Come fare a migliorare le fotografie dove è presente un cielo azzurro, magari un po’ spento?
Ecco un articolo interessante che spiega come creare un filtro in Photoshop che fa proprio al caso:
http://www.dreamstime.com/photography-article-1

Ed eccone l’estratto più interessante:

If not even such a filter helps, you can create your own filter in PhotoShop, by following these steps:

1. Load the image you need to work on;
2. Create a new layer (position your working area on this layer);
3. Select form the toolbar - Gradient Tool;
4. Select from the toolbar - foreground color - white
5. Select from the toolbar - background color - a shade of blue that fits your image
6. Using the mouse cursor draw the direction and size of the color gradient
7. Select from the Layers working area the option Multiply;
8. Select the opacity of the layer which fits your image.