214 Glossary
Shareware A creative way of distributing software that lets
you try a program for up to 30 days before you’re expected to
pay for it.SLR Single-lens refl ex. In an SLR camera, the image created
by the lens is transmitted to the viewfi nder via a mirror, and the
viewfi nder image corresponds to the actual image area.sRGB Standard RGB (Red, Green, and Blue) is an RGB color
space that was originally created by Hewlett-Packard and Micro-
soft Corporation. sRGB defi nes the red, green, and blue prima-
ries as colors where one of the three channels is at the maximum
value and the other two are at zero. The sRGB color space is
designed to match typical home and offi ce viewing conditions,
rather than the darker environment typically used for commer-
cial color matching. sRGB is sometimes avoided by publishing
professionals because its color gamut is not big enough, espe-
cially in the blue-green colors, to include all the colors that can
be reproduced in CMYK printing.
Thumbnail An old design-industry term for “small sketch.”
In the world of digital photography, thumbnails are small, low-
resolution versions of your original image.TIFF Tagged Image File Format is a bitmapped fi le format
that can be any resolution and includes black-and-white or color
images. TIFFs are supposed to be platform-independent fi les, so
fi les created on your Macintosh can (almost) always be read by
any Windows graphics program.
Transfer rate A measurement of the average number of bytes per
unit of time passing between disk storage and processor storage.TTL Through-the-Lens. In this system, the camera measures
the actual light entering the lens.TWAIN Not an acronym, although some pundits insist it
stands for “Technology Without An Interesting Name.” A hard-
ware/software standard that allows users to access scanners and
other hardware peripherals from inside Windows applications,
although the TWAIN standard can be found on Mac OS
computers too.
UDMA Ultra Direct Memory Access. This is actually a hard-
disk standard that allows certain hardware subsystems within the
computer (or digital SLR) to access system memory for reading
and/or writing independently of the central processing unit.
Computers and cameras that have DMA channels can transfer
data to and from devices with much less CPU overhead than can
computers without a DMA channel.
Undo One of the most useful tools, commands, and/or
features an image-enhancement program can have. It lets you