Tones, Contrast and Color
One of the cornerstones of Photoshop is its ability to correct the tonal properties of images. In this example we'll show you a couple of different methods of adjusting an image. There are many ways to adjust an image in Photoshop, and no one way is the correct way. Adobe simply presents a variety of methods to try. Some methods may work well in one particular situation, and other methods might work on other types of photos.
Take a look at the before and after pictures of the tutorial image:
As you can see, the before image on the left was very flat and not particularly vivid. The image on the right was adjusted in Photoshop to add contrast and clarity.
Levels is one of the more popular methods of adjusting photos. It's very flexible, yet not too complex. You can get to levels by going to the menus Image --> Adjustments --> Levels.
The levels dialogue box displays a histogram and some small arrows called "sliders."
The histogram is a graph showing all of the values across the spectrum of the image. It could best be described like this: The left side of the graph is the shadows and blacks. The right side displays the highlights and whites. Imagine if we took every pixel from the image and sorted them into stacks; from darkest to brightest. This graph is what we would come up with.
Notice from this graph, there are hardly any black tones, and hardly any white tones, as the graph is rather flat on the edges.
To adjust this image, we move the three slider arrows at the bottom to their appropriate settings. The black slider arrow defines the black point, that is the darkest part of the photo. The white slider defines the white point, the brightest part of the photo that is white. The middle slider adjusts what are called the mid-tones.
Drag the outside sliders inward until the are lined up with the edge of the histogram.
You will immediately notice how the contrast picks up tremendously. That's because this image didn't have a very solid white or black point. We've moved the sliders to define the darkest tone of this image to become darker -- blacker. And respectively with the white tones.
Next, adjust the middle slider to set the midtones of the image. This adjusts the overall brightness of the image. Watch out, too bright will muddy the shadows, and too dark will make it difficult to see faces.
Adjusting colors using levels
You can also adjust the colors of an image using levels. Simply select the Channel option at the top to choose one of the three primary colors.
While it might seem that you only have three choices, you actually have six. Each choice allows you to either increase or decrease that particular color from the image (sliding either the white point, black point, or mid-tones). If you subtract a particular color, it's relative secondary color will start to emerge in the image.
For example, let's say you want to add some yellow to your image. Well, there isn't an option for yellow, but you can get yellow by subtracting blue. Set the channel to blue, and slide the black slider inward:
There are other, perhaps more exact, ways to do this using the Color Balance dialogue. That's beyond the scope of this tutorial, however.
Variations is a really easy way to adjust the levels of a photo. This method is a bit more crude, but sometimes this tool is easy enough to do the trick.
When you select variations, you're presented with a window dialogue that shows several copies of your image. The two images at the top are depicting the "original" image as it appeared when you opened variations, and "current pick" which shows you how the image will change.
To change the image, simply click on one of the options below. For more yellow, click on the yellow box, and it will add an increment of yellow to your "current pick."
To lighten or darken, click on those images at the right.
You can fine tune the way each increment of color or brightness affects your image with the tools at the top:
Adjusting these settings will affect how each method (like clicking on yellow) will affect the image. You can adjust by shadows, midtones or highlights. The slider will affect how fine each step will take.
"Show Clipping" will colorize the image with indicators that the color is so vibrant it is maxed out; or rather set to such an extreme range that it's lost its ability to go any further. These clipping indicators won't show up in your final image, as crazy as they look. It's just a way to see which part of the image has reach its limit.