Skip to main content

Luminosity Masking in Photoshop

Lesson 2 of 9

Making Luminosity Masks

Blake Rudis

Luminosity Masking in Photoshop

Blake Rudis

Starting under


Get access to this class +2000 more taught by the world's top experts

  • 24/7 access via desktop, mobile, or TV
  • New classes added every month
  • Download lessons for offline viewing
  • Exclusive content for subscribers

Lesson Info

2. Making Luminosity Masks

Lesson Info

Making Luminosity Masks

So, before we even begin doing this on any of our photographs, I have to explain the stuff that I just explained, okay? In a way that we can all understand it, which is sometimes the most difficult part. (laughing) So, here we have the luminous value of pixels. So, zero being black, 255 being white, and 128 in the middle being your mid tones, okay. These numbers, 287, they're just arbitrary numbers to show you that somewhere in between zero and 128 lives another value of a pixel. Now, these pixel values from zero to 255, that's a concept that we think about in terms of a pixel, a pixel can only be anywhere from zero to 255. If it's below zero, it's basically non-existent data. If it's above 255, it's basically non-existent data. That's where you get the clipping warnings and the highlight blow out warnings, where it's like (beeping) you're going above 255, stop. Zero to 255, it also exists in colors. Your red color, your green, blue. So, to make any color, you need some combination of ...

RGB or C and Y that involve zero to 255, okay? So, every pixel, essentially, has that zero to 255 value to it and that's essentially how we create these luminosity masks, is from the existence of luminosity. So, by default... The traditional luminosity mask is going to select anything that has a luminance value. So, if it's at zero, is it gonna be selected? No because there's nothing there but what gets selected and how that gets selected transitions from zero to 255. So, areas of your image that are actually in this portion of the graph, so to speak, will be a more robust version of the mask. So, typically when we paint a mask on our image, we paint with black and we paint with white, correct? Well, when you're painting with that white, it doesn't do what things like Adobe Camera Raw and Lightroom do, where if it senses a pixel that's a value that you didn't start with, that it's gonna go, you know, the auto mask feature? We don't have that in Photoshop. This is essentially taking that concept of the auto mask and bringing it into Photoshop. Taking the concept of the auto mask that's in the brushes and the local adjustments right into Photoshop. So, to do this we have to step into the world of channels, okay. How many people play in channels? Okay, we've got a couple here that are not afraid to go into the depths of channels. I'll be honest with you, I don't play too much in channels. It's just not really where I do things. But that's okay. So, if you look at channels, if we had any colors in here, it would show you what the red channel would look like, the green channel would look like, and the blue channel would look like within what actually looks like what? A mask, right? So, this RGB channel, this RGB channel is actually, we can just rename it, right off the bat, luminance because that is where we get our luminance values for the image to build our initial mask. You can see over here it says control two. We press control, alt, two. Just a clever way of making that selection. If we wanna make a selection for that luminance value, we can just press control and click on that RGB, and that's gonna make a selection for all of the luminance value in the image. We can also do this. So, if we press control, alt, and two. That is a way that we can hop into there without having to control click on this RGB channel. So, if you're working on it, you're gonna see me do this. And I'm getting glossy eyes already and I love it because this is a topic that's just like, (clapping) it's kind of like, oh, man, how do you teach this one? You know, it's like, I wanna rip my eyeballs out for you. (laughing) But you'll see my method here in a second, okay? So, by pressing control, alt, two, at any time, you can grab the luminance value as you edit, which is a really important thing to understand. If you're writing notes down about how to make a luminosity mask and you don't want to then turn to channels, just kind of forget that for a couple minutes, okay? Because I'm gonna show you the Blake way and it doesn't involve channels. Again, it might not be the traditional thing and I'm ready to go to social media for you on that but if we press control and click on that RGB, we get a traditional luminosity mask. If we were to come down here and click on this mask icon at the bottom, that mask icon is going to create an alpha channel at the bottom that is, essentially, the luminance value. So we can actually call this highlights because it's gonna be the highlights. Okay? On the flip side, if we wanted the shadows, how do we get the shadows? Well, now we've got the highlight channel, we need to just know the hotkey to invert a selection, which is control, shift, and I. That will invert the selection. So, now if we make a mask for that, we now have shadows. And we can see that by the mask. It's kind of hard because I'm using a gradient at this point, so you're looking at a gradient and you're looking at a gradient mask on top of a gradient mask. When we start getting into image editing, you'll understand but what I wanted to show you, here, is just the pixel values that are being selected, especially now when we look at shadows. It looks like things are inverted. That's because this mask that we've created, this is the portion that's gonna affecting because that's the white part, okay? It's white transitioning into that black. Now, the traditional method to doing traditional luminosity masking is essentially to make six of these masks for each one. So, six for your highlights, six for your mid tones, six for your shadows, and if you wanna get even crazier, you can do eight to 10. You can do 15 if you want, as long as that data is available in there but in order to make those masks, if we were to go and control click on that RGB channel, now how do we make a lesser selection for our highlights? Well, we do that by making that selection and intersecting with the actual highlights. Have I lost you yet? Please say yes, okay, because I want you to realize how convoluted this is. We press control, shift, alt, and then click on the highlights, and then make another mask. This is essentially highlights. If I could spell, my cursor's getting in the way. Highlights two, okay? So, this highlight two selection is actually a smaller selection of highlights. We're getting closer, and closer, and closer to your lightest light areas in the image and you keep doing this. So now, again, we'd intersect this selection. We press control, shift, alt, click on highlights two, notice how this selection gets smaller, and smaller, and smaller. We could change this, we could make a mask, here. Call this highlights three, okay? I really butchered that one but we're just gonna keep going. Press control, shift, alt, and then click on that one, and we're, again, lessening the selection that we're creating from these highlights. It's that control, shift, alt, and E or command, shift, option, E thing. Or, not, that's to make a stamp but command, shift, option, click. You know, it's like, I say this in I think all of my Creative Live classes but if you're ever curious about if Photoshop can do something and you're working in a certain area, and you're not sure if it can do something else in that area, press control and do it. Press alt and do it. Press shift and do it. Press control, shift and do it. Press alt, shift and do it. Press control, shift, alt, and do it. And then it'll do something different at every given time but try to find that actual hotkey for that. You're never gonna do it. So you just do it by like trial and error. Like oh, I can make a selection, well, how can I intersect that selection with a selection of the selection, well let me select control, shift, yeah, okay, got it. So, what I'm trying to get at here is just to show you the traditional way of building these luminosity masks so that you can continue to do this. If you press control, shift, alt, command, shift, option, and then clicked, it would continue to make smaller and smaller highlight selections by what you're intersecting it with those highlight selections. There's a couple reasons why I don't like this way. Number one, we're playing in channels, okay? Now, channels are great because if you go over to layers, those channels don't exist there but any time you wanna get one of those masks, you gotta go over to your channels, you gotta control, click on that channel, you gotta pull up that mask, make another mask, and it's just, it becomes like this, like you spend more time trying to find a luminosity mask that you need than actually doing anything with your photograph. So, there is an easier way to do it. So, I'm gonna go ahead, and just go ahead and delete these because what happens with, what happens when you have all these channels in here, as well, is those channels actually take up a lot of space within your image. So, if you save this as a PSD document with all those channels that you built just for making these masks that you may or may not ever use, now you've got this big ol' file for what? You put two layers in there, it's two gigs, and Photoshop's screaming at you not to save me ever again. So, I don't typically like the channels method. I like the rudimentary, kind of Blake method and I don't know if that can be coined or anything like that, maybe? I don't know. (laughing) So, typically what I'll do with that is I can still make that luminosity mask selection because what's that hotkey that we talked about in the very beginning of this? Control, alt, two, or command, option, two on a Mac. Control, alt, two. I'm not even in channels and it's already making a luminosity mask for that RGB value or that RGB channel. And that's not even getting into the mid tones. To make your mid tones mask, you have to intersect, you have to subtract your highlights mask from your shadows mask, and it's just, yeah. Let's just leave that one for the pros, so they say. So, what we're gonna do with this is now that I've got that selected, I need something that's going to create a mask. Well, you see my little quote over there? Curves adjustment? It's my favorite tool? I always make a curves adjustment layer. It's just my go to. It's like that's, that's my jam, you know? So, I'm gonna click on the adjustments and just make a curves adjustment layer. Because I already had a selection, it's going to make a mask for that curve within that luminosity value, cool? I'm gonna teach you a couple cool things about masks at this point, is that, we've got that luminosity masks selection. We can make a modification to this mask just like we would make a modification to anything else in Photoshop. So, we can modify that mask with using blurs, we can modify that mask with curves, we can modify that mask with levels. So, how you're gonna see that this is so much easier is that if we click on that mask, we go to image, we go to adjustments, we go to levels. I now have a levels adjustment that is gonna make this mask look different. Let me do something a little bit easier for you to see, first. I'm gonna double-click on this curves adjustment layer and, in this curves adjustment layer, I'm gonna click the color overlay. The reason why I do this is that I'm gonna make this magenta, and that's not because I wanna blow your eyeballs out with the color magenta but it's because the color magenta doesn't typically exist, even in the real world, unless maybe you're in like the 1970s with clothing or something like that but even looking around this room, there's nothing in this room right now that is actually that color magenta, right? So, if I were to take a picture of this room knowing that there's nothing in this room that's that color magenta, if I wanna see what my masks look like, magenta's gonna be the best color for that. Now, I'm in something called layer styles. Well, the layer styles, that is the, what tells me what's happening in this layer. If we come up here to the blending options, that's telling me the things of like what blend mode I'm in, what opacity I'm in. What's happening with this layer. So we can actually make this layer have that magenta color overlay on it. It's not making our image magenta, don't be afraid, okay? It's just showing us what our mask looks like at this point. You ever wonder if you could just see a really good copy of that mask? Sometimes we go into something called quick mask mode but then, have you ever edit in quick mask mode and then you try to do something else, and Photoshop's like you're in quick mask mode, you're in quick mask mode. (beeping) It's like okay, well, let me just see what this looks like without having to go into quick mask mode. Again, one of my kind of trademarks. So, press okay. So, now if I click on this mask, this actual mask that's on this curves adjustment layer, I can minimize what this is actually affecting and I can do that by going up to image, going to adjustments, and going to levels. So. Quick little tid bit on levels. Levels are controlled by your shadow areas of what you're telling it to work with, your highlight areas of what you're telling it to work with, and the mid tone areas of that object, right? So, if a mask is essentially made up of contrast, we're talking about luminosity values, here. It's made up of white values, it's made up of black values, and mid tone values in between. We can use levels to dictate how big our mask is. What you'll see is I can drag this over from the left and start introducing more black into that mask, which means that, because I'm introducing more black into this mask, it's restricting how much that mask can actually affect. Which is a little bit different than going into the background of channels, making six different selections, because now I get the pure power to adjust this mask however I want. Especially because I can then, also, go into the mid tones of that, and push the mid tone value of that more towards the shadows or more towards the highlights to get even more out of that mask. Now, you can do the same thing with the traditional luminosity mask selection but what this allows you to do is it says, okay. You want a luminosity mask, Blake? Go ahead, make it. Control, alt, two. You got it. Now, you wanna refine it? Pop a levels adjustment on there. What do you want? Doing it on this gradient is kind of like okay, awesome, you're not really showing me anything, Blake. It's just, you know, data. But what I suggest is, when I stay up late at night, which happens a lot, that's my experimentation time, that's the time that I set aside for me to play around with and I've got tons of graphics that look like this. I mean, I'm a dork when it comes to Photoshop. My wife goes to bed, I'm like, yes, let's go, game on, it's time to go play. And I'll pull up these graphs, and I'll pull up a tool I've never used before, and I'll see how that tool works on that graph because this is, essentially, everything that would be in an image. You can try to pull up a test image and say, well, this image of, let's say, your dog, is always the perfect image to run a test on but not necessarily because do you know what the highlight value actually is in that picture of your dog? Or do you know what the shadow actually is in that picture of your dog? Not necessarily but when I use this, there are no variables. The only variable is how far I push that tool because I have a constant, and that constant is zero to 255. So, now we're gonna break away from that a little bit and we're gonna actually start working on images, so you can see exactly how this works.

Class Description

Luminosity Masking has been the talk of the town for a while in the photo industry—and for good reason. It’s one of the easiest, most effective ways to create striking images that cover a wide range of levels of light. The idea is to separate the luminance data from your image, make a mask and edit the data independently. Blake Rudis will begin by walking you through the basics of Luminosity Masking, and then will address some of the more advanced uses. Once you master this awesome tool, you won’t know how you ever got by without it.

Adobe Photoshop CC 2018



Great great great. What? You can do that? And easy Wow. Wait, you can do that too and so easy too? Wow! (ratta tat tat useful stuff)

Bhaven Jani

Amazing class, so top notch, to the point, and made easy to understand. Yes, luminosity masking is not an easy topic, it is complex, I have been using PS for several years and it still took me a while to get my head around it. But Blake Rudis makes it so engaging and intuitive to understand. And guess what, once you understand LM, you won't be able to edit images without using it. its so powerful. Thanks a ton for this class.

user e5ab02

I've been using PS for quite some time and have avoided this technique BECAUSE it's a bit tedious getting to the meat of what this tool can do. It is however well worth it. Blake has done a great job in presenting this and showing how it can best be used. He DOES NOT in ANY WAY SHAPE OR FORM seem overbearing or egotistical. On the contrary, he seems very approachable and is well aware that what he's teaching is a very dry subject and is trying to make it fun and graspable. Do NOT pay any attention to the reviewer above who says he is...that says so much about the reviewer's insecurities.