To quickly correct a slight dominant, or a lack of contrast, use levels, to control the values of each color.


1. Levels automatic


image obtained with the "automatic levels" You can leave the odinateur manage color values of your image, using the Image> Settings> Levels automatic.
 
This manipulation may be successful but, according to photos, not to be satisfactory. If so, try operations below.
 
(note in passing that there also commands "Colors automatic" and "automatic contrast", which also make corrections colorimetric calculated by the computer)
 



2. Levels

We are seeking a better contrast and forcing slightly red, we are going to operate manually, with the Levels tool.


The histogram reds To access the window "Level", open the menu Image> Settings> Levels or type Ctrl + L.
 
The bar that appears is the breakdown in the image of light and dark tones. On the left, on a dark tones and right, clear tones.
A histogram whose bars are much higher than left to right, for example, mean that the image contains too many dark tones.
 
There is a histogram for each color that make up the image.
 



3. Manipulating levels


Moving sliders The bar must begin at the beginning of its frame and end to end. This means it occupies the entire spectrum of values, with blacks and whites.
If this is not the case, move the cursor to the first bars.
 
For most images, it is preferable that the masses of the histogram are not all left or all right, if this is the case, move the cursor gray middle.
 
The histograms of each color can be very useful.
Handle them individually if your dominant is colored (see below, the dominant yellow) and check them in the same manner as the histogram.
 
For this image, we increased the contrast in bringing the sliders of the histogram, then forced midtones red by moving the cursor through the red bar to the left.
  



Another example is the dominant yellow

The dominant yellow is a classic of the photo, it is the result of a shooting indoors with artificial light, without flash.

The correction is different depending on how color image; CMYK (Cyan, Magenta, Yellow, Black) or RGB (red, green, blue).
This is because one uses subtractive color (CMYK, created for printing paper) and the other additive synthesis (RGB, for the screen).
Here, it corrects the same image in 2 versions: one in CMYK and the other in RGB.


   CMYK mode, in the histogram yellow, you have to push the cursor much to the left.
 
  RGB mode, do the same in the histogram blue.
 




For a more detailed color correction, will be used preferably curves (ctrl + M or image> settings> curves), which can handle the full range of values for each color.