This dictionary covers design, prepress and printing topics.
It was created with the help of S. Schwartz.

A-B-C-D-E-F-G-H-I-J-K-L-M-N-O-P-Q-R-S-T-U-V-W-X-Y-Z

jaggies
Also see aliasing. The ragged edge of an image that is produced when a diagonal or circular line is scanned into a system, and either displayed as pixels on a monitor or an output on an imagesetter. Jaggies are caused by a lack of resolution. Sometimes called “stair steps.”

Jaguar
Code name for Mac OS X 10.2

Jaz
A removable disk technology, that was developed by Iomega. There are two versions, capable of storing either one or two gigabyte of information on a disk measuring about 10 by 10 centimeters.

JBOD
Abbreviation for Just a Bunch Of Disks: term used to describe a array of hard disks that do not use RAID technology.

JFIF
Abbreviation for JPEG File Interchange Format: a file format used to store JPEG compressed images. Most people simply refer to it as JPEG. More information is available on this page.

jitter
A temporal phenomenon, it describes an spurious variations in an otherwise regular wavetrain.

JND
Abbreviation for Just-Noticeable Difference

job tracking
In print production, the act of recording the whereabouts of all components of each job and the production time used for each function.

Joliet
CD-ROM recording format that is commonly used on Windows computers. It is based on the ISO-9660 standard for writing CD-ROMs but it allows for longer file names.

JPEG
Abbreviation for Joint Photographic Experts Group: compression algorithm named after the committee that defined it. More information about the algorithm can be found on this page, while this page discusses the JPEG file format (which is actually called JFIF).

juke box
A device that will store and replay many optical discs or data tapes.

justification
The typographic process of setting lines of type so both left and right ends are flush to the margins so lines of type appear vertically aligned. Achieved by filling the type line until the last word or syllable fits, rather than by expanding or contracting the word and letter spaces to fill out the line to its specified measure.

justified text
Lines of set type that align on both their left and right hand sides. The alternative to justified text are ragged right, ragged left and centered.