I usually do not have a problem with color cast in my photo's. Seems like lately when shooting around with alot of green (plants, trees and such)while out in the woods, I get a greenish tint in my photo's, causing shin tone to be off and sometimes the over all picture?
Is not using spot metering properly the problem?
Any insite and tips would be great. I do use a Canon 40D for now.
Light reflected from colored surfaces will affect to color of peoples faces and other objects. You may be able to correct for this using auto white balance, by adjusting the white balance during RAW conversion, or by adjusting for it in your image editor.
One way to correct color cast in PhotoShop is to use the highlights eyedropper tool in Levels. Click it on something in the image that should be pure white and it will adjust the RGB values to 255,255,255, or whatever preset you assign to it. You can set the presets by double clicking the eyedropper tool in the dialog box.
Posted by David Bostedo on August 15, 2010 at 8:17 PM
If you're shooting RAW, of course, you can possibly correct for some things by being able to set the white balance after the fact.
If there truly is an overall color cast (even if only in parts of the image), I like this method in PS :
-- Copy the flattened image to a new layer.
-- Select Filter->Blur->Average. You'll get a solid color image relating to the cast.
-- Create a levels adjustment layer and select the grey point eye dropper.
-- Click anywhere in the solid color.
-- Turn off or delete the solid color layer, and adjust the opacity to taste. You can paint or otherwise modify the levels mask to control which areas are affected.
We're sincere fans of custom white balances for matching skin tones in people. Whether or not you can see it, the subjects will spot the smallest variance, and your eye (or any post processing) stands a good chance of missing it.
Posted by Jim DeWitt on August 15, 2010 at 11:28 PM
One other thought. When I shoot with my Olympus E-500 at very cold temperatures, something goes wrong after all a while and all my shots acquire a distinct (and seasonally inappropriate) greenish cast. I've found the easiest way to correct the problem, after the camera comes back up to room temperature, is a hard reset using the built-in reset feature. Might work for you...
-- Copy the flattened image to a new layer.
-- Select Filter->Blur->Average. You'll get a solid color image relating to the cast.
-- Create a levels adjustment layer and select the grey point eye dropper.
-- Click anywhere in the solid color.
-- Turn off or delete the solid color layer, and adjust the opacity to taste. You can paint or otherwise modify the levels mask to control which areas are affected.
David, I tried this procedure, and it works a treat! However, I am curious about the following two items, though...
...and adjust the opacity to taste.
Which layer would I adjust? If the 'Average" layer is turned off/deleted, there is, of course, is no way to do this.
[i]You can paint or otherwise modify the levels mask to control which areas are affected.[i]
With only a Background layer, and a Curves layer, are you saying to create a Levels layer and adjust that (on RGB channel only), or are you talking about adjusting the Curves layer (RGB channel only)?
I'm a little confused. Would you please clarify for an old guy?
Preston,
layer>filter>blur>average
layer>curve or level> mid tone eyedropper average layer.
delete average layer - leave curve or level layer in place. Adjust opacity on that curve or level layer.
Flatten when finished adjusting
Posted by David Bostedo on August 16, 2010 at 5:21 PM
Paul has it right - I meant the opacity of the curve or level adjustment layer. And you get a layer mask with the curve or level adjustment layer (at least in CS4 I think you do) if you want to mask out certain areas from seeing the adjustment.
Thanks for all of your input. I take it that this color cast cannot be controlled while out in the field? Unless when you use AWB???
I did learn a fwe more things about CS4 you all are a wealth of information, thanks guys!!!
Posted by David Bostedo on August 16, 2010 at 9:15 PM
Auto white balance will pick what it picks and is often very good. If you're having trouble with it in the field, there are a couple of ways to get a "better" white balance :
-- Keep something that's a neutral (coffee filter, paper towel, etc) with you, and shoot a custom white balance in your camera. If the light is very constant, this works well; Otherwise you can update it every so often. This works for JPG and RAW, although RAW lets you change it after the fact.
-- Place a neutral grey object - like a WhiBal card in a couple of shots to give you a reference to set white balance by when working on the image. This works best for RAW, but may work OK with JPGs using the levels or curves tools.
I say "better" because sometimes you don't want neutrals to actually look neutral in the image if it's truer to what you'd see in real life. (Shady areas looking blue, for instance.)
Thanks, for the last post, you just reminded me that I have a neutral gray card in one of my other bags. It is rare that I had a color cast problem and that was one of the things I forgot about on how to compensate.
Setting the card in some of my shots would be easy to remove once the adjustments are made in CS4, I could clone the card out or crop it out!!!!
With the card in the shot, would metering on the card itself help also??
"With the card in the shot, would metering on the card itself help also?? "
The card must be oriented properly with respect to the direction of the light and camera position. If you go to Kodak's web site, you should be able to find the angle at which to place the card. I believe it is 45 degrees.
The reason for this is that if there is any glare from the card, it will cause an erroneous reading of neutral grey. This will result in a inaccurate exposure. Also, you would need to use 'spot mode' to read the card accurately. Additionally, if there is glare on the card, and you use the card for WB, the color of the card may be other than neutral grey; it could have a color cast that would affect your WB.
If you plan to use a grey card, I suggest you run some tests in varied lighting conditions to get a feel for how it works.
--P
Posted by David Bostedo on August 17, 2010 at 3:00 PM
Setting the card in some of my shots would be easy to remove once the adjustments are made in CS4, I could clone the card out or crop it out!!!!
And if the lighting is consistent over time, you could just take a test shot or two with the card, find out what white balance to set based on those, and apply that white balance to all of your shots. No cloning needed in that case.
-- Copy the flattened image to a new layer.
-- Select Filter->Blur->Average. You'll get a solid color image relating to the cast.
-- Create a levels adjustment layer and select the grey point eye dropper.
-- Click anywhere in the solid color.
-- Turn off or delete the solid color layer, and adjust the opacity to taste. You can paint or otherwise modify the levels mask to control which areas are affected.
I would like to add a note regarding this procedure. After you set the grey point and delete (or turn off the 'blur' layer) you may need to fine tune adjusment to get the color balance the way want it. To do this, adjust the levels in each of the RGB channels seperately. Remember that small changes in the seperate channels will have a noticeable effect, so a gentle hand is called for.
Once you have finished fine tuning, you can leave the this layer or flatten the image and then proceed with other adjustments.
Discussion
15 repliesIs not using spot metering properly the problem?
Any insite and tips would be great. I do use a Canon 40D for now.
Thanks,
Dave
One way to correct color cast in PhotoShop is to use the highlights eyedropper tool in Levels. Click it on something in the image that should be pure white and it will adjust the RGB values to 255,255,255, or whatever preset you assign to it. You can set the presets by double clicking the eyedropper tool in the dialog box.
If there truly is an overall color cast (even if only in parts of the image), I like this method in PS :
-- Copy the flattened image to a new layer.
-- Select Filter->Blur->Average. You'll get a solid color image relating to the cast.
-- Create a levels adjustment layer and select the grey point eye dropper.
-- Click anywhere in the solid color.
-- Turn off or delete the solid color layer, and adjust the opacity to taste. You can paint or otherwise modify the levels mask to control which areas are affected.
-- Select Filter->Blur->Average. You'll get a solid color image relating to the cast.
-- Create a levels adjustment layer and select the grey point eye dropper.
-- Click anywhere in the solid color.
-- Turn off or delete the solid color layer, and adjust the opacity to taste. You can paint or otherwise modify the levels mask to control which areas are affected.
David, I tried this procedure, and it works a treat! However, I am curious about the following two items, though...
...and adjust the opacity to taste.
Which layer would I adjust? If the 'Average" layer is turned off/deleted, there is, of course, is no way to do this.
[i]You can paint or otherwise modify the levels mask to control which areas are affected.[i]
With only a Background layer, and a Curves layer, are you saying to create a Levels layer and adjust that (on RGB channel only), or are you talking about adjusting the Curves layer (RGB channel only)?
I'm a little confused. Would you please clarify for an old guy?
Many thanks,
--P
layer>filter>blur>average
layer>curve or level> mid tone eyedropper average layer.
delete average layer - leave curve or level layer in place. Adjust opacity on that curve or level layer.
Flatten when finished adjusting
--P
I did learn a fwe more things about CS4 you all are a wealth of information, thanks guys!!!
-- Keep something that's a neutral (coffee filter, paper towel, etc) with you, and shoot a custom white balance in your camera. If the light is very constant, this works well; Otherwise you can update it every so often. This works for JPG and RAW, although RAW lets you change it after the fact.
-- Place a neutral grey object - like a WhiBal card in a couple of shots to give you a reference to set white balance by when working on the image. This works best for RAW, but may work OK with JPGs using the levels or curves tools.
I say "better" because sometimes you don't want neutrals to actually look neutral in the image if it's truer to what you'd see in real life. (Shady areas looking blue, for instance.)
Setting the card in some of my shots would be easy to remove once the adjustments are made in CS4, I could clone the card out or crop it out!!!!
With the card in the shot, would metering on the card itself help also??
Again, information well taken, thanks again!!!
The card must be oriented properly with respect to the direction of the light and camera position. If you go to Kodak's web site, you should be able to find the angle at which to place the card. I believe it is 45 degrees.
The reason for this is that if there is any glare from the card, it will cause an erroneous reading of neutral grey. This will result in a inaccurate exposure. Also, you would need to use 'spot mode' to read the card accurately. Additionally, if there is glare on the card, and you use the card for WB, the color of the card may be other than neutral grey; it could have a color cast that would affect your WB.
If you plan to use a grey card, I suggest you run some tests in varied lighting conditions to get a feel for how it works.
--P
And if the lighting is consistent over time, you could just take a test shot or two with the card, find out what white balance to set based on those, and apply that white balance to all of your shots. No cloning needed in that case.
Dave
-- Select Filter->Blur->Average. You'll get a solid color image relating to the cast.
-- Create a levels adjustment layer and select the grey point eye dropper.
-- Click anywhere in the solid color.
-- Turn off or delete the solid color layer, and adjust the opacity to taste. You can paint or otherwise modify the levels mask to control which areas are affected.
I would like to add a note regarding this procedure. After you set the grey point and delete (or turn off the 'blur' layer) you may need to fine tune adjusment to get the color balance the way want it. To do this, adjust the levels in each of the RGB channels seperately. Remember that small changes in the seperate channels will have a noticeable effect, so a gentle hand is called for.
Once you have finished fine tuning, you can leave the this layer or flatten the image and then proceed with other adjustments.
--P.