View Full Version : Color Casts....

Paul Pagano
03-17-2008, 06:02 PM
I wonder if some of the more seasoned photographers would chime in about color cast...

Since starting avian photography oh, about a year ago, I hear a lot of people mentioning a color cast in a critique as if it is something that must go. Aren't these casts created at the scene and by the scene? And if so, isn't it 'what' the photographer saw? (I've always had this issue with night shots that attempt to make the image looker brighter than it actually was...usually a long exposure will make the details viewable but not artificially lit...anyway...)

When a (sunset) light cast is present, no one seems to mind a white bird that looks orange...but it seems in any other instance, a color cast is not welcomed. If it was what the photog saw, why is this so? I don't seem to mind them but maybe I'm just not meant to critique.

Thanks in advance for your comments.

Charles Glatzer
03-26-2008, 08:19 PM

White Balance in digital cameras matches the color temp of the light with the capture medium. For all intensive purposes this means the color of the subject is supposed to be represented accurately w/o shift. Yes, Auto WB can alter sunset images by negating part of the warm cast. It is up to you to present the image as desired.

You can easily view and correct a global image Color Cast as follows;

Duplicate the background layer (Ctrl J), go to Filter > Blur > Average (the color seen is the cast present), invert the color (Ctrl I), set the layer blending mode to Color, and use layer opacity (approx 10-15%) to negate the cast.



Jim Poor
03-28-2008, 08:22 AM

Will this method alleviate the problems with using an action that creep up with using a levels adjustment layer and the gray dropper?

Alfred Forns
03-28-2008, 09:01 AM
Hi Paul I understand what you are saying and can see how it is confusing

When you have a bird in soft late afternoon light it does have a cast and I would not like to remove it It is the effect we are trying to achieve But you are correct it some sort of a cast A snow scene with no clouds often renders the snow with a bluish tint This is also a cast but not desirable In this case I would remove Not sure it it makes sense

It is a subjective thing !!!

Thanks for the color balance info Chas !!! Best way to do it !!!

Leroy Laverman
03-28-2008, 09:09 AM
Interesting Chas, I gave it a try with some images that I intentionally added a cast to to see the effects. Seems to desaturate the images quite a bit to neutralize a strong cast but works OK if it's a minor adjustment.

Paul - color casts are tricky. Especially since we are not all looking at the same monitor and inevitable differences will arise. Having "correct" white balance is not always desirable. You mentioned the nice warmth you get with sunrise/sunset light. You probably don't want to make the whites actually neutral white at that point. Many times it's simply a matter of preference. Some like cooler images others warmer - even bright in sunlight. As far as changing it goes, the best way I've found is in the raw conversion step. Play with the color temperature slider and to a lesser extent the tint adjustment. The color temperature adjusts how blue (lower K setting) or yellow (higher K setting). Tint will alter the green (negative settings) and magenta (positive settings). I've has some fun with night/sunset shots by drastically changing the tint to large positive values. The result was really deep purples. Here's an example where the only difference it the tint on the left was unchanged from the original setting (0 in this case) to +50 on the right.

Ian McHenry
03-28-2008, 04:01 PM
Hi Paul
As another newie to this image editing after going thro' the usual Artie editing sequence I will look at image to see if colours look right and if not will try to remove colour cast with either Remove color cast dropper or auto levels or auto smart fix.
If it looks right to you that's what I see as most important.

Paul Pagano
03-28-2008, 06:57 PM
Interesting thoughts everyone, and thanks. I think some casts add to an image and perhaps others do not. Like many have said, it is pretty much your image to present to the world...