Instruction manual

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This adjustment is best done with the person who took the photo present,
as it quickly enables you to make the photo match the colors and contrasts
the Photographer observed at the scene.
As we discussed in Chapter 2, there's no such thing as a good or bad
histogram. However, a histogram that shows a large flat area on either end of
the graph is most likely in need of some adjustment (see the example below).
From the histogram you can determine the image's darkest shadow and
brightest highlights, which are called the black point and white point. In fact,
it's the range between these two points that defines the dynamic range (also
called the tonal range, or contrast) of the image. If the image is low contrast,
you can also tell if it's low-key or high-key from the histogram. A low key
image has details concentrated at the dark end of the scale while a high-key
image has them concentrated at the light end.
If there is enough detail, even if the image is somewhat off, it can be
corrected in a program such as Photoshop Elements using the “Levels”
command or in “Picture Window” using the ‘Brightness Curve’. These
controls allow you to adjust the shadow, mid, and highlight areas
independently without affecting the other areas. This lets you lighten or
darken selected areas of your photos without losing detail.
In Photoshop Elements the ‘Levels’ dialog box (‘Tone Adjustment’ in
some programs) gives you five dragable triangles to adjust the distribution of
brightness in your image: