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1. Re: recreating merged curves layer by guesswork
Craig F May 18, 2010 9:40 AM (in response to Christian Davideck)There is no formulated way to do it. It's all about a visual adjustment and some recollection on your part.
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2. Re: recreating merged curves layer by guesswork
Jeremy AB May 18, 2010 11:37 AM (in response to Christian Davideck)What about using the Match Color command under Image>Adjust?
It won't give you an adjustment layer but should be able to make the source image look like the PNG.
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3. Re: recreating merged curves layer by guesswork
Christian Davideck May 18, 2010 12:14 PM (in response to Jeremy AB)thank you Jeremy, but /match color/ doesn't give me satisfactory results
(luminosity does obviously not match at all, even colours don't seem to
match too well) plus I'd need a non-distructive adjustment layer.
What I will try next is use the 1x1 color picker and a sheet of paper
and calculate the multipliers I need to go from source to target. I
don't think it will work, but I'll give it a try ...
... don't hesitate if you have other good ideas. Thank you.
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4. Re: recreating merged curves layer by guesswork
Gyno-jiz May 18, 2010 12:16 PM (in response to Christian Davideck)I think the fact that multiple curves were applied will make this difficult.
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5. Re: recreating merged curves layer by guesswork
Christian Davideck May 18, 2010 12:31 PM (in response to Gyno-jiz)@JMaloney:
yes, R,G and B curves were applied. But I also have an R,G,B color
picker so ...
but you are of course right that it will be difficult and probably won't
work ...
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6. Re: recreating merged curves layer by guesswork
Gyno-jiz May 18, 2010 1:05 PM (in response to Christian Davideck)If its just one curve, you can probably do it. But an additional master adjustment might prove too much if the changes were drastic. Still worth a go. Even if you just place the 4 color samplers in quarter tones, you might have some luck. You inspired me to finally get at what Martin Evening was doing below. If you only had a gray strip in each channel...
http://photoshopnews.com/2007/09/05/how-to-express-blend-modes-as-curves/
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7. Re: recreating merged curves layer by guesswork
Christian Davideck May 18, 2010 1:22 PM (in response to Gyno-jiz)If its just one curve, you can probably do it. But all three, plus a master adjustment might prove too much if the change were drastic. Still worth a go. Even if you just place the 4 color samplers in quarter tones, you might have some luck.
As I said above, it doesn't matter whether it's 1 or 3 curves, because
the RGB channels are treated independently (both by color picker and the
curves layer). The master adjustment is more problematic, right,
but theoretically it shouldn't be a problem either, because two curves
can be "merged" ... well, not in Photoshop (I might suggest that as a
feature one day), but mathematically.
Curves are functions. Take an easy function like f(x) = 1.5*x + 2x
this equates to: f(x) = 1.75 * x
(where x = input and f(x) = output in Photoshop curves adjustment)
I have started working with this method and so far it looks promising,
hope it turns out right
I'll let you know
You inspired me to finally get at what Martin Evening was doing below. If you only had a gray strip in each channel...
http://photoshopnews.com/2007/09/05/how-to-express-blend-modes-as-curves/
Looks very interesting. I'll have a look at it one rainy day ...


