Essential Color Correction Concepts in Photoshop


Advanced Color Correction in Photoshop


Lesson Info

Essential Color Correction Concepts in Photoshop

The first essential thing is to know that your images in general are made out of red, green and blue light behind the scenes in Photoshop. And the more you know about how red, green and blue light works, the more effective you can be. And if you're, have been around for a while, you're not you know, really young, instead you've been around where, you remember when big TVs, projection TVs, used to look like this? This one I captured on a plane, like decades ago. Where in order to make the image that was being projected, it was using red, green and blue light, and it's easy to see that, you can even put your hand in front of it and see it changing the colors of what's coming out, so it doesn't look right. But behind the scenes in Photoshop, it's the same thing. It makes your image out of red, green and blue. So let's learn a bit about red, green and blue. Here is one essential concept when it comes to color correction. Imagine this is just a dark room. And I have a flashlight that puts o...

ut red light, another one that puts out green, and another one that puts out blue. And if I come in here and make one flashlight, move it around and have it overlap another, when green and red are combined together, we see whatever color you get when they combine together, which happens to be yellow. If we take blue over here and bring it over there as well, so we get all three colors of light in the same spot, we get white light. And so any time you see white on your TV screen or anything like that, it's just using an equal amount of red, green and blue. So then if we look at that a little bit further, here instead of just having one shade of red, green and blue, I've varied how bright it is. And let's see what happens if I get these to precisely overlap each other. So you notice that whenever red, green and blue is balanced where we have the exact same amount of red that we do have green, that we do have blue. What you have is a shade of gray. Now if we were to vary that, we wouldn't have shades of gray. We'd have colors instead. But if you can remember that balanced red, green and blue equals gray, that's the first essential concept to understand when it comes to doing color correction. You might not know why yet, 'cause you're like well who cares about gray? I wanna fix the colors in my picture. Well we can do that easily. What we want to do is when you get an image like this RAW file I'll open. In order to figure out what's wrong with the colors, we're gonna look for areas that should be gray. And when I talk about gray, I mean any brightness level of gray. When I just say gray, a lot of people think of a particular gray. No, this is anything that would be in a gray scale photograph. A black and white picture. From black to white or anything in between, OK? So in this particular case, this is a photo of an old gas station. And I know that this particular type of old gas station ah this area here is painted white. I mean when I was standin' there taking the photo it was pretty obvious that it was white. Well if I'm here in Camera RAW, over on the right side, do you see where it says R G B? That will tell me when I move my mouse on top of the image how much red, green and blue makes up the area of the image I move my mouse on to. So if I know that this station is painted white, white is a shade of gray, then the formula for creating that color when it's accurately portrayed is a balanced amount of red, green and blue. Remember that from when I was showing you the thing. So let's find out, let's say we were colorblind totally, could I find out if this building is truly white in the photo or not? Well if I move my mouse onto this area right here, and I'll zoom up so you can see the readouts over here, where it says R G B, and you notice they're not balanced. If they were exactly the same numbers for red, green and blue, then this would be a shade of gray, where my mouse is, but it's not. So the simplest control we have for color correction is here in Camera RAW, and it's one of the best places to do color correction, if it's a RAW file. And that is this little eyedropper right here is the white balance eyedropper, and watch what happens when I put my mouse on top of the image and I click. You don't even have to look at the image yet, just watch the numbers where it says R G B. Now they didn't become exactly equal, but they became really, really close. If you're within about three on that number scale, it's close enough, alright? But do you notice that that's all I did. What it did is it looked at the area that I had my mouse on top of, it assumed that it should be gray there, and it just looked at the numbers that were sitting there. And it said what would I have to do to these numbers to get 'em to be equal? So imagine you just added those three numbers together and you divide it by three. Wouldn't that be like the average, of whatever the numbers are? And you could try to get 'em all set to that. And if so, you would be doing what the white balance eyedropper is doing. But the key concept, see there, they're almost perfectly equal, is that we're gonna figure out what color is contaminating this picture and how strong is that color by looking at an area that shouldn't have any color. And those numbers, the further they are off from being balanced, the more of a color there is in there. And it can calculate exactly how it needs to be changed. All it's doin' is averaging those three numbers and somehow adjusting the image to get there. So I can click here. And your eyes can be messed with. And whenever you color correct an image, it's best that you look away from the image for at least a few seconds and look back before you really evaluate the end results. And I'm not certain if I have it readily available here, just take me a second to look, ahhhhhhh. No, I don't. But um there is a little trick you might have seen before, here it is. I knew I had it somewhere. If you come in here and, what I'm going to do is, I'm gonna choose a shade of gray and in a moment, I'm gonna replace this flag with a shade of gray. But before I do, let's zoom up on it, and let's just see how and why you wanna look away from your screen after you do color correction, and then look back. So look at this flag and stare at the black circle that's in the middle. If you stare at the black circle and try not to look away from it, it'd be better if you were close to the screen where you can get it to fill your vision, but what's happening is, the longer you look at this image, the more your eyes are getting used to it. And your eyes automatically color correct the scenes you walk through. You walk under fluorescent lights and your eyes adjust to make everything look as if it was under white light. That type of thing. But as it adjusts like that, it can mess things up. Because right now if you're staring at that black circle and I replace it with something else, like gray, can anybody happen to still see any colors there? You can still see a flag? In fact you usually see the opposite colors. And so what happens though, when you're color correcting something, as I was doing with that previous image, this one, is the moment I clicked on it, and it made the surface that I clicked on so it was a shade of gray, it will look like instead you see the opposite of what used to be there. And it's the same thing as staring at that flag. You're staring at the image so long, your eyes are getting used to it and you actually see less and less of the color cast as your eye adjusts to it. The moment you get rid of it, then you've overcompensated and you suddenly see the opposite. So whenever you do color correction, when you think you're done, look away, look at other things for a while, and then come back to it, OK? So that's one essential concept, which was a balanced amount of red, green and blue makes gray. The second concept being, we're gonna look for grays within our picture and we're gonna use it to measure how strong a color cast is, and what color it happens to be. The computer will do that for us. Using either the white balance eyedropper or had I not used it here, let me um, just reset my, reset this. If I hit open image, an equivalent eyedropper in Photoshop itself instead of in Camera RAW would be if I were to come in here to either Levels or Curves, it doesn't matter which one, there is a set of three eyedroppers over here on the right side, and the middle one is the one that doesn't care what, how bright things are when you click on things. And if I clicked right here, it would try to do a similar thing. Now did you notice it's nowhere near as good? And that's why it's better to do it in Camera RAW. It's better to do it before we get into all the way into Photoshop. It will be able to do a better job. Now there are other eyedroppers in there that can help me and also there's one thing that could be messed up. I can actually change what those eyedroppers are set to. I wanna double check really quick that they're at their defaults, 'cause who knows when you start a seminar? And they are, OK. So it's best -- we're gonna get the highest quality if we do it in Camera RAW, so we wanna start off there. Then let's think about other essential concepts. And that is if we just look at any image, just pick anything you wanna think about. In fact, let's just look for a normal um, photograph possibly. We'll look at this one. If you look at the absolute darkest part of a photograph. In the vast majority of cases, you will find that the absolute darkest part of the photo unless it looks like a foggy image, where it doesn't have much contrast, looks all washed out or something, you'll find that there's no color in the darkest part of the image. Do you notice that here? If you try to search for the darkest area. It's because even though there's a red door there, and it might be near the top of the red door where it's the darkest area, you can't see any color in it. And that happens because in order to have color you can't be close to solid black or solid white. At the extremes of the brightness range, you can't have color. In order to have the color, you just can't be within those limits of the brightness. So also look at the absolute brightest part of the image. And you'll notice that there's usually no color in the absolute brightest part. Here it might be obvious, because there's a white box on the wall near the top, but even if you were to crop that out and then look for the brightest, it might be the edge of this little thing here, whatever it's the doorbell or something that's there, but usually the brightest area of most photos even if it's a picture of a bright red apple, look at the brightest area and it'll usually have no color in it. With a few exceptions. And so we can use that as a concept that can help us do color correction. So that if we wanna color correct an image, I can come in here and there are some eyedroppers that you find in either Levels or Curves, it doesn't matter which of the two you use. 'Cause the eyedroppers are identical. They're right over here. With all three of these eyedroppers, it's going to try to give us a balanced amount of red, green and blue wherever we click. The only difference is, this one when you click on it, if you look it's full of white, is gonna make things as bright as they can be at the same time. This one'll make things as dark as they can be. And this one'll try to leave the brightness the way it was. So what that means is I can come in here and sure with that middle eyedropper I could attempt to look in the photograph for something that should be a shade of gray, maybe it's this metallic area here, click and see if it improves the picture, or there's a sign here that's probably painted white, click there and it'll improve the image. But if I do it with only one of those eyedroppers, it won't be as precise as using all three. If you use all three, then we have three different areas. The bright area, a dark area, and a middle area, to calculate what the change we need to make. It'll be more precise. I'm gonna reset this, watch the Cancel button. If you hold on Option, it changes to Reset. And that's Alt in Windows. And just to start over, I'm gonna start with the white eyedropper. And I'm gonna click on where I think the brightest part of the image is. And I'm somewhat guessing at where the brightest part is. There are techniques for figuring out precisely, but for now we're just looking at it conceptually. I'll grab the black eyedropper, and I believe the darkest area is somewhere in these trees. And then I'll grab the middle eyedropper and I always do the middle one last. If I'm doing the three eyedroppers, and I'm just looking for something I'd recognize that I think would be white or a shade of gray if I were to walk into the scene and experience it, and I would say the background on this handicapped parking sign, or this white sign here. The painted handicapped thing on the driveway, although being driven over enough times it could be kinda brownish, or sometimes if it's metal, as long as it's a matte finish metal, like a brushed finish and not a chrome, shiny finish. A chrome finish is just gonna reflect like a mirror everything around it, so it's not necessarily a great spot. And what I can do with the middle eyedropper is just click and see if it improves the image and just experiment with different areas. I'll try the sign, I'll try the other sign, and I'll go with whichever one makes the image look its best. And if you wanna see before and after, here I'll turn Preview off. There's before, here's after. And after that you're welcome to go in and make any kind of brightness adjustment you'd like, ah so I'm not trying to fix how bright the windows are or anything like that, I'm trying to just do color correction. I could always come in here afterwards and I like Curves, a lot of people aren't comfortable with Curves, but I like 'em. And could come in here and say, let's lock in the brightness of this and brighten this up. And if I had a, if I mask that I could make it so it doesn't affect the sky, that kind of thing. But you get the idea that the eyedroppers are basically the same concepts as a balanced amount of red, green and blue makes gray. We're looking for gray things because it's the easy way to measure what is contaminating this picture to make it look like it has a color cast. And the brightest and darkest areas usually in order to truly be really bright and really dark, they contain no color. If you are not used to that concept, I'll click on my foreground color. And I'm gonna choose the most vivid red I can get. And then there's a setting here for B, which is the brightness. I'll click on it and I'll use my down arrow key to darken red. And if you just watch, this right here is the end result. And I'm gonna darken red, and just watch what happens to the amount of color that's in it as I darken it. And once I get down, here's -- we're at 10%, we're still not black yet, but do you notice that you can barely see any color at all? And once you get to the extreme of either no color or really close to it, there is next to nothing in there. And it doesn't matter what color you start with. If you start with blue or green or red or anything else, darken it up to almost black, and the color has to disappear in order to get that dark. And so you can kinda cheat, by working on the brightest and darkest parts of the image.

Class Description

Master the art of color correction, and learn how to edit images with challenging lighting issues. Make use of the wide variety of features that Photoshop has available for images with mixed light sources, complex highlight and shadow situations, or underwater lighting. Gain the ability to bring images that you believe to be terrible back from the brink of the trashcan, and shoot with greater confidence that you can correct your images in post.  

Software Used: Adobe Photoshop CC 2015.1.2


Rachelle R. Vetter

Great course w a lot of good information.

Carolyn Whiteside

Awesome explanation of color and how to use that knowledge to apply to color correcting techniques!