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Doug Dolde
18-Nov-2006, 17:44
Tony Kuyper just published an article and a free set of actions for luminosity masking. I am finding the midrange masks to work exceptionall well for increasing the midtone contrast with a curve.

Many thanks to Tony for this terrific technique.

http://www.goodlight.us/writing/luminositymasks/luminositymasks-1.html

Doug Dolde
18-Nov-2006, 18:33
you are totally wrong on this

robc
18-Nov-2006, 18:35
why?

Doug Dolde
18-Nov-2006, 18:40
read his article....the masks create perfectly feathered selections unlike any of Photoshops selectition methods. it works...

robc
18-Nov-2006, 18:45
OOPS:o

Sheldon N
18-Nov-2006, 19:10
I have to say that this is the best thing I have learned in Photoshop this past year. I just spent 30 minutes reading through this, figuring out what it does, and building in the actions.

The midtone masks are amazing.

Thanks Doug!

Jack Flesher
19-Nov-2006, 13:23
Hey, nice find Doug and thanks for sharing! This is a very nice action set and useful in several ways.

Cheers,

Frank Doering
19-Nov-2006, 15:28
1. You can create these kinds of masks more straightforwardly. Load your RGB or gray channel as a selection (command-click on a Mac), then save this selection as a new channel. Now use the curves tool on the new channel. A bell-shaped curve, for example, gives you a midtone mask. The width of the bell determines the extent to which shadows and lights are being masked.

2. Using these kinds of masks (call them "density dependent") on a curves adjustment layer does not purchase any effect that couldn't be had by manipulating a curve without masking. The reason is that the output value for each pixel is in the end a function of nothing but its input (underlying) value. The input value first determines the mask density (that's how the mask gets constructed), which in turn determines the output value as a certain mixture of curve-adjusted and input pixel value. What we get, in effect, is a mapping from input into output pixel values that can be represented as another adjustment curve, namely a density-dependent mixture between a 45 degree straight line (the unchanged underlying layer) and the curve on the adjustment layer, a curve that falls somewhere between our adjustment curve and the 45 degree line.

3. Such density-dependent masks can, however, be extremely useful on layers that are manipulated in ways that are not simply density-dependent. Sharpening layers are the first that come to mind.

Jack Flesher
19-Nov-2006, 20:53
1. You can create these kinds of masks more straightforwardly. Load your RGB or gray channel as a selection (command-click on a Mac), then save this selection as a new channel. Now use the curves tool on the new channel. A bell-shaped curve, for example, gives you a midtone mask. The width of the bell determines the extent to which shadows and lights are being masked.


Sure, you can do that -- but each separate action chooses its same luminosity value each time and there are 14 of them! Using them, you quickly learn the range of tones each action selects and it becomes a repeatable part of your workflow. AND you can still tweak the masks individually like you mention by using a clipping-adjustment layer on top of them...

So, you can use the mask directly on an adjustment layer and you can fine tune the luminosity in very specific parts of your image without any visible transition -- kind of like adding 12 more zones to the shadow/highlight tool and making it a full-spectrum shadow/midtone/highlight tool! Or you can use them as masks between layers and you can make seamless HDR blends. The transitions are so smooth you can use some of the different blend modes to further tweak effects like hue and saturation along with luminosity and contrast. Very cool IMO. Two thumbs up!

Only downside is just what Doug said -- you might have a lot of files you want to reprocess ;)

Cheers,

Jack

Doug Dolde
19-Nov-2006, 21:00
you might have a lot of files you want to reprocess ;)



No kidding....most of my weekend so far and I'm not done yet. The good thing is I dont have to reprocess whe whole file in most cases. The tweaks can be added on at the end of an already processed file......some of which I had been wishing for a solution exactly like this one.

neil poulsen
20-Nov-2006, 00:55
I use feathered luminosity masks with curves for highlights, and then use them again inverted for shadows. I learned this technique from Dan Burkholder in a workshop.

I find they are terrific for enhancing an image that doesn't have high contrast. One can bring out delicate subtleties in the image. They don't seem to help a lot with high contrast images.

QT Luong
20-Nov-2006, 12:43
That's a neat technique. What would be the easiest way to use one of those masks to restrict high radius sharpening to the mid-tones and shadows, therefore preventing highlights from being clipped ?

Ed Richards
20-Nov-2006, 12:54
> Using these kinds of masks (call them "density dependent") on a curves adjustment layer does not purchase any effect that couldn't be had by manipulating a curve without masking.

Frank - Just to make sure I understand, is the effect of these masks the same as using fixed points to prevent the brightness curve from moving so you can adjust portions of the curve?

Frank Doering
20-Nov-2006, 15:11
Ed, here are two files to illustrate the point that using a density dependent mask on a curve adjustment layer comes to the same as using a somewhat wiggly curve and no mask:

http://www.doeringphoto.com/temp/wiggly_curve.psd
http://www.doeringphoto.com/temp/midtone_mask.psd

Frank Doering
20-Nov-2006, 15:15
Addendum: maybe your browser tries to open the files instead of downloading them. On Safari, I have to hold down the option key when I click the URL.