Step 2-
Set the Black Point
The first step in optimizing the image is to set the black point. This creates areas of absolute black in the image, which is necessary for strong contrast and deep shadows.
To set the black point, open the image in Photoshop and select Image>Adjust>Curves. In the dialog that appears, click on the black point Eyedropper, which is the black tipped eyedropper icon just below the Auto button. Now move your cursor into the image, looking for the darkest pixel value you can find. It helps to have the info palette open and visible so that you can monitor pixel values exactly.
Click on the darkest pixel to darken down the image. Its important to note that when you set the black point, every pixel value that is below the selected pixel will also reduce to pure black. Click on a mid tone for example, and half your image turns black. That's why its important to select the darkest values in the image. In this case the image appears too dark, but the next step will lighten it up again.
