How to use Levels
In this tutorial I will teach you how to adjust a photo using Levels. Levels is a tool not so advanced as curves , but it does almost the same job if you learn how to use it correctly. With levels you can adjust the white balance or you can tweak the brightness/darkness of a certain type of range (Shadows , Midtones , Highlights).
This tool has two methods of using: you can apply to the original layer by going to Image – Adjustments – Levels (CTRL+L) or by creating a new adjustments Layer from the bottom of the Layers window – the third button.
Make a new adjustment layer because this is a method preferred by most users because you can delete or modify the settings later. A new window will show up. You will probably not understand too much from this , but I will clarify that in a moment.
For the moment you should only work on RGB as channel because the individual channel request more attention from you. As you will get more confident with this tool , you could work only on the Blue or Red or Green channel. Working with an individual channel let you correct some unwanted color hues of the image. If you don’t use it correctly you could make the effect worse , that is why you should only work on RGB for the first time.
You see that under the histogram are three pointers. The black one is for Shadows , the gray one is for Midtones and the white one is for Highlights. You will notice that if you pull the black pointer to the right , the gray one goes with it. The same thing applies if you drag the white pointer to left.
You should find the balance by making the Shadows adjustments first , then the Highlights and after that drag the middle one to the left/right until you see the image as you want.
You may also see the two pointers under the black to white bar. This adjusts the Shadow and makes them lighter and the Highlights and makes them darker. You should work on these after you finished with the ones above.
With this tool you can adjust the brightness and the contrast of the image if you tweak the balance. You can also use the individual channels for adjusting the tint of an image.
The main feature is the three eyedroppers from the left of the histogram. If you want to set the white balance correctly , use the middle eyedropper and look for a neutral gray tone in the photo. Neutral gray is tone like the one of the window that displays the levels settings. If you find it correctly , the image will look as good as possible.
You also have on the top of the window some settings. I selected Default , but you may select Increase Contrast or other setting that suits best for your photo.
This tool is not as powerful as Curves , but it is easy to use and can do the job as well as Curves.