LR4 still inadequate since doesn't have Levels Tool

Started Jul 7, 2012 | Discussions thread
andrewD2
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Re: LR4 still inadequate since doesn't have Levels Tool
In reply to Ysarex, Jul 14, 2012

Ysarex wrote:

Levels is neither a dumb-down version of Curves nor is it a subset of Curves. Shifting the midpoint slider in Levels produces a result that has no corollary in Curves. You can't place a node on the Curve and shift it in any way to exactly replicate that Levels result.

The gamma adjustment you are making with the midpoint levels slider can be matched with a curve, needs to start off steeply and level off. Similar to what you see here:

http://en.wikipedia.org/wiki/File:GammaFunctionGraph.svg

I managed to get a curve to match a levels adjust with the midtone slider set to 2.

So the midpoint slider is a very specfic curve but it can be described by a curve.

I've saved a .PSD file where you can toggle off a layer group that uses a curve and it pretty much matches the midtone lvl adjust. Perfect will be limited by the 8bit precision of the curves dialog but its near enough not to matter.

Tried the same two adjustment on another image and could not tell the difference between the two at all.

Work using that curve shape and see if you can do it. Dropping a few smaple points and reading off the info will help do it experimentally or you can try and do it more mathematically.

Cheers,
Andrew

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