From the course: Photoshop 2024 Essential Training

Adjusting color and tone with Levels and Curves - Photoshop Tutorial

From the course: Photoshop 2024 Essential Training

Start my 1-month free trial

Adjusting color and tone with Levels and Curves

“

- [Narrator] Two of the most powerful adjustment layers for changing tone and color are levels and curves. We'll start by making a global adjustment to extend the dynamic range of this photo using levels. Then we'll change the mid tones, color and make selective adjustments using curves. I'm going to use the adjustments panel in order to add a new levels adjustment layer. We can see that it shows a histogram on the properties panel. Now a histogram is just a visual representation of all of the values in your image, and it plots those values from black on the left to white on the right, and the height of the histogram is showing us how many values in the image are at that exact spot on the histogram, there are no right or wrong histograms, although if your histogram is showing a lot of values up against the left hand side or the right hand side of the histogram, then possibly in your image you have clipped images that are white to pure white with no detail, or you've clipped them to pure black with no detail. But this image actually has the opposite problem. So it is a flat image. It doesn't really have a black, there's no values between this area here and the black point, nor are there any values between this brightest area and the white point. So in order to adjust that, well, we could click the auto button, but I'm not too happy with those results. So I'm going to use command Z or control Z to undo that. And instead I'm going to manually move this over so that I have more control. So I'm going to click and drag over to set my black point. Now, if I hold down the option key while I drag, Photoshop is going to show me an overlay of the channels that are being clipped to pure black without detail. So the red and the yellow areas, that means there's only one or two channels clipped. It's the black areas where it's actually clipped with all three channels. So I could back off on this until I don't see any black. And then I'll do the same thing using the white point. I'll hold down the option or the alt key and drag this over until I see white in my image. That tells me that all three channels have been pushed to pure white or white without detail. So I'll just back off on that a bit. If you want to push your blacks to pure black, that's really an aesthetic call. There are plenty of photographers that have beautiful rich blacks without detail, but it's a little bit more difficult to push your whites to pure white because white without detail, especially if it's in a highlight like a cloud and you print it, it's really going to show up and your eye is going to be able to tell the difference between where there's information and where there's not. Now, when we make these kinds of adjustments, we can see the results in the histogram panel. If your histogram panel isn't showing, you can go under window and then choose histogram. And you'll notice that there's a warning here. If we click on that, it will re-render it because it was rendering the histogram using just a cached file. Because we're working with eight bit, we can see that by stretching out the dynamic range, we're actually causing some gaps in our histogram. And if these gaps get too big, then we might see some banding in our image. So that's why it's always best to work with 16 bit. But again, the demo files for this class are in eight bit. All right, if I want to change the mid tones using the levels adjustment layer, we have this one slider here. I can move it to the left or I can move it to the right. This is the gamma or the midpoint of our image, but we don't have a lot of controls. We only have this one slider. So for more controls, I'm going to hide this levels adjustment layer for a moment. And we're going to add a curves adjustment layer because a curves adjustment layer can have up to 16 different points on the curve, not just that one in the center. So again, we have the histogram showing here, and we do have the auto option, but we can also set the black and white point just like we did with levels by dragging over the black tick mark there and dragging over the white tick mark. And again, we could hold down the option or the alt key if we wanted to see a preview of our clipped areas in the image. We can either click in order to add a point on the curve or there are onscreen controls. So we can select this icon and then click and drag down to lower the curve or darken the value or click and drag up to lighten it. If I want to get rid of a point on a curve, as long as it's targeted, meaning we see that that square is filled in, we can just tap the delete key. All right, let's add an S-curve to this, meaning that I'm going to pull my shadows down a bit and I'm going to increase my highlights. So that's a good way to add contrast. But in this image, I think that it is adding too much contrast to the skull. So instead of pulling up my whites, I'm going to leave them alone and then just pull up my midtones a little bit. You have to be careful when you're using the curve because there are only so many values in your image. And if you make a change to the slope of the curve, like I increase the slope in one area, it's going to decrease the slope in another. And when it does that, it's going to flatten out a part of the curve. And when you look at your image, you'll notice those flat areas in the image. All right, so let's just pull back on there a little bit, and we can use the eye icon to toggle the before and after. We can also use the curve adjustment layer to change colors by going into the individual red, green, and blue channels. We can use these to either correct the color in an image or add a creative color effect. So in this case, if I move over the blue slider, we'll notice that we're getting a lot of yellows in our shadows. I don't necessarily want them in the midtone, so I might put another point on the curve there. And one more up here just to make sure that I don't get blue in the highlights. We can also go into the green or the reds and make adjustments here as well. Our adjustment layers can be applied to the entire document, or they can be applied to a selective area of the image. I'll choose my object selection tool and select the object finder. And then I'm going to click on top of the skull and we'll add another adjustment layer. I'll return to curves and I want to decrease the highlights a bit to bring back a little bit of detail, but then I don't want my shadow and midtone to go too dark, so I'll drag up on the curve there. Again, we can toggle the visibility. So that's before, and that's after. When you make a large adjustment to the curve, like we did right here, you might notice a little bit of a color shift. So we can always change the blend mode for the adjustment layer. And in this case, I'm going to change it down to luminosity so that it only affects the luminosity values and doesn't change the color. I did notice that the Object selection tool also selected this small area in here, so I could tap the B key to select the brush tool and then just zoom in and making sure that I've got black as my foreground color and the mask targeted in the layers panel. I can just paint that out of here. All right, let's zoom back out. And I noticed that this side right around here is a little bit lighter. I'd like to darken that down. So I'm going to tap the L key to select the lasso tool. And then I'm just going to make a rough selection right along here. Then I'll add another curves adjustment layer. And because I had a selection, it automatically converts the selection into a mask. I'm just going to bring the curve down a little bit, but we can see that line between what's been adjusted and what hasn't. So I'm going to click on the mask icon on the properties panel and just increase the feather, which will soften the edge of that mask, non-destructively. And of course, if I save this as a PSD file or as a TIFF file, I can open it in the future and make additional adjustments on any of these adjustment layers.

Contents