Refining tonality with Levels
Video: Refining tonality with LevelsIn many cases, the Brightness/Contrast adjustment is all you really need in adjusting the overall exposure for a photo. But if you are a control freak like me, you might want to exercise a bit more control especially over the contrast portion of that Brightness/Contrast adjustment. For that we can use levels. I'll go ahead and get started by adding a levels adjustment layer, so that we can see what sort of controls are available there. At the bottom of the Layers panel, I'll click on the Add New Adjustment Layer button. And then, on the popup I'll choose Levels.
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The core strength of Adobe Photoshop is the way it enables you to improve the quality of your images, whether you're fixing a major problem or making a subtle adjustment. In this workshop Tim Grey explores a wide variety of techniques to help you get the best results when optimizing your images. He begins with basics like cropping, changing brightness and contrast, and correcting color balance, then moves on to more advanced adjustments like Shadows/Highlights, Curves, and dodging and burning. Then learn how to make targeted adjustments that affect only selected parts of the image and apply creative adjustments that don't so much fix a problem as add a unique touch. And best of all, Tim teaches all these techniques as part of an overall workflow designed to help you work quickly, efficiently, and nondestructively.
- Configuring the Photoshop interface
- Opening an existing image
- Basic RAW conversion
- Introduction to adjustment layers
- Reviewing adjustments
- Saving the master image
- Basic, advanced, and creative adjustments
Refining tonality with Levels
In many cases, the Brightness/Contrast adjustment is all you really need in adjusting the overall exposure for a photo. But if you are a control freak like me, you might want to exercise a bit more control especially over the contrast portion of that Brightness/Contrast adjustment. For that we can use levels. I'll go ahead and get started by adding a levels adjustment layer, so that we can see what sort of controls are available there. At the bottom of the Layers panel, I'll click on the Add New Adjustment Layer button. And then, on the popup I'll choose Levels.
In the Properties panel you can see quite a lot of adjustments here, quite a number of controls that we might want to take a look at. But for our basic overall tonal adjustment, we actually only need to touch three of these controls. Those are the white point adjustment the black point adjustment or the middle tone or gamma value. The white point will determine the value of white. In other words what tonal value should be increased in brightness, so that it equals white? For illustrative purposes, lets make a dramatic adjustment here. If I move that slider to about the mid-tone value, then any pixel that had a imminence, brightness value of around middle gray, will be made white. Obviously, that doesn't produce a great result in this image and it probably wouldn't produce a great result in any image.
But it gives you a sense of how the white point adjustment works. The way I typically approach the white point adjustment, is to set it to around about the point where the data first appears on the bright end of the scale with the histogram. Of course, if you want to get a little bit more detailed, you can also use the Clipping Preview display. I'll hold the Alt key on Windows or the Option key on Macintosh, while adjusting that white point slider. And as I drag the slider to the left, we'll start to see pixels appearing. Those pixels indicate which channel or channels are being clipped, in other words are losing detail.
The color indicates which channel is losing information and a white value indicates that that area has become literally pure white. So, the general practice would be to hold the Alt or Option key and drag the slider to left until you start to see pixels appearing. And then take that white point slider back over to the right, until the point where the last of those pixels disappears. I'll then release the mouse. I can let go of the Alt or Option key. And we'll take a look at the actual result within the image. I'll turn off the visibility of my adjustment, so that we can see the before and after. So, here's the before, there's the after.
We've just brightened up the brightest pixels a little bit. So, not a huge adjustment, but one that will help optimize the overall appearance of the photo. I can perform a similar adjustment with my black point slider. And this, similarly, will determine which pixel values are going to mapped to black. So, if I drag that slider over to the right, you'll see that more and more pixels are being made black in the image. Once again, I can use that clip and preview. So, I'll hold the Alt key on Windows or the Option key on Macintosh. Any pixels that appear here that are not white are an indication of lost detail in the shadows, for one or more channels. And just as we saw for the white point slider, I'll generally back this off to the point where all of those pixels disappear.
In some cases, including with this image, moving all the way over to the left will still not cause all the pickles to disappear. And that's an indication that in the original capture, a little bit of detail was lost in those shadows. Here it's just a handful of pickles, so not a problem at all. I'll release the Alt or Option key and I'll continue fine tuning this adjustment. I think I would like a little bit more density in those dark shadow areas. I can always hold the Alt or Option key again in order to check that clipping. And that looks to be a good result. So, that has established the overall contrast.
Now the reason this is better than using the Contrast slider in the Brightness/Contrast adjustment, is that we're able to adjust the white point and the black point individually. With Brightness/Contrast, both are being adjusted by Photoshop automatically behind the scenes. We don't have any control over that process. The final adjustment that we want to take a look at here is the mid term slider and this is in effect just a brightness adjustment. If we move the slider to right, then more of the pixel values will fall to the darker side of middle gray. If we move the slider to the left then all those pixel values will fall to the brighter side of middle gray.
And so, we can simply fine tune as we see fit. With this mid tone adjustment, we don't have the benefit of a clipping preview because we're not adjusting the black point or the white point. So, there isn't going to be any additional clipping. So, this is purely based on a visual evaluation of the image. Generally speaking, I would say that I tend to favor a slightly darker version of the image. That's not to suggest that the image should be made to be too dark. It just means that the image tends to look a little bit better if there's good density in it, if there's good dark values.
For this image, that doesn't require much of an adjustment at all. I'll take that slider over to the right to from its starting point just a little bit. One of the side benefits, by the way, of slightly darkening the image is that the colors will look a little bit more vibrant. They will have a little bit more saturation to them because they don't have that washed out appearance. In terms of making a basic brightness and contrast adjustment, basically your overall exposure adjustment using Levels. Those are the only controls you need to concern yourself with. We establish the white point, the black point, and the mid tone value.
We don't need to worry about the output levels in most cases. Moving the black point inward will brighten the value of black, moving the white point inward will darken the value of white, and in most cases we don't want to do that. And when tonal adjustments are our focus we'll only be working with the RGB option. We could work with the individual color channels to affect a color change in the image. But for our overall exposure adjustment, that brightness contrast adjustment will only need to work in the RGB adjustment. So, as you can see, while the Levels adjustment might look a little bit complicated at first glance.
It's actually relatively simple to use and it gives us a little bit higher degree of control than Brightness/Contrast. And so, I think, you just might find that this is your go to tool for adjusting the overall brightness and contrast in your images.
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