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Curves for Color

Lesson 2 from: Color Adjustments in Adobe Photoshop

Ben Willmore

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Lesson Info

2. Curves for Color

Lesson Info

Curves for Color

All right. Now, let's take a look at some examples of warm cool adjustments. The one that I use the most is called Curves. And that's because Curves offers you the most control over what you're doing. In fact, most all of the other warm cool adjustments are really using Curves behind the scenes and they're just not giving you all the power that Curves could use. Instead, they're trying to simplify what is presented. Like when using Color Balance. But we could do everything that Color Balance can do and just do it right here in Curves. Anytime you see me use Curves, you're gonna find that this set of icon that looks like a hand is always turned on. It's got a dark background that indicates it's turned on. And that's because I've gone to the upper right where there's a little menu in Curves. and there's a choice called Auto-Select Targeted Adjustment Tool. And I have that turned on and I'd suggest you turn it on. What that does is it makes it so every single time you access Curves, that ...

little hand icon will be turned on. If the hand is not turned on, then if you move your mouse onto your image, you'll be using whatever tool you last used in your Tools panel, like the Paintbrush tool or the hand tool or whatever it was. But if that hand icon's turned on when you move your mouse on top of your picture, it's gonna think about Curves. And that's what I need it to do. So let's take a brief look at Curves. In Curves, if this menu is set to RGB, then I'm gonna try to be just making brightness changes to my picture. And that's true not just to Curves, but any adjustment that has the choice of RGB and then, individually red, green and blue. That means things like Levels, offers the same control and it'll work the same way. So if that sets at RGB and I click on my picture, I'm gonna try to darken or brighten the picture. But the colors shouldn't shift around. If on the other hand, I change that menu to red, now, I'm only controlling the amount of red light that the images made out of. So if I click within my picture and I push up, I'm gonna brighten my picture cause we're adding light, but I'm adding red light so it should become more red. If I end up switching it to green and I move it up, I'm gonna make it brighter and use green light to do that with. so it becomes more green. If I switch it to blue and move it up, it's gonna make it brighter and we're using blue light so it becomes more blue. But those same three colors have opposites. So if I use less red, it's as if I use the opposite color of red to absorb it. The opposite of red, if I look in my Info panel is cyan. So if I move this down, I'm using less and less red and that's really making more and more of its opposite appear, which is cyan. I come here to green. Oops, If I get to the red color. I look in the Info panel to see what the opposite of green is, magenta. So when I pull this down to use less green, it becomes more of the opposite. Can't even see the dot in there to get rid of it. And then blue. The opposite of blue if you look in the Info panel is yellow. And so if I click here and move down, less blue really means more yellow. So any adjustment that offers a pop up menu that defaults the RGB but when you click on it, it has a choice of red, green, and blue, those are warm, cool adjustments. Moving something one way will make things warmer, moving into the opposite way will make it cooler. So, that's one type of adjustment. That type of adjustment is useful when you have a picture that has a colorcast. Like this one. That image to me looks like it has too much blue and maybe too much green. And if so, I wanna use a warm cool adjustment and I want to see if I can lessen the amount of each of those colors. So here I'll do a Curves adjustment layer. And let's say I think there's too much blue in there. So I set this to blue, I move my mouse on top of the image to an area where it looks like it has an excess of blue and I drag down. Down. And once I do, I notice that now the image feels like it has an excess of green. That means it really had an excess of both. So, I can set this to green. Now you click on an area that looks to be too green and I could drag it down. And if I was able to do that, I might be able to get this image to look better. Might need a little less blue as well. But right now, I'm just trusting my screen, my eyes and just my guessing as to what color I think I'm seeing too much of. There is a way to get Photoshop to figure it out for us. I'm gonna throw away this adjustment layer and let's see what we can do. Well, there's a general concept that can be helpful. Let's take a look at it by clicking on my foreground color and getting to the color picker. If I pick a color in here, you'll find the numbers on the right side changing. Those are formulas for how you could describe the color that I currently have. So to describe this particular green color, I could get on the phone with somebody. And if I just said it's vivid green, do you think they'd be able to know what color I'm looking at? Probably not. They'll have some idea the category it would be in, but not the exact color. If on the other hand, I told them to click on their foreground color. So they saw the same screen. And I told them to type in any one of these sets of numbers. Either the three numbers that make up HSB, the three numbers that make RGB or the three numbers that make up LAB or the four for CMYK, they'd be able to see the same color. Although I shouldn't quite say that cause it's not true for CMYK. This color is too vivid to be described with that. But, it's a precise way of describing a color. The numbers don't usually mean anything to you necessarily unless you've used them for decades. But they're very useful. So, let's learn just a little bit about those numbers In sense, we're gonna be working with adjustments, they'll offer the choices of red, green and blue. We're gonna look at those numbers, RGB numbers. So, what I'm gonna do here is I'm gonna choose a shade of gray. Over here on the left side, these are all shades of gray. And when I choose these different shades of gray, keep an eye at the numbers that'll show up on the right side of my screen, just the RGB numbers and see if you can learn anything about them. Here I'll choose a dark shade of gray, I'll choose a medium shade of gray, I'll choose a bright shade of gray. And you should learn something about it because you'll notice that all of the shades of gray have a balanced amount of red, green and blue. Red, green and blue are exactly the same. If they're ever not exactly the same, then it's not a shade of gray. So if I choose any color, it doesn't matter how mellow the color is. When you look at the RGB numbers, you find that they vary. So when red, green, and blue are in perfect balance, you have a shade of gray. Whenever they get out of balance, you have a color. If red is above the others, it's a reddish color. Green is above the others, you have a greenish color and so on. If you just knew that, then there'd be a chance you could figure out how to color correct a picture. The key to color correcting a picture is to find areas that should be a shade of gray. And then looking at them with those numbers to see if they're balanced. And if they're not balanced, it's not a shade of gray. And therefore you have an excess of some color that shouldn't be there. And that's what a colorcast is. So, here I have a coffee mug which is a white mug. So, as long as there's not a coffee stain on the outside of it, where it would be brownish. If I were to take a picture that included this mug and I move my mouse on top of it, I could look in the info panel and it would tell me exactly how much red, green and blue is in the mug. And if it wasn't balanced, then there would be too much of some color in the image. Whatever color is above the average, that's there. Same with these little dongles that connect my computer to various cables. They're white. That's a shade of gray. Shouldn't have any color in them. Same with the metal that's around this screen that's near me. It's made out of aluminum and it's gray. I don't think it's reddish or bluish or any other color, and therefore, those numbers should be equal. Well, what happens is as you take any color and you take it to its extreme of brightness, if you look in a color picker and let's say you look at red. You're thinking about a red apple for instance. If you look at the brightest highlight on a red apple, it's not red. Even if it's a really vividly red apple in every inch of the apple. Because what happens is in order to be extremely bright, you just can't have any color. So the next time you look at a vividly colored object, especially if it's a shiny one, look at where the highlight is. Where the light is hitting it the brightest. And you'll find that the color in general usually goes away And you won't be able to just think of this. You've gotta look at photos. The next time you're watching TV and somebody sets an apple on the table, watch the highlight. There won't be any coloring, most of the time. The same is true for the dark portion of an object. If it's a red apple and you take a picture of it, look at the absolute darkest part of the red apple, and there won't be any color showing up. And that's simply because you can't have both an extremely dark area and color at the same time. So what that means is there are two special areas in a photograph that would usually contain no color. And that would be the extremes of brightness, the brightest in the darkest areas. And if we go into either Levels or Curves, you're gonna find little eyedroppers over on the side. Do you see them right here? One of them would be full of black, one of whom would be full of white and one is full of gray. They can be used for color correction. What they're designed to be used for is you grab the white one, you go into your image and you find the absolute brightest area that is not what's known as a specular highlight. A specular highlight is an area that has absolutely no detail. It's usually the light source itself or a reflection of that light source on something shiny. And so you avoid those. You're looking for what they call a diffused highlight which is just where it's not blown out to solid white. Anyway, I believe that that spot would be approximately here in this image. So, I'm gonna click there with the white eyedropper. Then I'm gonna grab the black eyedropper and I'm gonna think about where I think the darkest portion of this image is. The absolute darkest little speck in the image. And I'm gonna guesstimate it to be right here. And I'll click there. Then I'm gonna grab the middle eyedropper and I'm gonna look for something in the scene that I think should be gray. That means an object I might recognize would be gray. These columns might've been gray. And if so, I'm gonna click on it. Now, did you see what it just did when I did those three eyedroppers? Well, what three eyedroppers are doing, are using the concept of a balanced amount of red, green and blue makes gray. And what I'm doing is looking through the scene to find areas that I think should be gray. And usually by default you can use the brightest area of your picture for one and the darkest area for another because in order to be in extreme of brightness, you just can't outcolor there. And then it's mainly the middle one where I'm experimenting. Where if I had a coffee mug on my table, I'd be clicking on it because it's a white mug. Or if I had these little dongles or I've had my laptop that's silver color. It's not bluish or yellowish or anything. That's what I would use. Now there's a way to find the brightest and darkest parts of our images. So we don't have to guess. In this case I was guessing, so I'm gonna throw away this adjustment layer. Then I'll show you how you could do it without guessing. I'll go back into Curves. And in Curves, there are little sliders at the bottom. Those sliders do the same thing as the top outer sliders in Levels. If you happen to know how Levels works. And with those sliders, if you hold down the option key, which I have held down right now, and you pull this slider towards the middle until you see the first part of your image that actually turns white. Not blue, not yellow, not some other color, but white. It's showing you where the brightest part of your picture is. So right now I can see a whitish blob near the lower right and if I let go my mouse, I'm just gonna stare at it so I can recognize where it is. Okay. It's exactly where I was clicking. Then I'll bring that slider all the way back to its original position and I'm gonna do the same thing for the opposite slider. Hold down the Option key, which is Alt in Windows, click on it and then drag it towards the middle. And this time I'm dragging it till I see the first spot that turns solid black. And to me it looks like it's on the left side of my wife's hair. I see an area turning black. I'll let go just so I can stare at it and notice where it is. It was right over in here. Then I move this slider back to where it started. So these are at their extremes. Now that tells me where I could click with the white eyedropper, where I can click with the black eyedropper and where the middle one, it's not gonna tell me. I have to look around the scene and I'm looking for things I recognize that might be a shade of gray. And so, I'm don't remember, was my wife's outfit here gray or was it purple-ish? Or some other color? If I think there's a possibility it would be gray. I can click on it with the middle eyedropper. If the color improves, it was near gray. But then I can experiment and click on another area. Like what's up here. If I think those might have been gray and just move around until I've tried all the various areas that I think are possibilities of being gray and I end up going back to whatever one gave me the best color. So let's just say it was there. So I'll turn this off and back on again. You see how we can color correct picture. Well. What if we can get Photoshop to do that for us? Well, I'm gonna throw away this adjustment layer and start with a fresh one. And if I go to the side menu in Curves, there's a choice in here called Auto Options. And we can set up how the button called Auto, which is found in Curves works. And if I choose this, we have many different choices we can use. One is called find dark and light colors. That means use the same thing we just used a moment ago to find the brightest and darkest areas. Then it's gonna click on it with the black and white eyedroppers for us. There is a check box here called Snap Neutral Midtons. What that's going to do is it's gonna look through the scene for the area that's closest to having a balanced amount of red, green and blue and it's gonna assume that it should be exactly balanced. Which means it's gonna try to find something close to gray and click on it. It's not gonna be anywhere near as good as we could be. And then if I turn on this checkbox to save as defaults, then it's gonna remember all these settings. I click Okay and now in the future, if I ever want to color correct a picture, first off, I would usually do it in Adobe Camera Raw with the white balance adjustment. We talked about that in a lesson that was specific to Adobe Camera Raw. But here we're looking at our options in Photoshop. So imagine this was a scanned picture instead of one from a digital camera. But now that I've set that up, all I need to do is hit the auto button here and it will attempt to color correct my picture. And afterwards, I can always grab the middle eyedropper and experiment. You can just try other places in case it didn't do a great job of picking the best area. And I just click on any object that looks like it should be a shade of gray, shouldn't have any color in it. And I keep going until I find whichever area gives me the most pleasing color.

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Karen K Hafenstein

I have 120 years of teachers in my family. I have seen a lot of natural teachers and Ben Willmore is one of the best. The preparation he does for his classes is amazing. His dialogue throughout hits every detail and shows his prowess as an instructor. Thank you, Ben!! I always loved Photoshop but now I actually understand it!

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