Datasheet

Part I: The Basics of Color Editing

color file sizes as small as possible. Computers couldn’t display 16.7 million

colors back then, so monitors that showed images in only 8-bit mode used

index color.

Web pages still use index color today, in the form of GIF-format files that are

limited to 256 colors. The Save for Web option in Elements allows you to save

files in the GIF format, if you want.

The main advantage to the GIF format is the ability to keep graphic elements

clean and sharp on Web pages, unlike JPEG files, which can add distracting

visual artifacts to graphics when the JPEG files use high compression set-

tings. But index color doesn’t allow the use of color profiles.

Grayscale

You can think of grayscale as the black-and-white image mode, in terms of

black-and-white photos. Just a single channel is used to describe image tone

without color information. Grayscale has 256 distinct gray levels supported

in 8-bit mode and more than 40,000 gray levels in 16-bit mode.

Grayscale mode has advantages if you like to work with classic black-and-

white photography. Grayscale files are just one-third the size of an RGB file,

so you get much faster computer performance and can store more files on

your hard drive.

If you want to tone, paint, or tint a grayscale creation, you must convert to

RGB mode to do so.

Grayscale supports embedding special profiles to indicate the display

Gamma used and also for dot gain if the file is for traditional press use.

Bitmap

Bitmap is a 1-bit file format. One bit means that only two tone values are

supported — just white and black with no grays. Bitmap can simulate gray

values by using a display we call

dithering, which places the black and white

pixels in a pattern to visually appear as grays.

Elements users should probably see bitmap as more of an image appearance

than as a standard file format to use. The main advantage to this mode is the

small final file size, compared to grayscale mode. Convert a grayscale file to

bitmap, play with the options available for conversion, and you might find a

visual style that you like.

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