Download P2B Perfect Skies

1. Added "P2B Grey Sky to Subtle Blue" action. See the samples below.
2. Added a few more usage tips to this doc.
3. Added ActionDex information.

Prompted by more than my fair share of photos with blown out skies plus a posting on the dpreview.com forums showing a clever quick fix technique for correcting skies using Filter>Render>Clouds, I decided to explore the possibilities for generating realistic looking replacement skies.

You might ask why not just use a sky from another picture? I certainly do that as well but sometimes this approach is just quicker, it generates a different sky every time, and the skies do not overpower the rest of the picture (obviously the sky was not the main subject of such pictures or it would not be blown out ;-). You even have some control over where the virtual sun is if you really want to make the sky look authentic for a given picture. The effect is also useful in combination with some photo-art actions. Some examples follow (none are great pictures, just what I used while developing the action):

The original:

After running Perfect Skies using the default "normal" clouds:

After running Perfect Skies using "vivid" clouds (after the cloud generation step, stop the action and hit ctrl-alt-f, then continue the action):

With a few post action adjustments, you can make decent overcast skies as well:

The horizon line can be adjust to control the amount of perspective (note how the clouds are bunched up closer together the lower they are in the sky). I also created a small gradient layer mask at the bottom of this image on the Clouds 1 & 2 layers. The original for this shot appears a bit further down this page.

Before and after of using "P2B Grey Sky to Subtle Blue". This is a very simple action that uses selective color to change dingy grey skies into a very subtle blue. The emphasis is not on trying to make it look like a nice sunny day but rather on not making the grey sky overpower the image. I find I use this action a fair amount because it just takes a second to run, has no user interaction, and the effect can easily be tweaked with the opacity slider after it is run.

Some additional tips on using P2B Perfect Skies:

• Doing a good selection of the sky is obviously key to this working well. There are a number of techniques for this. Select>Color Range often works well on blown out skies. After selecting, expanding the selection by 1 or 2 pixels will sometimes eliminate "halos" of old sky showing through around the selection edges. After the action is run, you can also edit the layer mask to adjust where the sky shows through.
• Duplicate the Clouds 2 layer, unlink it from the underlying layer, and then move it to create multiple cloud layers.
• Create a gradient fill layer over the Sky Fill layer to have more control over the background sky color.
• Create a gradient layer mask on the Clouds 1 and/or 2 layers (with black at the bottom).
• When using "vivid clouds", you often have to slightly decrease the lighting effects vector length or intensity (I find around 25-30 works well) to prevent blowing out the clouds.
• Interesting overcast skies can be made by decreasing the saturation in the Sky Fill layer.
• If you change the Style field in the lightning effects dialog, be sure to set the texture channel to "Cloud Alpha"
• Style "Soft Omni" is good for simulating the sun brightning an area of the clouds and then fading towards the horizon (works well with a desaturated sky fill layer).
• Using an emboss filter just before transforming can add depth.
• You can generate "just sky" pictures by starting with a new image, doing ctrl-a, and then starting the action at the Duplicate Selection step (click continue at the error about no background).