Using the Channel Mixer to Correct Green Water

Hello James,

your article about color correcting green water gives a good introduction, but I would like to add something. The actuall work to remove the greenish water is does the hue/saturation tool. If you select

the cyan channel and add +20 you get almost the same blue in the background but preserve the colors and the saturation in the foreground.

The attached image is your first image manipulated with the settings mentioned above.

/ciao Lars

Thanks for the feedback Lars. I use the channel mixer because it's easier for me to interpret - vector based.

Although your shot w/ the Hue adjustment does look good, I still like mine better (big surprise eh?) :-)

Cheers

James

Your article about color correcting green water gives a good introduction, but I would like to add something. The actuall work to remove the greenish water is does the hue/saturation tool. If you select the cyan channel and add +20 you get almost the same blue in the background but preserve the colors and the saturation in the foreground.

Lars,

I think there are some situations where the modifying the channels is the only way to correct color problems. One typical case is where there is already a heavy cyan/blue cast on white or light-colored objects which were beyond the range of strobe illumination. Simply adding more cyan across the image is unlikely to help.

The channel Mixer is a convenient tool to play with channels, but Apply Image can be even more powerful, as you can select any of the standard blending modes, including selective modes such as darken and lighten.

The hue/saturation tools applies selective tint and does not in any way replace the channel mixer for certain types of problems. If you have good color balance but wish your water was bluer, then the hue/saturation tools works. In James's example, the entire image had a cast. The channel mixer is precisely the tool to address that.

There is a limit to how far you go with the hue adjustment as well. I use it all the time, but this is really a different problem. A global image problem needs a global adjustment, not a selective one.

The selective colour tool is also very useful for isolating casts in addition to those two options.

The hue/saturation tools applies selective tint and does not in any way replace the channel mixer for certain types of problems.  If you have good color balance but wish your water was bluer, then the hue/saturation tools works.  In James's example, the entire image had a cast.  The channel mixer is precisely the tool to address that.

I totally agree, that the hue/saturation tool isn't the only think to modify the colors of an image. I just wanted to show that it is possible to adjust the background water without touching other colors in the forground. You can even use this tool to remove all other colors except the one you want in the picture. This result is a b/w picture with some colored spots.

/lars