Using Levels to correct image contrast > Step 1

Digital photographs with good contrast contain an even spread of tones between black and white. In 24 bit colour images, this means that pixels are distributed between the values of 0 for black, and 255 for white.

Image editing programs like Photoshop and Photoshop Elements contain tools for viewing the spread of tones in digital images. The Levels feature displays a graph view of all the pixels in a picture. The height of the graph at any one point indicates the number of pixels in the image with this particular tonal value.

The levels feature also provides input and output sliders which are used to alter the spread of tones in an image. Changes in contrast and brightness can be achieved by manipulating these sliders.

To view the Levels feature select:

• Photoshop - Image>Adjustment>Levels
  
• Photoshop Elements - Enhance>Brightness/Contrast>Levels