LAB Color Mode and Curves
this whole time we've been talking about RGB, but that is not the only color more. That's also see him like a which you guys may know if you do print. But there's also another one called L A B, and usually that would take another hour, and I have to do it. But we're gonna go in 10 minutes. Um, the best way that I could describe it to you is that it's a color motor that separates luminosity from color. That means that you can adjust color without affecting detail, so ah, and actually that's what. But I wrote here, it's the real big differences. RGB, justice, luminosity and color together lab a justice luminosity separate from color. And instead of having RGB values, we have L. A B values. The L Channel controls the lightness. That's where the detail recites. The A channel controls greens to magenta as the blue, the blue control Z blues, two yellows. The values negative values are cool. Positive values or warm zero is right in the middle. That's 50% gray. That's neither of the colors of ...
the channel is just a neutral color. And if you notice the A channel is the equivalent of the 10 slighter on light room or camera. And the blue Channel was equivalent of the, um, temperatures lighter in camera, raw or light room. So that's what we're gonna be working with, Um, in the next few examples, and I have this awesome red couch here. And if I click on channels, you'll see that Oops. I need to change the color mode for the first. If I go into image mode in select laugh color, I was gonna ask me, Do you want to merge all these layers? No, I don't. Um it's gonna at this card. Any adjustment layers that we have that's fine. I don't need them. So I'm just gonna press, okay? I don't want a rast arise. I don't want to flatten the image or do any of our, you know, just flat images or layers? Um, so now we have an image that's no longer RGB. If you look at the tab here, it says l e b lab, and if I go into the channels panel, it no longer says rjb. It says lightness A and B. So, um, I mentioned that detail. It's separate than color. So one thing that you could do is apply some really cool sharpening without affecting the colors Liking went to filter. Um, render I'm sorry. Sharpen, smart, sharpen. And I'm just gonna apply whole bunch of sharpen just so that you could see it's probably way too much a whole bunch of sharpening. But if I click on lab notice that the colors remained the same and all I really did was increase the detail in that image without affecting the color. Um, as you would expect, the curves adjustment layer works differently here. But before we get into that is, um, one thing that I want to show you again the color is separate from the detail. So if you wanted to change the this red couch to a green couch while I would do is press command. I That's between inverted. The the couch is now green. Right now, you don't have any control as to what color that greenness. And that's what we're gonna do in the next step. Hopefully, in the next five minutes, I could show you, um, because maybe you do want a green couch. But that's not the color green that you want. Maybe you want a very, very specific green. For whatever reason, maybe you have one of those clients were like, This is my color swatch right here. And I want this screen and nothing else. Um, so let me just undo that and I'll just select the random green here. Uh, may see maybe something like that, and I'm just gonna paint with a hard brush, like right there. Maybe that's the green that I want. Exactly that green. Oops. I needed to do that on your layer. Let me undo that. So maybe that's a green that I want right there. So how would I go about that? I could click on the eyedropper tool first. I'm sorry. The color sampler to which drops color samples and essentially tells photo shop in the info panel and click and drag this out. It tells Photoshopped the values the L A b values of that green that green has l. A 59 a of negative nb of 56. Now you gotta look at the couch and you gotta find a red that doesn't have shadows and doesn't have, like, highlights. So you don't want to do the highlights here. You don't want to do that. Shadows here. You just want to do sort of like the the actual red on the couch. So in this case, I'm just gonna click, maybe right about here, and we'll just say that's the right, um, read of the couch. Then you can create a curves adjustment layer and you'll notice that the curves now has L. A and B. If I bring up the info panel once again, you'll see the values. Here, on the left hand side are the original values right now on the right hand side, there the same values. But once we start making adjustments of values in the right hand side are gonna make are gonna ever gonna shift. So the values and the left of your originals. So in number one, that's the green number two. That's the couch. So what do you want to do is just simply match the values that we want to match the values And how do we match the values? We can use the curves adjustment layer for that. So by looking at the number one in the number two here, I can click on the curves adjustment layer and were first gonna work with the L Channel. And we wanted to be 59. So I'm gonna click on the point and drag it up in the recent I'm selecting the black and not white is because right now I'm at and I'm trying to get to 59. So if I click on the white one, I can't go up anymore. If I go down, it's lower numbers. So I'm just trying to match those values. I'm gonna go to than the A channel. I'm gonna go to Negative and thea be channel. I need and there it is. What I need to do now is simply create. I'm gonna delete the layer mask. Uh, and then I'm gonna create a quick selection tool around. I'm gonna click on a quick selection to one click and drag around the couch, this electorate red couch and enable it. And there's my red couch. And if I click and drag this up, uh, click on the move tour. Oops, I missed that part, but that's OK, but notice that if I have a right Oh, if I hover right over it, you'll notice that it's exactly the same green. So that's how you would match exactly a color onto um, until couch. That's that Green might have been a little too, too bright. I probably should have shows in the darker green, but I chose that ran them. But, um, but that's Thea. That's the way that you would color match with curves using the L. A. B um color mode. Yeah. And yes, you switched to the L. A B mood. This is only work with you leaving, doesn't it Also works with curves, but it in I feel that it's more intuitive. Um, in the l A b killer moat. Um, just because it, like we mentioned it, separates detail from from color. So if I wanted to I mean, I guess you could also do that in in. Ah, I'm not saying that anything I showed you in the L. A. B color mode doesn't work with RGB. It does. They're just different steps may be similar in some ways, but I just think that in the l. A B color mode, it makes it more intuitive, and it makes it easier to understand because much like I did with the, um, blending modes. You're separating color from luminosity. And by making that separation, at least in my head, I feel that it's easier to understand and easier to do. If you're dealing with the RGB values together, it might get a little more confusing, but similar steps would work in RGB. Um, the other thing that I would mention is, if you're making if you're making an adjustment like this, you are gonna have to go back to RGB before you output. So earlier. You saw that when we changed color modes, we couldn't keep our adjustment layers. And you usually want to keep your adjustment layers because you want to work non destructively. If I were to go back into the RGB color mode, photo shop will tell me that I need to merge the layers and then do Ah and that I can't get my adjustment, Layer said all that fun stuff. But if you want to keep him, you can just make a selection of your layer, your adjustment layer, right click convert to smart object. It's now a smart object is now protected, and if I make an adjustment, I'm sorry, I, uh, change the color mode. I could just like on Don't merge for master rise. I'm back on RGB. You can see that right there. RGB and I have my smart object here. And if I open that up by double click on double clicking on it, um, I still have my adjustment layer here, and I can make adjustments to, um, to the l A or B channels using that, um, smart object. Yeah, and I think that's pretty much all I had. If anyone has any questions or comments regarding curves would be happy to answer them any anything online. We have one back there. Yeah. Okay, so I have a real big problem color correcting my photos. Okay, according to my daughter. And she's right. And is there anything that I can do to train my eye? Or do you have any suggestions from you? Right. Um, especially on the green casts on the green cast. Um, so I mean, training right. Comes with experience Just looking at a whole bunch of images. But you could also use tools and photoshopped that Let me turn something on here. Let me find something that will work here. Um, I really didn't talk much, but much about history, Grams. But maybe that could help you out. Um, so if you go into window hissed a gram, you're right. You're I mean, this is an obvious example, of course, But when you look at a history Graham, you could see that the Green Channel zoom answer that. You can see you could see where the information is. And if you have a color casts, usually you're going to see in the highlights, and it's gonna stand out. So here, you see how the green one is really sticking out. So it might be a way off of you knowing also. I mean, I guess we could fake it so that you could see if you go into I don't know, uh, curves Let me see how I could fake this. Um, yeah, so I now have a yellow color caste and you'll notice that there's no blue. So I mean, those are visual cues that you could see using the history Graham, if that helps, um, another way is, and I really didn't talk much about this. But another way of this is actually a good example for that. If you go into window an info and you can just hover over anything that you know in your head should be a neutral gray. So we know that this truck shouldn't have a clerk, has me know that if we hover over it, you can see the R G V values notice that the RGB values and what I'm looking at is right here. So I'm gonna zoom in, so that's what we'll be looking at. So when I'm hovering over there, you'll see that there's an arguably value of 101 1 79 and 1 13 For these to be neutral, they only to be more or less the same number. So right off the bat, just by looking at those values, I can see that the highest value is green 1 79 So I know there's a lot of green, and I know that I need to make him closer to each other. And I mean, just just by using the the eyedropper here and and, um, hovering over now if I zoom in, don't look at the same values. Now look at the before values that the values here on the right hand side notice not. There's 1 31 35 1 40 They're much closer to each other. So neutral grays will always have in the perfect world. And this is not gonna have never gonna happen the real world. But they're always gonna have the same value. Um, or in the real world, more likely a matter to be like that where they're very close to each other. And just to drive the point further, I can open up the color picker and look at the RGB values here Red, green and blue. If I click and drag down. Not is that the neutral grace always have the same value on all three channels because there is no more or no less of anyone color. That's how you get neutral colors. So that may help you looking at an image. And if you can't see it, just hover over it with your cursor and look at the RGB values and something may stick out, but within time, you should be able to notice it just by looking at it. What happens when you have, like, double dominance in a situation off color aluminum, right? You're shooting on. Happened to me in a church had a wooden ceiling and they wouldn't allow us to put like flashes. Right. So I had to bounce off, Would right? Everybody looked like just coming out of the beach and very orange. Yeah, but then the like, I could I could work with the white balance from camera to kind of light it up and because I'm having two different lines. But the problem was with the people behind, right? Because then I would have the the orange hue going into them that wouldn't match right. The people that I had in front illuminated by the flash. So So I think if I don't get it, please stop me, and I'll try to answer it. So the way that I would go Listen, we already have. You have one image that multiple images or like, I guess what I'm saying is that you were you trying to composite those together? Okay, so, just like so maybe you should have one shot. One shot out. What? What? What? Since this wedding thing is that I cannot really go and do rice garnished by image is like, Yeah, So, um, sort of like that example I showed earlier with the I mean, at least is the way I will tackle that. It's the, um oh, May headed hero that somebody example like this one, where earlier I showed you make selections and you just focus and target a specific area. So maybe the people in the front have the better colored stones or, you know, for lack of a better term of the ones for, you know, white balance. But then the people in the back are the ones that are not correct. Is Was that the problem? Some like that, at least some like that. Yeah. So what I would do is it will become a compositing job for me at that point. And what I mean by that is I could either. I probably wouldn't cropped them out in 20 later. What I probably would do is it's sort of like what I did in this example here, where I selected the that section that I want to focus on and then just make targeted color adjustments using layer mask. But essentially is a compositing job at that point, cause you're not, you're not doing the overall image or just doing the images that the sections that need that need color correction. Yeah, because obviously, if you color correct, one is gonna affect the other. Of course. So that's that's the way that I will tackle that.