GNOME Bugzilla – Bug 152713
"watchpoints" for curves / image info
Last modified: 2004-09-17 11:27:48 UTC
Please could there be a way to display RGB values for a selected pixel (or 3x3 or 5x5) that updates as the curves dialog is used? ctl-shift-i -> image info window is useful, but frustrating in that there is no feedback loop to see how a pixel/channel value changes with the curve modification. I understand the photoshop equivalent is to shift-click with the "eyedropper" tool to display up to 4 such info panels. I am envisioning either: (a) a way to make multiple image-info (extended tab) windows, where the extra ones don't update the values when the mouse moves, just stay focused on a selected point. (b) R,G,B values at the bottom of the curves dialog which would present the pixel values corresponding to the click-drag mouse position (and vertical line in the curve pane). A button next to the values would 'lock' a position for monitoring and (ideally) create another such row of values so we could see several positions update as the curve is modified. (Don't know how this might work if one were in a 4+ value colorspace like CMYK in a future Gimp) Not having this feature makes it hard to remove colorcasts by working on neutral regions as described in e.g. the Margullis book. I'm really sorry if this is already implemented somewhere, but I've not been able to find it. thanks, rob.
A very similar request is in bug #137776 already.
Yes, sorry I missed it, this would be the same functionality and I would be happy to see it implemented in any of the suggested ways. Seems like saving as part of the XCF would be "nice but not required", also the 'sticky tooltips' would need to be movable (perhaps this is obvious?) to avoid obscuring the image. As all the reporters seem to be into the Margulis book, the option to set sampling to average over a 3x3 or 5x5 patch is one that he recommends taking.
What's the "Margulis book"?
Professional Photoshop 5 The Classic Guide to Color Correction by Dan Margulis. Recommended on various 'GIMP books' sites, found mine on Amazon used books. A sample chapter from the current edition (photoshop 7) is at http://www.ledet.com/margulis/articles.html It is strongly focused on CMYK, but that doesn't seem to matter -- it's really the "what and why" of color correction, with the "how" mostly relegated to 'oh, any good graphics program would have a way to do this'.
The sample "chapter 2: By The Numbers" is perhaps the most relevant in the book (based on knowledge of the PS5 edition) for the topic here.
Thanks for the link. As you agreed this is the same as bug #137776 I'm resolving this one as duplicate. *** This bug has been marked as a duplicate of 137776 ***