Optimizing Grayscale with Levels
And now let's think about what would I do if I've already adjusted an image with Camera Raw, and then I need to do further adjustments. Well, there's a bunch of adjustments that we have available. Let's start talking about a black and white image. And let's say that this image, since it's an old picture, is one that wasn't taken with a camera directly, instead, this was a photographic print that was scanned. And therefore, I don't have a raw file available. Well, I'd like to show you how an adjustment known as levels works. And I'm gonna use two images to do so. We'll use this image, and I'll also use a simplified image, which is this, generically known as a gray wedge. And I'm gonna start by choosing image, adjustments. In here we have a bunch of adjustment choices. This image is in gray scale mode, that means that Photoshop knows it does not contain any color. If I come up here you'll see that it's in gray scale mode. And therefore, any adjustments that require color become grayed ou...
t. If I wanted to use any of those, I'd have to change the mode up here from gray scale, to RGB. Then everything would be available. But looking at the adjustments that do show up, let's just take a look at 'em. First we have brightness and contrast. With brightness and contrast, we just have two sliders. The brightness slider is gonna brighten or darken your picture, and the one thing that's nice about it is, watch what happens to the extremes of black and white. When I darken the image, notice the white remains white, and when I brighten the image, notice that black remains black. Then therefore, if you had the full brightness range to begin with, you're gonna still have the full brightness range from black to white when you're done. It's just everything that's in between those two, will be brightened or darkened. Then we have contrast, and contrast means, how big of a difference is there between bright-ish areas and darkish areas? So if you look at areas that are relatively bright, and areas that are relatively dark, if I increase contrast there'll be a greater difference between the two. And therefore, bright areas will get brighter, and dark areas will get even darker. Now there's a greater difference between bright and dark. If I reduce it, then instead the difference between bright and dark is gonna become more similar. And therefore, both the bright areas, and the dark areas, are gonna get closer to middle gray as I lower this. Well the problem with this, is it's always thinking about an image as if it has the full brightness range available. So if your image that you originally opened up was a picture of snow, and the snow had no real shadows to it to make a slightly shadowy areas, so that the entirety of the image went from white down to about this brightness level here. That's the darkest there was in the entire photograph. Well then, when I increase contrast, since it changes the relationship between bright-ish and darkish tones, increasing it is just gonna brighten that entire snow photograph because the entire image is in that bright range. And lowering contrast will just darken the entire snowy photograph. This doesn't allow me to really target things with precision. This is simply the simplest brightness or tonal adjustment. Now there is a checkbox called use legacy, there used to be a different version of brightness and contrast, one that was so basic, that you'd almost never use it. And if you want to use the old version, you can turn on use legacy. And in that case, if I adjust brightness, every single tone in the image is brightened an equal amount. So do you see what happens to black? And if I darken, every single tone in the image will be darkened an equal amount. So do you see what happens to white? And then with contrast, it's going to make bright areas brighter, dark areas darker, but it'll be very easy for areas to turn solid white or sold black. And if you bring it down, it'll be much easier to get to like, everything being identical. For a photographic image, that's not very effective. And that's what we used to have. If you went with Photoshop 1. up through Photoshop I don't remember what number, but many years. That's all we had for brightness and contrast. Now I mention that because, the use legacy checkbox is extremely useful. Just not when you're working on a photographic image. Instead, it's useful when you're working on a mask. You can have layer mask, we have a lesson about layer masks as part of the Ultimate Guide, and if I was working on that layer mask, I might wanna take the entirety of whatever happens to be there, and brighten or darken it. And this would be an effective way to do so. But you won't see me using brightness and contrast on any pictures, unless I'm teaching an absolute beginner in Photoshop, because they usually want more control. So, as you work your way down these top three choices, you get more and more control. So now let's go to levels, and see how it works. With levels, there are a total of five adjustment sliders to work with. If you stat with the upper right slider, it will force areas to white. As I bring it in towards the middle, more and more of my image will become solid white. But to truly understand the way it works, you need to pay attention to the gradient that's right down here, this ramp that goes from black to white. And you need to look at where that slider is, relative to that little bar. That bar shows you all the brightness levels you could possibly have in your picture. And as you move this slider to the left, and you go straight down here, anything that's to the right of the slider, in the bar at the bottom, is gonna turn white. And so, if I were to bring it in to that middle, that means, go straight down from it, anything that used to be this brightness level of my picture, and anything brighter than that, will be solid white. And everything that's darker than that, is gonna be brightened along with it. Actually, yeah, so watch this. If I bring this in you'll see more and more of the image becoming white, because all those shades that are turning white are found in this region right here. Then, it just keeps a consistent transition between all the other shades. So as I bring this up, now that this shade here is white, this one is just as different from it as it was before, and so it brightened up along with it. If I bring in the upper left slider, then it's gonna force areas to black. Anything to the left of it will turn black. And when I say left of it, I mean in the gradient at the bottom. And therefore, if I bring it half way in, everything that was 50% gray or darker becomes black. Now that can be very useful. Let's say you scan in your signature. And when you wrote in your signature, you used a pencil on a sheet of paper. And the paper was not vividly white, it wasn't extremely bright, instead there had a little tonality to it. So when you scan in your signature, the paper comes in as a shade of gray, and your signature comes in as a darker shade of gray, but what you want is solid white paper, and a solid black signature. Well, if you brought this in, you could, you could end up getting that paper eventually to turn white. Because it would be in this general brightness range. Then if your signature, let's say, was about this bright when you scanned it, because it was in pencil, you could bring this slider over until it's beyond it, and you'd force it to black. So it'd be a really nice way of working. The middle slider is going to force things to 50% gray. So that's why it starts out in the middle, because if you go straight down from it, that's where 50% gray is found originally. If I were to move it this direction, then what is right here, if I get it to be right above that, will end up being 50% gray. Well this used to be darker than 50% gray. So moving it this direction will brighten your image, making what is directly below it 50% gray. If I move it the opposite direction, then something over here is gonna become 50% gray. These were originally brighter than 50%, so when I get it over here it's gonna be darkening. Now that is very useful when you're working with textures. We have a session within the Ultimate Guide, that covers a feature known as blending modes. And in blending modes, there is one set of modes that makes 50% go away. And so, if you scanned in a texture, and you want the majority of the texture to go away, then you want the majority of the texture to be exactly 50% gray when using those modes. Well this middle slider right here, if you can get it pointing at the exact shade of what's in your texture, it can be very useful. So it's really good to know how these sliders work, 'cause it's not just when adjusting normal images that you're gonna be using this, it's also when you're applying textures, when you're working with masks, and all sorts of other things that you might wanna think about this. There's two more sliders, and their found down here at the bottom. The slider on the left, if I pull it in, is going to make what used to be white in our picture, it's gonna change it to the shade of gray this point's at. So, over here is white in this image, and if I were to pull this over to the left, we're no longer gonna have any white. Instead, the brightest part of our picture will be whatever this point's at. By bringing the opposite one, that controls how bright things are that used to be black. When you bring it in, now black will become whatever this point's at. There's a bunch of good reasons for using that. Let's say you print on a printer that you have on your desk. And you find out that every time you print, the dark part of your image, where you could see detail on screen, comes out as solid black. It's just, you're using cheap paper, and you're using ink to print with, and that ink is absorbing into the paper, and as it does, it spreads out as it absorbs in. And any variation there was, in an area that was 98% gray, or something like that, becomes solid black. Well, you can do a test, you could print an image similar to this. Although, you'd have it so all the shades are dark, so it's kinda like that, and then you could print it out and say what's the first one of these that actually looks different from black? And if you were to figure out how bright that shade was, then when you're about to prepare an image to print on your printer, you can just take this slider and point it right at that shade. The darkest shade where you can still see a hint of detail. So that should give you an idea of what these sliders do. Let's use them now to adjust an image.