5) For start, let us deal with the black triangle, or the black point slider as shown in figure 7 . If you move it to the right, any piece of pixel information in its left will be turned into dark.

6) When you click “OK” in the Level dialog box {see figure 8 }, this point will become your new zero point (the new black point slider will start from where you have stopped the previous one).

7) The white triangle at the opposite end of the histogram line acts in a similar manner to the black point slider. If you move it to the left, everything in its right will be turned into absolute white. The two sliders act in an independent manner: if you move the black point, you will not affect the highlights and vice-versa, wherever you will move the white slider, the shadow areas will remain intact. That is why choosing the Levels options offers you greater flexibility than the simple Brightness/Contrast slide bars {see figure 9/font>}.

8) Before starting up to edit the picture, be sure to have the “preview” box checked so that you will see in real time all the effects the changes cause on the image {see figure 10}.