If it is difficult to understand if an image is too red (or too little) or too green, it is even harder to understand if there are too red (or green or blue) only in the shadows of an image, or only in the bright part or in the middle. Only by trying you can feel the need to increase or decrease a particular color in the shadows (or bright or in the middle). For this reason, the node rig we are talking about this time,  is particularly convenient, Because it allows you to view and compare in a single screen many options.

actually this time is not useful append nodes from this file, for several reasons.
first of all the nodes used are very simple  (individual nodes “rgbcurve”).
Then, it is likely that adjustments should involve as many colors and not just one of the  three primary.
Finally, for this kind of adjustment is much more effective the node “Color Balance” ( we see  when we examine the color grading). The reason why I have not used “color balance”  is that I wanted to act in a way that the regolation is immediately obvious in the light spectrum chosen.
I say well, the node “color balance” acting on the values of light and shadow in a very gradient way, as a smooth curve.

The node that I used  act only in the choice without affecting other parts of the light.

so I can understand unmistakably if I have to change only shadows or the highlights and what color.

attention

In recent versions of blender have been some changes that have made it almost unusable this file.

It works well up to version 2.61 (download here).
Soon will upload the version will working  with the latest release.

http://www.luceri.it/wp-content/plugins/downloads-manager/img/icons/default.gif download: color balance.zip (118.80KB)
added: 26/11/2010
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Next time we’ll talk about color mapping

A complete and extended version of these articles will be published

in the next BLENDER ITALIAN MAGAZINE