Load luminance mask for luminance sharpening

JK
Posted By
Jim_Kahnweiler
Sep 23, 2008
Views
1484
Replies
30
Status
Closed
I’m using CS3 for Mac and I thought Cmd-Tilde would load a luminance mask. Load the selection into a new layer, repeat the mask and invert it and load it again. Sharpen both new layers and it’s a clean way to sharpen. But… the Cmd-Tilde has no effect. Can anyone help? Thanks.

JimK

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J
JeffN
Sep 23, 2008
Try option+cmd+tilde
Maybe abobe changed it

JeffN
JK
Jim_Kahnweiler
Sep 23, 2008
Yeah, that’s what I thought, but it doesn’t work in CS3. Do you know if there’s another way? Doesn’t Photoshop have at least 3 ways to do anything?

JimK
R
Ram
Sep 23, 2008
CTRL tilde
JK
Jim_Kahnweiler
Sep 23, 2008
Ramón

That doesn’t work, either. Any other suggestions?
JM
J_Maloney
Sep 23, 2008
Control-click on RGB.
JP
jean_p
Sep 23, 2008
command-option-shift-tilde
AS
Ann_Shelbourne
Sep 23, 2008
Jim:

Cmd Option Tilde definitely works in CS3 on OSX 10.4.11.

Perhaps you are using Leopard and it’s different?

Also try: Cmd Option Shift Tilde.
AS
Ann_Shelbourne
Sep 23, 2008
I started to do something else before I remembered to press the "Post Message" button and Jean got there first!

🙂
JM
J_Maloney
Sep 23, 2008
I had to go into keyboard shortcuts in System prefs and kill off the "move focus to the window drawer" shortcut to have PS recognize the tilde key command.

J
JK
Jim_Kahnweiler
Sep 23, 2008
Thanks so much for all your responses. (Good hearing from you, Ann, as always.)

Well, the prize goes to J Maloney for noting that MacOS has a system keyboard short cut that prevents the Adobe short cut from working. I guess there’s no other way to invoke the Luminance mask except with the keyboard commands.

So, I got it to work by disabling the MacOS shortcuts.

Now, another question for you gurus:
When used alone, the both short cuts create the same mask. When I use one and then the other, the mask out line changes, but when I create an new layer based on the mask, they look identical. Quick Mask seems to be the same mask, too. What’s going on here?

Thanks.
MR
Mark_Reynolds
Sep 24, 2008
"I guess there’s no other way to invoke the Luminance mask except with the keyboard commands" – yes there is, you just command click on the composite RGB channel in the channels palette.
JK
Jim_Kahnweiler
Sep 25, 2008
Thanks, Mark. I’m not sure I know about your sharpening technique using blending sliders.

The way I’m doing it with luminosity is to select the mask, copy to a new layer. Make the background layer active and select luminosity again, invert the selection and create a second layer. Sharpen both luminosity layers with unsharp mask and reduce opacity as necessary. I think that’s the way Photokit does it, though I’m only guessing.

Could you let me know how you are using luminosity. Or, post a link to a tutorial.

Thanks.

Jim
MR
Mark_Reynolds
Sep 26, 2008
You can achieve the same thing this way –

• Make a copy of your layer (command J)
• Sharpen the copy using your Unsharp settings
• duplicate your sharpened layer – now you have three layers one original and two sharpened copies • Now on the first sharpened layer choose Layer Blending Options (there are a variety of ways to do this biut the easiest is double clicking to the right of the layers NAME in the layers panel.
• As you move the sliders at the bottom it is dropping out the sharpening effect in the shadow or highlight areas based on luminosity. Use the option key to split the sliders to control how much tail off you get. As an example to visualise what is happening only, make a solid color layer and do the same thing with blending options choosing underlying layer to see the effect visualy. See how editable it is?
• You use one of your sharpened layers to sharpen the highlights and another to sharpen the shadows

Theres an even better way using Smart Objects now, but thats going to take too long to explain
JK
Jim_Kahnweiler
Sep 27, 2008
Wow, Mark, that works great! I never realized there could so much control with for sharpening without using a mask.

Thanks.
MR
Mark_Reynolds
Sep 27, 2008
Be very cautious of trying to learn tricks and techniques from books or websites – most of its not very good. Much better idea is to study the software itself, in this way giving you a full toolkit to design your own techniques.
JK
Jim_Kahnweiler
Sep 29, 2008
I agree, tutorials can be hit-or-miss. But, they have provided me a place to begin and a way to explore the capabilities of Photoshop. The luminance sharpening technique to which I refer in this thread came from a tutorial by Katrin Eismann, who, in my opinion, must be one the premier Photoshop gurus.

By the way, I’ve blundered into an alternate Keyboard Shortcut to invoke the Luminance Mask: Opt-Cmd-1 or -Number Pad 1. Now, there’s a command that won’t conflict with the OS keyboard shortcut! You’re right, just playing, or making a mistake, will provide much insight.
JM
J_Maloney
Sep 29, 2008
Opt-Cmd-1

That’s the red channel, not luminosity. Can you provide a link to Katrin’s tutorial?

J
JK
Jim_Kahnweiler
Sep 29, 2008
So, does that mean I’m selecting the luminance mask for the channel? Opt-Cmd-2 must load the Green, and Opt-Cmd-3 must load the Blue. Now that we can do with these masks?

If you convert to lab, take the Luminance channel, load the masks (with Opt-Cmd-Tilde) and sharpen that selection with unsharp mask, the image looks great.

I did a quick google and couldn’t find the tutorial online. I’m at work, but I’ll look in the Eismann book I have on my shelf.
JM
J_Maloney
Sep 29, 2008
So, does that mean I’m selecting the luminance mask for the channel?

Yes.

If you convert to lab, take the Luminance channel, load the masks (with Opt-Cmd-Tilde) and sharpen that selection with unsharp mask, the image looks great.

Bruce Fraser recommended sharpening much as Mark describes and then setting the blending mode of the sharpened layer to luminosity (all in RGB). I don’t think this matches exactly the move to LAB, but it is supposedly very similar (enough for hacks like me).

J
TL
Tim_Lookingbill
Sep 29, 2008
The amount of contrast sharpening performed with Luminosity blend mode will desaturate colors that transition from light to dark, so keep an eye on that.

The main reason for Luminosity blend mode when sharpening is to prevent chroma noise and chromatic aberation along edges from becoming amplified.

Contrast sharpening is when you set USM Amount to 10-20 and Radius to around 50-70 where the level of Radius depends on the resolution of the image.

Using Mark’s technique of Blend If works incredibly well with contrast sharpening also.
MR
Mark_Reynolds
Sep 30, 2008
Don’t give the whole bag of tricks away Tim
JM
Jonas_M._Rogne
Oct 15, 2008
Tim gave away a good tip about increasing local contrast by using very high radius setting on a sharpening filter… I use that daily! 😀

Here’s another for the actual sharpening that I consider to give the best results:

The way I sharpen images is using the high pass filter;
* Duplicate layer
* Blending mode: Overlay 100 % (or linear light at 40 %) * High pass (radius depending on use. E.g. 2 px for press, 0.3-0.4 for screen) * Desaturate (to avoid color noise etc. being amplified).

Adjust layer opacity do adjust the amount (usually not needed). Add edge masks to avoid affecting surfaces, etc.

And yes, you can do this non-destructively with smart objects as well.



If you want a simpler way just use the Smart Sharpen filter (same radius settings, uncheck "more accurate". Could be an idea to desaturate this effect as well (or blending mode: luminosity).
MR
Mark_Reynolds
Oct 15, 2008
Jonas – as far as I’m aware that high pass sharpening method does precisely the same as the radius slider in the USM filter. Its one of the long running myths that somehow using High Pass on an overlay layer is a better method.

Maybe I’m wrong, but I have yet to see any practical explanation of what this method is supposed to be doing better. USM has the added advantage of having a threshold setting, which High Pass doesn’t have

You can obviously also fade or blend Unsharp Mask using Luminosity to avoid color distortions. This is another long running myth generally.
B
barkerjohn
Oct 15, 2008
Jim, It’s just possible you have the same problem that I had. A while back I had a problem getting the tilde key to function as I expected it to. I had recently changed keyboards and found that my keyboard settings were incorrect. Check in system preferences -International- Input menu to make sure you have the correct keyboard selected.
JK
Jim_Kahnweiler
Oct 15, 2008
To Jonas and Mark

I use the High-Pass method a lot, especially with fine detail images. It seems to avoid halos better than USM. I used it before Smart Sharpen and Smart Layers because it was non-destructive. Great for a master file that had to be resized and re-sharpened depending on use. I’ll have to try the desaturate the next time I use it. That’s a new one for me.

Also, I’m not sure what you mean by edge masks. Could you explain, please? Thanks.

To Bakerjohn

Thanks. I found the problem I had initially was caused by the default MacOS keyboard shortcut overriding the Photoshop keyboard shortcut to load the luminance mask. I went to Keyboards preferences and disabled it.

Jim
JM
J_Maloney
Oct 15, 2008
Also, I’m not sure what you mean by edge masks. Could you explain, please? Thanks.

Make a new channel based on luminosity. Filter… stylize… find edges. Blur and levels to get an edge mask. You can blur before the filter too.

High pass also finds edges, and you can drop your high pass layer over black (then invert) and white in hard light, then multiply the merged results to get softened edges. This way you don’t get double-lined fine detail (eyelashes that seem to double upon sharpening).

J
MR
Mark_Reynolds
Oct 15, 2008
Ok since its a while since Ive been into sharpening I’ve had to do some tests just now – I’ve compared USM filter with high pass using the same radius setting. This comparison I’ve done done directly using 2 methods one using difference blend, and also using a mathematical method using Apply Image.

Turns out I seem to be wrong in my post earlier. There is in fact no way to directly reproduce the effect of using the High Pass filter using USM. It does have a slightly different effect. Very subtly different, and not necessarily better or worse. On lower res images and fine detail High Pass seems to be slightly better visibly at producing less sharp haloing. Which is what Jim has said.

In my difference tests the whole image surface is different though, so it means that the algorythm in High Pass must be a different one.

Well you learn something every day.
DK
Doug_Katz
Oct 16, 2008
Takes a big man to make those tests, report the results and make apologies. We don’t see that often enough here.
R
Ram
Oct 16, 2008
What Doug just said.
JK
Jim_Kahnweiler
Oct 16, 2008
Mark, thanks for the test and report.

We seldom see anyone acknowledging mistakes and I greatly appreciate your candor. Photoshop has to be the deepest program in computerdom and we’re all here to learn.

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