View Full Version : Help w/ color cast. inskip 07-24-2005, 04:51 PM There's a bit of a blue color cast (esp in the whites) in this image that I want to eliminate. I'm sure this is a simple task for many of you, however I haven't been too successful at it. First of all, I tried to correct the white balance in my RAW converter manually by selecting an area that should be white(that's how I understood the directions), but that made everything go very yellow. I also tried selecting shade (taken in the shade) for white balance and that too made it go very yellow. Selecting the white point in PS makes it turn yellow as well. Any advice for me on how to color correct this image would be very appreciated. Thanks. PatrickB 07-24-2005, 05:11 PM Is this what you want?
I used some spot of her shirt as a neutral and added some blue with color balance to adjust the skin tone sketchy.
Patrick inskip 07-24-2005, 05:26 PM Thanks Patrick. It definately toned down that blue color cast. It's a bit yellow, but not as bad as when I tried to do it...Where were you when you selected the neutral point? Levels? Curves? And you said you added blue??
I wouldn't expect that when blue is what we're trying to remove. Interesting. Much improved. PatrickB 07-24-2005, 05:35 PM No problem,
I did it with the neutral picker in the curves dialog box. I just thought it was a tad too yellow and therefore added some blue. It could also use some red maybe, just give it a try with the color balance sliders ;) inskip 07-24-2005, 06:17 PM not really satisfied w/ it. Got out my Scott Kelby book and selected my white and black points. Adjusted the curve to adj the midpoints. Added a bit of blue and a touch of red, but color still seems a bit strange..ugh. This color correction business is a pain. Seems I always have this problem shooting in the shade. Kraellin 07-24-2005, 06:46 PM it looks fine. good job :)
Craig I thought you did a good job Inskip. Just a thought that a girl this young might have equal amounts of yellow/magenta. I balanced her light cheek to about 33% each.
Cheers
Dave inskip 07-24-2005, 08:12 PM Thank you. Maybe I'm being overly critical of my work. She just looks kinda yellow to me. I feel like a big dummy, but what do you mean balanced her light cheek to 33%??? You're anything but a big dummy. If you measure the values of "her" right cheek, the percent of yellow is maybe 5 or 6% higher in yellow. Open your info palette. Click on the arrow to open up the palette options. The first set keep as Actual or RGB. The second set change to CMYK. Now when you open up your info palette for corrections, you can see numbers for both RGB and CMYK modes. When you run the eyedropper over her right cheek you'll see that the yellow values are a bit higher than magenta. Do your corrections to even them out. Post again if you don't understand but please don't do the dummy routine again.. we're all learning here.
Cheers
Dave Gary Richardson 07-25-2005, 01:36 AM Did a levels adj on each channel, before applying a Curves adj to the hilight on her collar, just below chin.
If you position a Sampler where you want to check, when you open your curves to the channel you want to adjust, Ctrl+click on the same spot to put a marker on your curves graph. That way you can perform a spot adjustment rather than a more general adj of all tones. inskip 07-25-2005, 02:09 AM You did that w/ the original (1st) image, right? You just adjusted the white point and no black point, correct?
WOW Gary, thats wonderful. I will try your technique tommow, but I've had it, been working on this ALL day in between everything else. Thus, my feeling like a big dummy comment, but, I've already been scolded by Dave on this :knockedou
I have plans for this picture beyond color correction. I've seen a technique that Vikki does where she puts a soft white glow around it. Anyway, I can't wait to move along...
Thanks again Gary Richardson 07-25-2005, 02:13 PM Hi Inskip,
On the levels adj I just put the markers to the ends of the histogram for each channel.
Then I lowered the output white pointer to about 245. (whites were a bit blown out by the adjustment).
Now I put an eyedropper on the highlit white on the collar under her chin.This gave a reading with too much blue.
So I added a Curves adj layer, opened the blue channel, and put the sampler on the spot I had the eyedropper on. Ctrl+click to put a marker on the graph, then lowered that point to even out numbers in each channel.(as seen in eyedropper window).
By adjusting just on this point, the yellowing of darker tones is minimised.
Hope this is clear, and helps you a little.
This is much more difficult to describe than to do.
Oops almost forgot, yes, I worked from the original. inskip 07-26-2005, 01:22 AM I can't figure out where I'm going wrong w/ this color cast. I managed to correct another image today w/ a blue color cast, but this one is killing me...I just can't seem to get away from it being too blue or yellow. If I hadn't seen Gary's, I'd think it was impossible. Anyway, I followed Gary's instructions:
1. Adjusted levels for each channel. When you do this are you supposed to make the global(RGB ch) adjustment as well? I didn't. And I lowered the output white to 245 In the GLOBAL RGB Ch.
2. I used the color sample tool to mark the highlight. I then went into Curves (blue ch)and Command(ctrl) clicked my highlight to get a marker on the graph. When I try lowering it she gets too yellow.
Gary's looks right on to me, her cheeks are rosy not jaundiced and blue color cast pretty much gone. Gary if you read this, what do you mean to even out numbers in each channel(as seen in eyedropper window). Eyedropper window? I was keeping an eye on the info pallet while checking the highlight point. I want my channels to get as close as possible, within a couple points. I also have an RGB #1 where I put my sampler, is this where I should be looking?
:dizzy: Gary Richardson 07-26-2005, 04:46 AM Hi Inskip,
First of all, generally speaking I don't adjust the Common (RGB), except in this case where I decreased the Output.
OK, the sample I selected should be white, and if that is the case, the R G and B values should be the same.
So I Alt click on the Eyedropper tool to get the sampler option. Place a sample point on the highlit white. This showed the blue value to be higher than those in R and G.
Opened Curves adj layer. Went to drop down, and selected B channel. Moved the selector for curves over the same point I already had the dropper on. Ctrl+clicked to put marker on graph. Now used down arrow to nudge this point down, till value of blue was equal to that of R and G in sampler window.
(Will try to post some Screen Shots). OK, did a quick re-work, for some reason, the levels adjustment left blue a little low this time, so had to bump it up a little, but essentially used same process. Note: Screen shot programme may not have kept colour fidelity, shown for illustration only. Stroker 07-26-2005, 09:54 AM Steve's Curves tutorial:
http://www.thegoldenmean.com/technique/curves1.html
In particular, page 3.
Basically what Gary is saying.
Don't forget that you can mask adjustment layers. One adjustment for area and mask it. Another adjustment for another area and mask it.
In some photos, I'm done regular desaturating to varying degrees as opposed to trying to get rid of colour cast. Might be something to try. | |