Adobe PHOTOSHOP ELEMENTS Manual page 104

CHAPTER 4
96
Making Color and Tonal Corrections
Using the Invert command
The Invert command inverts the colors in an
image. You might use this command to make a
positive black-and-white image negative or to
make a positive from a scanned black-and-white
negative.
Note: Because color print film contains an orange
mask in its base, the Invert command cannot make
accurate positive images from scanned color
negatives. Be sure to use the proper settings for color
negatives when scanning film on slide scanners.
When you invert an image, the brightness value of
each pixel in the channels is converted to the
inverse value on the 256-step color-values scale.
For example, a pixel in a positive image with a
value of 255 is changed to 0, and a pixel with a
value of 5 is changed to 250.
To use the Invert command:
Do one of the following:
Choose Image > Adjustments > Invert.
•
Create an Invert adjustment layer. (See "Using
•
adjustment layers and fill layers" on page 181.)
Using the Equalize command
The Equalize command redistributes the
brightness values of the pixels in an image so that
they more evenly represent the entire range of
brightness levels. When you apply this command,
Photoshop Elements finds the brightest and
darkest values in the composite image and remaps
them so that the brightest value represents white
and the darkest value represents black. Photoshop
Elements then attempts to equalize the
brightness—that is, to distribute the intermediate
pixel values evenly throughout the grayscale.
You might use the Equalize command when a
scanned image appears darker than the original
and you want to balance the values to produce a
lighter image. Using Equalize together with the
Histogram command lets you see before-and-after
brightness comparisons.
To use the Equalize command:
Choose Image > Adjustments > Equalize.
1
If you selected an area of the image, select what
2
to equalize in the dialog box, and click OK:
Equalize Selected Area Only to evenly distribute
•
only the selection's pixels.
Equalize Entire Image Based on Selected Area to
•
evenly distribute all image pixels based on those in
the selection.
Using the Threshold command
The Threshold command converts grayscale or
color images to high-contrast, black-and-white
images. You can specify a certain level as a
threshold. All pixels lighter than the threshold are
converted to white; and all pixels darker are
converted to black. The Threshold command is
useful for determining the lightest and darkest
areas of an image.