Luminosity blending the best techniques?

[mayday]

Another topic Markzebra touched on in another thread was the difference between colour and tone so I want to open a thread on luminosity blending this is a method used to improve tone.

A simple way of doing this with skin is to use a channel mixing layer set to mono the green channel +100 (as attached). Then set this to Luminosity blending mode. This often improves the skin tones.

What other Luminosity blending techniques and methods are using?

[Markzebra]

Good idea for a thread Mayday. A great idea for discussion, will be interesting to see what others take on this is..

My input - Although this is quite a crude introduction, to a very large subject.. One way to approach the issue of color and tone is to view them separately and its a good exercise to try balancing them completely separately.

Although at first glance this may seem crude, its not. You can concentrate on tone first by creating a grayscale, where the tones are exactly where you want them to be, contrast is controlled. This is where you concentrate on good focus in an image, where the subject usually has good tonal distribution. In CS3 one of the easiest ways is to use a greyscale adjustment layer. In previous versions a Channel mix, or the "Russel Brown" technique can effectively do the same thing in more steps. If using a channel mix the thing to watch for is good gradation of tones in the channels you choose to use, blue (or yellow in CMYK) is usually the worst channel to use for this. Check the histogram. These layers can if you want a quick fix, be set to Lum blend.

The next step can be to reintroduce the original hue values - and control these, Selective color and color blended curves are a good and subtle way of doing this, but again its really too large a subject to cover in one post.

I'm not saying that this is a technique you want to use every day but its certainly a worthwhile exercise

Its not true to say as someone said in another thread that curves are difficult with skin, you just have to use them very subtly. Personally I don't like Color balance or particularly levels as color correction tools. As I said in another thread a few months ago now you can also have all your 10 channels embedded in one file, and thats really limitless power.

[KR1156]

i work with a retoucher that instructs me to mask the skin, then desat it a bit, but not too far, i usually use a hue/sat layer and desat the reds & yellows, and the overall sat like 35% depending on the file.

this step really helps to smooth out the tone and the transitions. especially on digital photography...skin tones and all the hues that it has get very choppy very easily. and there are almost always red/magentaish hot spots here and there.

so, after i desat skin, with that same mask, i add a new curve (color mode) so that i only re-introduce color. i don't shift the original tone.

after that, a new layer with the same mask, this time set to luminosity so the hue does not shift, and i can control the contrast of the skin tone easily.

--if i client says i love the color, but it's too flat...i can easily just go into my luminosity curve and pump it up a bit, without worrying about straying from the color that the client liiked.

[mayday]

Originally Posted by KR1156

i work with a retoucher that instructs me to mask the skin, then desat it a bit, but not too far, i usually use a hue/sat layer and desat the reds & yellows, and the overall sat like 35% depending on the file.

this step really helps to smooth out the tone and the transitions. especially on digital photography...skin tones and all the hues that it has get very choppy very easily. and there are almost always red/magentaish hot spots here and there.

so, after i desat skin, with that same mask, i add a new curve (color mode) so that i only re-introduce color. i don't shift the original tone.

after that, a new layer with the same mask, this time set to luminosity so the hue does not shift, and i can control the contrast of the skin tone easily.

--if i client says i love the color, but it's too flat...i can easily just go into my luminosity curve and pump it up a bit, without worrying about straying from the color that the client liiked.

KR115 this technique is very good for keeping a even skin tone.
Nice workflow tip!

[CaptainHook]

This place suddenly gotten very interesting.
Thanks for prompting it KR, and to Chris too.

I am especially interested in all threads related to color.
The title of this disguised it a litte, but i got here eventually.
I kinda wish there was a sub-forum itself titled 'Color',
but i digress.

Markzebra and everyone, keep it coming!

[cricket1961]

KR

A little different than what I am used to. Different enough that I tried it. Normally I completely separate the luminosity and the color altogether, literally, and place each in their own groups. Every thing is clipped so it is nearly impossible for me to screw it up by adding a density move to the hue or vice versa. I don't do it often so it is a action I made up for when I get old. If I find the action I'll break it down and post it up here.

When I tried your method, I had a little difficulty getting the color back into the image after desaturation. Kind of looked like I had done a fill with color oa (wasn't worried with a mask just to try it out ). I know it probably depends on the image, but is there some kind of ratio that you use to determine how much to desaturate?

Chris

[mayday]

Does anyone ever use Gradient maps to change Luminosity?
I think it can also work well

[Hendrik]

I’m not an expert and maybe not the best approach, but ...

I used the degrunge method on the skin, but with a high radius (3 times the radius you would use to smooth the skin). The texture is not affected and you eliminate the tonal differences in the skin.

[mayday]

Originally Posted by Hendrik

I’m not an expert and maybe not the best approach, but ...

I used the degrunge method on the skin, but with a high radius (3 times the radius you would use to smooth the skin). The texture is not affected and you eliminate the tonal differences in the skin.

I think you have the wrong end of the stick Hendrik this is not about skin smoothing, its about tone and some of what KR is talking about is colour

[cricket1961]

Mayday

I use gradient maps on a daily basis. Its my second favorite tool. It does work well for luminosity changes if set right. Its also great for masking but thats another thread all together.

As far as lum goes, try this. Default black and white, click reverse, hit ok and then lower the opacity to 0%. Also change the blend mode to Linear Dodge. Now up the opacity in 1% increments and watch the image open up while retaining color. Unfortunately it does change saturation but it is easily fixed. If you click back into the gradient for the mesh and slide the hilite triangle to the left you can limit how the opening up affects your higher end.

There is so much to do with this tool. Its easy to get lost in it.
Chris

[mayday]

Thanks for the tip Chris I would'nt have thought of blending it in that way!

Your right gradient maps can be used to control all sorts of things. I would be very interested to know how you use it to mask though. If you ever get time to explain I would be grateful to hear your method.

[Michel B]

Originally Posted by cricket1961

Mayday

I use gradient maps on a daily basis. Its my second favorite tool. It does work well for luminosity changes if set right. Its also great for masking but thats another thread all together.

There is so much to do with this tool. Its easy to get lost in it.
Chris

I totally agree... because I use Elements, and before I added the plug-in smartcurves, I got used to using gradients maps regularly for luminosity masking as well as replacing curves for tonal adjustments. If you add that there is no shortcut to select highlights, midtones and shadows, a set of gradients for those purposes is very handy. Most of the time, when using hue/sat adjustment I use either masks or duplicate copies above to preserve either luminosity or colour. (Well, I am not very concerned with skin retouch...)

[rovis]

I use the same desat+curve method all the time. master desat is usually -35 to -40. I'm using the curves layer in normal mode, that way I can add color to the highlights of the skin by tweaking the hi endpoints of the curves. If the color is too uniform, then I just drop the opacity of the desat layer. The desat+curve layers also even out color changes introduced by D&B, when kept on top of the D&B layers.

[jenniferfrances]

For selective sharpening...in most cases this technique is very subtle but when working with strong colors this works like a charm.

unsharp mask to your liking
edit>fade>reduce opacity>set mode to luminosity.

done.

[MacBurg]

Not too sure if anyone has heard of these actions before, I did a quick search here and nothing showed up, kinda strange as I thought they were common place in most peoples action palette.

I use Luminosity Masks on pretty much every image, mostly with curves and levels but they see plenty of use elsewhere in my image. I haven't had the chance to try out Tony's Saturation Masks, but thats for another thread anyway.

[KR1156]

Originally Posted by cricket1961

KR

A little different than what I am used to. Different enough that I tried it. Normally I completely separate the luminosity and the color altogether, literally, and place each in their own groups. Every thing is clipped so it is nearly impossible for me to screw it up by adding a density move to the hue or vice versa. I don't do it often so it is a action I made up for when I get old. If I find the action I'll break it down and post it up here.

When I tried your method, I had a little difficulty getting the color back into the image after desaturation. Kind of looked like I had done a fill with color oa (wasn't worried with a mask just to try it out ). I know it probably depends on the image, but is there some kind of ratio that you use to determine how much to desaturate?

Chris

no particular ratio chris, just use my eye, the most important tool in our arsenal! it is something that needs a mask, OA it doesn't work well.

If i feel im looking a bit monotone, or lets say the original makeup on the face was perfect before hand, i will just brush on my desat mask to bring the original color back.

it's not the gospel, just another trick.

[cricket1961]

Originally Posted by MacBurg

Not too sure if anyone has heard of these actions before, I did a quick search here and nothing showed up, kinda strange as I thought they were common place in most peoples action palette.

I use Luminosity Masks on pretty much every image, mostly with curves and levels but they see plenty of use elsewhere in my image. I haven't had the chance to try out Tony's Saturation Masks, but thats for another thread anyway.

I have heard of him. Found his site by accident about a year ago. Read his tutorials with interest as they use the same techniques I have used for years to make density masks for color moves. Density is just my word for luminosity for these masks as they are made up of the various density differences in each channel of an image. They are quick and easy to make as long as you remember the order in which to click on channels and when to inverse you active selections.
I use them for hue moves, density moves, detail recovery, adding and subtracting saturation. The list goes on. People should try them out. They'll teach you a lot about an image.

Chris

[MacBurg]

Here are some examples of the Luminosity Masks in use -

Lights

Darks

Midtones

.

[JavierT]

Amazing thread.

This technique (luminosity mask is fantastic). This kind of information is that i have been looking for. Thanks a lot

And thanks to KR to invite us to speak about something different than skin.

[CaptainHook]

I made my own action set to create luminosity masks quite
a while ago now. Use them on just about every image.
I made actions for saturation masks also.
Great stuff.

[saby]

Originally Posted by cricket1961

...
As far as lum goes, try this. Default black and white, click reverse, hit ok and then lower the opacity to 0%. Also change the blend mode to Linear Dodge. Now up the opacity in 1% increments and watch the image open up while retaining color. Unfortunately it does change saturation but it is easily fixed. If you click back into the gradient for the mesh and slide the hilite triangle to the left you can limit how the opening up affects your higher end.

There is so much to do with this tool. Its easy to get lost in it.
Chris

At last we arriwed to our favorite d&b, but this is a very usefull tip Chris, this is what I use, seems about Ur technique:

[cricket1961]

Saby

It looks good. Almost HD.

Did you try it using the gradient map as I described? The way you used the blend if controls mimics the way to adjust the gradient used in the gradient map.

If you use the gradient map method you can add the additional blend if controls that you used for more flexibility.

If anyone is confused about the method I used I'll gladly put something like Saby did for a visual as soon as I can get a break from working.

Chris

[mayday]

Chris I guess you can use you Gradient map technique for darkening on linear burn mode?

[Daviskw]

Hi mayday

Below is another technique essentially the same as yours I believe but a different way of achieving it...This by Dan Margulas

Duplicate the background

On the duplicate use apply image

Set the source channel to green and the blending to normal

Adjust opacity as desired... I usually leave it at 100 percent.

Change the duplicates layer mode to luminosity and adjust opacity as needed.

Butch

[cricket1961]

Originally Posted by mayday

Chris I guess you can use you Gradient map technique for darkening on linear burn mode?

Yes you can. Many different things can be done with the blend modes. Then you can get into using different color gradient maps and blend modes.

Chris

[saby]

Originally Posted by cricket1961

Saby

It looks good. Almost HD.

Did you try it using the gradient map as I described? The way you used the blend if controls mimics the way to adjust the gradient used in the gradient map.

If you use the gradient map method you can add the additional blend if controls that you used for more flexibility.

If anyone is confused about the method I used I'll gladly put something like Saby did for a visual as soon as I can get a break from working.

Chris

exactly, that was what I've tried and Ur way there is one more softening possibility, that's great

[mschwartz]

Chris,
If you could put some screen shots up similar to Saby's it would be quite helpful.

Michael

[Markzebra]

The advanced blending sliders are a much underused shortcut to a lot of these "density masking" techniques - remember you can also split the channels and blend them seperately. In practice theres not a lot of advantage in creating layer masks, when advanced blending is doing the same thing. These layers can also sit on top of your image non destrucively, and react to any base retouching below them. The only disadvantage with this technique over gradient map is that I've found unless the source is very pure it can create posterisation on 8 bit images though.

Interesting to see someone doing the same thing as I do sometimes, putting two layer sets one for tonal information and one for color Most blend modes can also be simulated with Curve adjustments - the linear dodge technique for opening an image up that Chris describes earlier can be simulated with a curve that simulates linear dodge. This curve has a straight line, hence "linear" dodge. Saves duplicating pixels. Again this is controllable with opacity - you can even find a curve that sits half way between a color dodge and linear dodge- in this way controlling the saturation issues that Chris rightly mentions

Yes the whole topic of Gradient maps, and their uses is a fascinating one, and I'm reading everyones experience with interest

[JavierT]

I am reading with interest too, but sometimes I have problems to understand the workflow you posted. I have to make an effort to process the information. The problem is that you post faster than I process, LOL.

Anyway, is nice see the sucess of the new threads.

Chris, I know you are very busy, but some kind of help (screenshots) are welcoming. I am discovering the powerfull of gradient maps.

Thanks.

[Kitkuare]

Great thread, hope to read more!
Devon