You can manipulate the brightness and contrast for an image by choosing Image->Adjustments->Brightness/Contrast. When you perform this action, the following dialog box will appear.

 

 

Here you can use the slider switches to adjust the level of brightness (light or dark) and the level of contrast in the image. Contrast can be described as the differences in colour and light in an image that helps to distinguish the image’s various elements. You can enter values directly in the value fields provided if you wish.

 

 

In the image on the left, the Brightness slider has been set to +8 and the Contrast slider has been set to +44.

 

Once again, a check in the Preview checkbox allows you to see your adjustments on the image as you make them. This way, you can see what the changes look like before you commit to them.

 

As with the Hue/Saturation dialog box, pressing the Alt key lets you toggle between Reset and Cancel. If you click the Reset button, the sliders will be set to the default positions at a level of zero.

 

When you are satisfied with your brightness and contrast adjustments, click the OK button to implement the changes. Keep in mind that this method of configuring brightness and contrast applies to the entire image (you have no control over how isolated these effects will be using this method).