How to extract and replace white balance tags?

[et2511299562]

I'd like to extract all of the white balance metadata from one raw file, and overwrite the white balance metadata for a number of other files.

What happened was I took a reference white balance card picture, but then I didn't set my camera to use the custom white balance correctly. So I want to batch process a bunch of pictures to incorporate the correct white balance information.

Since I still have the reference white balance card picture I took, I figure that I can go back and correctly configure my camera to use that picture, then snap a few more pictures so that have new images with the white balance metadata set correctly. Then I can use those new images as a reference point from which to extract the white balance metadata.

The question is, how do I go about doing this, in general? How do I know which data I need?

I have a Canon 600D, if that matters.

Thanks in advance.

[Phil Harvey]

I don't think that this is something I would recommend trying for a couple of reasons:

1) It may take a lot of trial and error to determine the tags you need to change, and the required tags may be different for different software (there is much redundant white balance information in many RAW images).

2) The embedded preview images will still have incorrect white balance.

I would instead recommend batch processing these images to convert them to JPEG or TIFF using the correct white balance.

- Phil

[BogdanH]

I agree with Phil... and if I may add (to clarify):
If you took at least one raw shot with grey card, then in Canon DPP, you can simply copy "recipe" from that image and apply it on all other images -that's the proper way to correct white balance. Or is there something I didn't understood in your question?

Bogdan

[et2511299562]

If you took at least one raw shot with grey card, then in Canon DPP, you can simply copy "recipe" from that image and apply it on all other images -that's the proper way to correct white balance. Or is there something I didn't understood in your question?

Hi, thanks for the quick replies.

Actually, this is precisely what I tried to do, but for some reason, DPP kept crashing on me. (I checked, and I have the latest version.)

Also, though, I was just curious as to how I would go about doing what I wanted to do. I didn't know if there was a well-defined set of tags that would do the trick, so I figured I would ask.

If there's a way to do this, I'd still love to know, even with all of the caveats.

[Phil Harvey]

If there's a way to do this, I'd still love to know, even with all of the caveats.

The command could look something like this:

exiftool -tagsfromfile src.cr2 -Canon:WhiteBalance -WB_RGGBLevelsAsShot -WB_RGGBLevelsAuto -WB_RGGBLevelsMeasured dst.cr2

But again, I don't recommend this and you'd have to do more testing to see what tags you needed to copy (if you can get it to work at all with the image processing software that you use).

- Phil