Correcting White Balance after the shot (or does the white balance setting affect the shot)

[bonny_rais]

Hi there,

 

I've shot several images with the white balance set to flash,

accidently. Now, although the images are shot in RAW, I do not seem

to be able to get the colours the way I seem to remember them,

even though I play with the WB settings in Capture One Pro.

 

Images shot were red leaves (it's autumn here in Australia) and some

green acorns, yet when I look at them I see the leaves a lot redder

than I remember (that's because of the Flash WB), but the acorns are

yellow. No matter what white balance setting I choose or colour temp

I set, the colours are not accurate. My monitor is sort of calibrated

and previous images of the same subject (shot with AWB) were accurate

in colour.

 

Since I shoot in RAW, I thought that the WB setting in the file

is only an indication, but the image itself is not affected until

the conversion, but is my assumption correct? Does the camera alter

the sensor input in any way in if the WB setting is not AWB?

 

Thanks for info

 

Bonny

[gary_ferguson1]

"I thought that the WB setting in the file is only an indication, but the image itself is not affected until the conversion, but is my assumption correct?"

 

Well if you're wrong then I'm wrong with you! Are you saying playing with Capture One WB produces no change, or just not the change you want?

[Greg M]

Shoot the same image two or three times with different white balance settings on your camera while in RAW mode, then download them and see if the color cast is different in the previews. That will tell you if your camera settings matter while in RAW. I've never thought about that myself since I usually run through all the options in Capture One after the fact to see what looks "best" for that picture- I just leave it set to Auto White Balance.

[ashtonsmith]

There is no change to the file. RAW is exactly that, raw dump of info from the chip to your

card with maybe a little compression. The only setting that affects a RAW capture is ISO.

The WB, tint, saturation, contrast, white point (exposure), black point (shadow), and

sharpen are all variable until they are converted from RAW.

 

Have you tried setting the WB to where it should be for the shot and then using the tint

adjustment to make the colors right. WB only sets the neutral grey for the shot. While

most of the time the rest of the colors fall in line, that doesn't always happen. Sometimes

it takes user interpritation of the RAW data to make a good color balanced photo.

 

Hope that helps,

Ash

[ashtonsmith]

Oh, to let you know Gary, the previews will be different, but they are just the setting that

the camera would have used if you were shooting jpeg when the picture was taken. They

can all be changed/updated without damage to the original file. Those settings are stored

as part of the Exif data.

[ashtonsmith]

I meant Greg, sorry.

[robert_lombardi]

I agree, the white balance setting will effect your JPEG but not the RAW. However, the preview in Photoshop CS will show the white balance based on the EXIF info. For example, if you change the WhiteBalance setting in Photoshop CS, the preview will reflect the change. Othere programs may behave differently. For example, I think the Canon FileViewer utility allows you to see JPEG previews. These previews will use the in camera whitebalance setting.

[bonny_rais]

To everybody out there,

 

Thanks for the answers. In particular Ashton has confirmed what I

thought to be the case - the RAW file is not modified until conversion time and the WB is applied then.

 

However, my problem is still there and I cannot get the correct

coolours I thought were in the image. White Balance, it seems is only

part of the picture. Changing the WB alone is not sufficient as it only changes the colour temp. There is also tone balance and colour

cast that need to be used to get the image closer to what it was

(at least in my memory). THe situation cannot be helped by the

fact that there is no definitive source of white/gray in the image

as it is all green/red tones.

 

Anyway, I will continue tweeking ...

 

Thanks again

 

Bonny

[jim_larson1]

I use C1.

 

I never use the WB presets, as the Kelvin and Tone adjustments will override. I usually use "auto" to see what the camera's best guess is, then try one or two custom presets to see if I like them better, and finally I just tweak till I get what I want.

[theoldmoose]

Color temp will only correct yellow/blue casts. You need to tweak the tint for red/green corrections. Of course, shooting a gray card, or at least having something neutral in one of your images is a big help. I hear Tamrac bags are about the right color/tone 8-).

 

In cases like this, I would try to use one of the presets in the C1 pulldown on the color balance tab. If you took the shots in open shade or on a cloudy day, you may get a closer balance to start from.

 

Then, if there is a cast (I've gotten green casts from reflections from green grass in open shade), you might even be able to dump it if it is mainly in the shadows by going to the levels control, selecting the offending channel, and moving the black point up slightly. This was very effective for me, to get rid of a green cast to people's faces I had shot in open shade, where the pavilion was surrounded by brightly lit green grass.

 

In fact, I've seen a description where someone color balanced a photo, by just going to each of the R,G,B channels in the levels control, and setting the white/black points appropriately. If you see a color 'sticking out' or retracted in the composite levels, you'll know which one(s) to tweak.