Instruction manual

without substantially affecting the highlights and shadows, where simply

brightening the image with a brightness slider tends to wash out the dark

regions and increase the intensity of the highlights. Using the middle slider

can often bring more detail out of a shadowy area, and you won’t have to

worry about your blacks or whites turning gray.

Correcting Color Cast

Most Levels controls provide another way to set black and white points

and neutralize color casts. Look in the histogram dialog boxes (shown above)

on the lower right side above the Preview checkbox and you’ll see three

eyedropper icons.

The White Point eyedropper lets you set the white point in the image by

simply clicking on something white in the image. Similarly, the Shadow

eyedropper lets you set the black point by clicking on a black area

The Gray Point (neutral) eyedropper lets you define something in the

image that’s supposed to be neutral (or gray). When you use this feature, the

program automatically performs separate Levels adjustments on the

individual red, green and blue color channels so the resulting tone is neutral.

This is analogous to white balance; by setting the neutral point correctly all

the other colors fall into line and the color cast is eliminated (in fact, this

technique can sometimes be used to correct bad white balance in JPEG

photos).

If you like the results, click on “OK” to accept the changes. If not, you

may have clicked the eyedropper on a pixel that wasn’t truly neutral: just click

again in a different area until you find a point that results in a neutral image.

[All eyedroppers work this way. If you don’t like the initial result, click again in

another location.]

With practice, you’ll learn which control adjustments work best for

particular situations.

Note

If you have Adobe Photoshop, the “Curves” tool (Image > Adjust > Curves)

does everything “Levels” does and also provides a few other capabilities.

Levels lets you edit the black, white and midpoints, whereas Curves allows

you to set up to 14 different points in any location along a curve to allow

precise edits of particular tonal ranges.

Data Loss

Adjusting Levels will remove data from an image, but this type of data

loss is not readily apparent on-screen and is not at all noticeable on a

printout. However, if you make two or three more edits after you make the

Levels adjustment, the photo might visibly degrade.

This is why it is important to think carefully about edits in order to

minimize data loss.

Automatic Enhancements

For CAP purposes, the only adjustment recommended is the tone

adjustment discussed above. However, you should familiarize yourself with