Joachim Smith wrote:
Hello Gimp Wizards,
I am not a gimp wizard, just a user, so forgive me if I cannot answer
all of your questions. I use gimp 2.3.7 so there might be a few
differences between my answers and what you actually have in your version.
However, being raised on Photoshop but a newbie with Gimp, I'm stumped by some
of Gimp's functions. Please bear with me...
1) I can't seem to find any option for a continuous numerical readout of RGB
and greyscale values as I move the cursor in the image!
The colour picker tool is the one you want. It is the 8th in the
toolbox. When you select it, notice the tool options tab in the bottom
half of the toolbox window. There you can see an option check-box "Use
info window (Shift)". If you check it or if you press shift while
clicking on the image with this tool, a window will pop up and tell you
what you want.
I have discovered that I can use the Color Picker tool to get readouts if I
click somewhere. BUT, if I invoke a function like Color Correction, the Color
Picker window is disabled and no help at all for checking stuff like clipping
channels or colour casts of areas that should be neutral.
The colour picker can be used from within the main colour correction
tools ("Curves" and "Levels"). Try clicking on the images when you use
the curve tool, it will put a point at the corresponding coordinate. In
the Levels tool, there are some colour picker icons to set the black,
white and grey points.
From Photoshop I'm used to always having readouts available in the Info
palette. In Gimp, it seems that though I get all kinds of positional data in
the lower left image frame corner, there's no color data readout option.
2) The Decompose to... and Compose to... functions are intriguing and
potentially useful, BUT so far, I haven't been able to, say, Decompose an RGB
image to LAB (for sharpening just the L channel or for adjusting gamma without
colour saturation buildup) AND then Compose the layered image back to RGB!
When I try, I get truly weird colours and I get the impression that Decompose
to... and Compose to... don't work in a complementary or transparent manner.
This makes me wonder what these functions are meant for.
Ouch! L A and B channels. At least the gimp should be corrected to spell
this correctly ;) (as everyone knows, L*, a* and b*)
I cannot help you on that one, since my compose plugin just crashed when
I selected LAB in it... Good reason not to use unstable versions ;)
Wait... well, I can use "Recompose" and it works fine. Did you assigned
the right channels or images to the L* a* and b* components in the
compose windows ? Are you sure you chose LAB and not RGB when recomposing ?
So, again, there might be something I'm just missing, being weaned on
Photoshop, and if anybody could set me on the right track, I'd be most
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