Using Levels in Photoshop

Once you have named your adjustment layer, the levels control pop-up menu will open. From here you can select the channel to be adjusted, output levels, auto adjustment, and input levels.

Input levels will be your main tool for adjusting your image. The black arrow on the left represents shadows, the grey arrow represents midrange, and the white arrow represents highlights. The curve basically shows you the density of the data in the ranges. These mountains and valleys show you the range of the image. A good rule of thumb is to bring the black and white sliders towards the middle so that they are just underneath the edge of the "mountain" nearest to them. The midrange grey arrow can then be adjusted for fine-tuning the image.

Output levels allow you to change the images tonal range. Instead of pure black to pure white you can adjust the maximum whiteness or maximum blackness to a shade of grey if desired.

The eyedroppers are quick step to editing levels. Click the black eyedropper and then click on the part of your image that should be black to have the program adjust levels and color hue accordingly. Follow the same process for the grey and white eyedroppers if needed.

As long as the preview button is checked you will be able to see the results of your changes in real time. Once your image looks like you want it to just click the OK button and you are finished adjusting levels.