Search found 51 matches
- 2010-02-15T07:59:19-07:00
- Forum: Users
- Topic: White Balance Correction Using a Grey-card Reference
- Replies: 36
- Views: 60344
Re: White Balance Correction Using a Grey-card Reference
No, I'm not thinking of blend; it's just a 'tracing-paper' method really.
- 2010-02-15T01:59:40-07:00
- Forum: Users
- Topic: White Balance Correction Using a Grey-card Reference
- Replies: 36
- Views: 60344
Re: White Balance Correction Using a Grey-card Reference
Hi, Fred? You're right about the 128x128; that was for the full size images. I also see what you mean about the overlay compositing method but I can't see a way to do without needing shifts in levels, which I was trying to avoid because of the possibility of clipping - I might've misunderstood the n...
- 2010-02-14T06:24:57-07:00
- Forum: Users
- Topic: White Balance Correction Using a Grey-card Reference
- Replies: 36
- Views: 60344
Re: White Balance Correction Using a Grey-card Reference
That's true for a grey-card that's intended for exposure control. The theory says that an average scene is 18% grey (tonally). In truth only Ansel Adams wanted 18% - for his own reasons. In the real world an average scene is about 13% grey and all digital cameras conform to that percentage for meter...
- 2010-02-13T10:21:28-07:00
- Forum: Users
- Topic: White Balance Correction Using a Grey-card Reference
- Replies: 36
- Views: 60344
Re: White Balance Correction Using a Grey-card Reference
Hello again. I've solved the problem. It goes like this... convert MAIN.JPG ^ ( +clone ( REFERENCE.JPG -gravity Center -crop "128x128+0+0" -scale "1x1" -negate ) +dither -interpolate Integer -clut ) ^ -compose Overlay -composite ^ FIXED.JPG The white reference target will be disc...
- 2010-02-12T10:50:28-07:00
- Forum: Users
- Topic: White Balance Correction Using a Grey-card Reference
- Replies: 36
- Views: 60344
Re: White Balance Correction Using a Grey-card Reference
Hi to you. I should have explained myself better. It's standard practice with some photographers to take a shot of a reference grey-card at the beginning of a sequence of images. This reference shot becomes the guide to the colour cast in all the images until the light is different and requires a ne...
- 2010-02-12T08:33:00-07:00
- Forum: Users
- Topic: White Balance Correction Using a Grey-card Reference
- Replies: 36
- Views: 60344
White Balance Correction Using a Grey-card Reference
Hi. Thanks for the forum. There is a well-known way of correcting the white balance of any photograph using a second photograph, with neutral grey target in shot, taken under the same lighting conditions. The question is simply how to do this using IM. I thought of doing this by averaging the colour...