On 10/31/2012 09:26 PM, Ulrich Pegelow wrote:
Hi!
>> I've found that difference blend module would be useful
>> to get something like a "visible mask" when using the
>> sharpen plugin. This blend mode gives information about
>> the impact of the sharpening in the image, with white
>> lines that get lighter when you give more force to the
>> sharpening. However, the difference mode gives a strong
>> blue screen, so that white lines are difficult to see. Is
>> there a way to change that blue color? It would be nice
>> to have a neutral grey instead, IMHO.
>
> this is a known issue. Blend mode "difference" works well
> for modules in RGB color space but gives a blue tint in
> Lab (that's the color space where sharpen operates in). I
> have not found a good way to handle with this issue yet.
> Software like Photoshop solve this problem by not offering
> this blend mode for images in Lab.
Is there currently a way to see/work the individual channels
in dt?
Though it is a bit "abstract" to work only in L, a or b
displayed in grayscale this sometimes helps, and especially
sharpening should work on the L-channel (mostly at least),
so "just display L" could probably already solve the OPs
issue.
When I use Lab sharpening in <this other great software>, I
usually decompose the image use unsharp mask on L only and,
if there is some noise, blur a and/or b slightly using a
gausian e.g. Though there's a plugin for Lab sharpen, I
admit that I usually do it manually, since I understood how
it works. Simply cause I can see the effect easier. I think
this is probably what the OP intends. AFAIK I can not this
kind of workflow replicate that in dt at the moment, as
sharpen works in Lab but on all channels simultaneously,
right?
> If someone has a good idea, I am fine to implement it.
> Probably we would need to limit ourselves to the L channel
> and sacrifice a and b.
From my gimp-work I think displaying the cannels
individually could work pretty well.
--
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Alexander Wagner | Ignorance is Strength.
|
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/ In practice: USA, since 2001
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