Duotone - The Basics
  Duotone - Advanced
  Direct from RGB
    - HSL
    - Colour Balance
    - Selective Color
    - Color Hue & Tone
  Using Masks
 5. Direct from RGB - Colour Balance

Colour Balance

The Colour Balance settings in Photo-Paint are normally used to correct minor colour imbalances in photographs that have been taken under non-ideal lighting conditions (too warm or too cool) or to correct colour imperfections associated with film types or digital camera CCD qualities.

My Canon Powershot A5 tends to take images that are too cool (bluish) when using the flash and too warm (yellowish) without it in low light situations. Thus I often resort to the Colour Balance controls to correct for this. However, the Colour Balance dialog box can also be used to make large scale colour changes to images.


New Image & Checkpoint.

Lets use a different image here.
I have chosen the 790010.wi image from the Photos/Eve_sky folder of PP8 disk 3.
A resampled version is available by clicking HERE or on the image.

   - Save a checkpoint so that you can return to the original later.

Open the Color Balance controls:

   - Image > Adjust > Color Balance.


The Color Balance Dialogue

The Color Balance controls allow the user to alter the balance between the extremes of the three RGB channels and their inverse CMY colours.

Adjustments can be made to luminance ranges of Shadows, Midtones and Highlights, either separately or in combination, and with or without the preservation of luminance values..


Experimentation - The Best Medicine.

The best way to discover how Color Balance can be used to alter image properties is through experimentation.

As an example, set to sliders to:

   - Cyan-Red:100,
   - Magenta-Green:0,
   - Yellow-Blue:-100
   - With Shadows, Midtones and Highlights ON
     but with Preserve luminance OFF.

If you have the instantaneous full screen preview mode set ON you will see the changes instantly without needing to press OK.

The image should appear as shown.


Some Examples

Below are some settings to try with the Color Balance controls and the results:

   - Click on the small images below to change the larger image

   CR 100;
MG -50;
YB -100;
  CR 100;
MG -50;
YB 100;
  CR -50;
MG 90;
YB -50;
  CR 100;
MG 0;
YB -100;
  CR -100;
MG -100;
YB 60;
S .

CR=Cyan-Red,   MG=Magenta-Green,   YB=Yellow-Blue,
S=Shadows On,  M=Midtones On,  H=Highlights On,  L=Preserve luminance On
(no letter for a luminance range means that the range is set to OFF )


The next section looks into the powerful colour change controls in the Selective Colour dialogue.


Copyright ©, 1999. David Mutch Ph.D. and Visionary Voyager Corporation.
All rights reserved.