Correcting a fine-adjustment white-balance error


#1

Last weekend I discovered that at some point I had managed to set the fine adjustment on the white balance of my Canon 70D off by a small amount in the Magenta-Amber direction - not sure when I did it, but it probably explains why I was getting comments about the WB of my photos being slightly off.

Can anyone suggest which colour parameter(s) to tweak to fix photos taken while it was offset.


(Morgan Hardwood) #2

@jtappin well the white balance of course :slight_smile: But that answer is too simple, so I assume you omitted some info? Is it raw files you’re processing?


#3

I’d suggest you take two test shots, one with normal WB and one with the same incorrect WB setting, and figure out the setting needed to make the incorrect one match the correct one.


#4

Yes, raw files.
I thought that it might be a common enough issue that someone would know offhand which WB settings to tweak, before I started playing with settings and possibly making things worse. Since most of my digital photography is wildlife, there is a tendency to have either very blue (sky) or very green (hedgerows etc.) backgrounds which RT’s auto balance settings do not handle as well as the camera does.
Essentially the 70D (like other cameras that I’m familiar with) has a 2-D fine WB control with Green-Magenta and Blue-Amber axes, and the adjustment was off in the Magenta and Amber directions.


(Morgan Hardwood) #5

@jtappin play with the White Balance Temperature and Tint sliders in RawTherapee until the preview looks right, then copy and paste this setting to all other photos taken in the same light. If any photos captured a neutral-colored object, e.g. a not-clipped white piece of paper or white shirt or white car, you could take a white balance sample off of them. But in the end just choose something which looks good.

You could also take a sample from the dark part of a cloud if it’s daylight and the sun is not low in the sky, it often looks good. In this example I sampled the area marked with the Lab* color picker:


#6

Thanks, bringing the Tint about halfway back towards 1 (it was at about 0.7) showed a decent improvement.