Bitmap: a digital image, comprised of a large number of tiny squares(pixels), each of which is represented in a computer’s memory by a number corresponding to the colour or tone of that square.
Blueline (also Dyeline, Dyelux): single colour proof made directly from the output film.
Bromide: a high quality photographic print on coated white stock, can be used by printers to make plates. No longer common.
Chromalin: as above, but simulating Pantone colours.
CMYK: acronym for the ink colours used in four colour printing: Cyan, Magenta, Yellow and Black.
Digital Printing: As plates are not used, each individual print can be varied (with a recipient’s name, for example). Low setup costs and fast turnaround make it quite popular for short run printing and on-demand book printing. Offset printing still has an edge in longer runs.
Dithering: a means of simulating a continuous tone by varying the distribution of black dots. Used by inkjet printers. (See also HALFTONE).
Dots per Inch (dpi): measure of resolution in a bitmap. The measurement refers to the number of dots along each side of an inch. Thus, at 300 dpi, each square inch actually contains 90,000 dots. Compare this with 72 dpi required for web images (5184 dots per square inch) and you will see why, in storage terms, web images are much smaller than print images, and also why web images are rarely large enough for print purposes.
Duotone: used to describe two overlapping halftones. A duotoned image may use two (or more) spot colours, which, when combined, create the illusion of a third colour. May be created and manipulated using Photoshop (which also allows for the creation of tritones and quadtones), and used in a variety of design packages.
Encapsulated Postscript (EPS) File: a graphics file format that can be generated from within a variety of packages, and is device independent. Used less frequently in recent times, with native Illustrator format (Ai) files or PDFs preferred.
Film: output medium used by printers to make a plate (see PLATE). Computer to Plate is increasingly common, eliminating film from the process.
GIF: An image file type designed for use with the Internet. Keeps image file sizes small by limiting the number of colours used to 256 or less. If not carefully managed, can result in noticeably poor quality images.
Font: a set of type in the same style. Italic and bold versions are considered to be separate fonts.
Greyscale: An image rendered entirely in tones ranging from solid black to white. Occupies less space (in terms of file size) than a colour image.
Halftone: simulation of a continuous tone image by use of regularly placed dots of varying sizes. Used in offset and digital printing, and on laser printers.
JPEG: File compression protocol designed to reduce the file size of greyscale or colour images. Causes some loss of image quality, depending on the degree of compression chosen.
Indexed Colour: A means by which a colour image can be reduced to 256 or less colours, thus dramatically reducing file sizes. Commonly used when preparing files for the Internet (see also GIF).
Kerning: spacing of letters on a line, may be specified by hand by some purists, or more commonly, automatically.
Leading: space between lines of text. Also known as linespacing. A generous measure is generally thought to improve readability.
Lines per inch (lpi): The measurement describing the fineness of a halftone, referring to the number of rows of dots per square inch, and generally governed by the quality of the printing stock. For example, newspapers might print at 100lpi or less, and a good quality magazine at 175lpi.
Offset Printing: standard commercial printing technology used for most paper-based print jobs. The image is ‘offset’ onto a rubber covered cylinder,from which the image is printed. Under increasing threat from digital printing
Open Type: A relatively new standard for typefaces, designed to replace both True Type and Type One. An OpenType font can support over 50,000 glyphs, plus advanced typographic controls, alternate ligatures, kerning pairs and so on.
Orphan: single line from beginning of paragraph, the remainder of which has flowed onto the next column. Acceptable, if not ideal.. (see also WIDOW).
Pantone Colours: proprietary scheme of ‘spot’ colours which use precise proportions of certain inks to ensure reliable colour outputs. Other, less widely used schemes also exist, including Focoltone and Trumatch.
Picas: unit of type measurement. One pica equals 12 points (approximately 1/6 of an inch).
Pixel: dot of light on computer screen of which images are composed. Most modern monitors use tiny clusters of pixels of red, blue and green to simulate all other colours (also known as rgb).
Plate: sheet of plastic, paper or metal from which an image is printed.
Points: A unit of measurement used in typesetting. There are 72 points (pts) to an inch and exactly 12 points to a pica.
Postscript: a widely used language designed by Adobe Systems to allow reliable output of publishing files on laser printers and high resolution imagesetters.
Press Proof: last chance to view a job before it is printed. Used on large print runs, often to establish colour accuracy.
Scanner: device that converts an image into digital form.
Spot Colours: special ink colour (see Pantone) used to accent or highlight a job, or match a corporate colour. (also see DUOTONE) .
TIFF: Tagged Image File Format, popular graphics file format used for high resolution images on Mac and PC.
Tiling: method of printing a document page that is too large to be output as a single sheet, breaking it up into overlapping portions.
Transparency/Tranny: a colour positive photographic image on transparent film.
TrueType Font (TTF): Font font file type predominantly used on PCs, but also found on Macs. Cheap TTF files are available, but many are of poor quality. (See FONT).
Type 1 Font: font file type designed and promoted by Adobe Software. Many great typefaces available, though some are quite expensive.
Widow: single line at end of paragraph, when isolated at top of next column. To be avoided. (see ORPHAN).
WYSIWIG: What You See Is What You Get, the claim made by some design packages comparing the image on screen to that which an output device actually prints out. Unfortunately, not always the case, and print proofs are always advisable for medium to large jobs.