day. So if you want to up the believability, you'll have to tweak the rest of the image, not just the sky.
In the end, no matter how well you do, on some tricky images it can be next to impossible to convincingly replace a drab sky with a blue one. In these instances, it's best to go for subtlety, and if at all possible, return to the location to photograph it under more forgiving circumstances. Because as is so often the case, it looks best if you actually get it in the camera.