A quick note regarding the correct usage of typographical spacing in Graphic Design.

Unless you are using a mono-spaced typefont on your computer (e.g. Courier), then you should not be using “two spaces after a period at the end of a sentence”. The correct typographical width for a space between two words or sentences is the width of the letter “i”. (To let and Toilet is a good example). Because typewriters could not differentiate between the width of a small letter such as an “i” or a wide letter such as an “m” then two spaces were introduced to correct the visual problem of sentence breaks when using a typewriter. This has been the normal procedure for secretarial training ever since it’s introduction. However, as we no longer use typewriters but word processors or computers that can handle “proportional” fonts, then we revert back to the original typesetting rule of one space after a period. Otherwise we end up with “rivers” on a page where you get a visual whitespace running down the length of a page…

Most DTP programs have a function to strip the double spaces inserted by typists trained with the old school of thought, as do all web browsers… try getting two spaces in between words in HTML without the use of
Unfortunately Microsoft® Word (say no more!) is one of them that doesn’t…


  • Additive Primary Colours: These three colours create all other colours when direct light (reflective) or transmitted light (such as on your monitor or television set) illuminates an object or a scene (refer to RGB).
  • Alphabet: The characters of a given language, arranged in a traditional order.
  • Aliasing: Visibly jagged steps along a angled lines or objects, due to sharp tonal contrasts between pixels.
  • Analogue: Continuously variable signals or data.
  • Anti Aliasing: A technique reduced for the jagged appearance of aliased bitmapped images, usually by inserting pixels that blend the boundaries between adjacent colours.
  • Artifacts: Image imperfections caused by compression.
  • Ascender: The part of upward reaching letters, such as ‘b,’ ‘d,’ ‘f,’ ‘h,’ ‘k,’ and ‘l,’ that extends up above the x-height. An ascender should be in proportion with the x-height for legibility.
  • Ascender Line: The imaginary horizontal line that represents the upper-most point of an ascender.
  • ASCII: (American Standard Code for Information Interchange) An acronym to describe a computerised numbering scheme used to represent text characters. Pronounced “ask-ee.”
  • ATM: (Adobe®Type Manager) A program that improves your screen display by imaging fonts directly from their Postscript® language font files.
  • Authoring Tools: Creation tools for interactive media.
  • Baseline: The imaginary horizontal line on which all letters in a font rest. Leading is measured baseline to baseline. Also known as the reading line.
  • Batch scanning: Sequential scanning of multiple originals using previously defined unique settings for each.
  • Bézier Curve: Mathematical equations commonly used to describe the shapes of electronic illustrations and characters in electronic typography. The Bézier curve was named after Pierre Bézier, a French computer scientist who developed a mathematical representation used to describe that curve.
  • Binary number system: A counting system used in computers consisting of 1’s and 0’s.
  • Bit: Binary digit. The smallest unit of information in a computer, a 1 or a 0. It can be defined by two conditions (on or off).
  • Bit depth: The number of bits used to represent each pixel in a image, determining its colour and tonal range. Specifically a bit depth of 2 = black and white pixels. Bit depth of 4 = 16 colours of greys. Bit depth of 8 = 256 colours or greys. Bit depth of 16 = 65,536 colours. Bit depth of 24 = (approximately 16 million colours).
  • Bitmap: A matrix of individual dots or pixels that make up the graphic display. Each pixel (or picture element) corresponds to bits in the computer processor’s memory. Bitmapped graphics as opposed to vector graphics or object orientated graphics. Bitmapped graphics are what a computer can display, because it’s a pixel based medium.
  • Boldface: A dark typeface used for emphasis, usually heavier in weight.
  • Byte: A measurement equal to 8 bits of digital information. The standard measurement of a file size, kilobyte, megabyte, and gigabyte are multiples of the byte.
  • Calligraphic: This usually refers to Roman or Italic alphabets which appear to have been written with a pen or brush. Derived from the Greek word kalligraphia, which means beautiful writing.
  • Cap Height: The height of uppercase letters.
  • Clip Art: Public-domain art, either in books or on disks, that you can use free of charge and without credit of publication.
  • CMS: Colour management system. This ensures that colour uniformity across input and output devices so that final printed results match the originals.
  • CMYK: Cyan, magenta, yellow and black are the base colours used in the printing processes. CMY are the primary colorants of the subtractive colour model.
  • Codec: Compressor/Decompressor. A piece of soft ware that encodes and decodes movie data.
  • Compression: Reduction of the amount of data required to re-create an original file, graphic or movie. Compression is used to reduce the transmission time of media and application files across networks.
  • Cursive: First used in the 16th Century, these typefaces imitate hand writing. Script letters and cursive type appear to be drawn with pen and ink. Unlike script, however, cursive letters are not joined.
  • DCS: Desktop colour seperation. An image format consisting of four separate CMYK PostScript files at full resolution , together with a fifth EPS master for the placement in documents.
  • Descender: The lowest portion of letters such as ‘g,’ ‘j,’ ‘p,’ ‘q,’ and ‘y’ that extends below the baseline, or reading line of type.
  • Descender Line: The lowest line that a character’s descender extends to, like the bottom stem of the lower case ‘j’ or ‘y.’
  • Digital: Data or voltages consisting of discreet steps or levels, as opposed to continuously variable analogue data.
  • Dingbats: Once known as ‘printer’s flowers,’ these are small decorative marks, bullets, or symbols that usually make up a specialty typeface. Zapf Dingbats is one well known example of a dingbat font.
  • Direct-to-plate: The direct exposure of image data onto printing plates, without the intermediate use of film.
  • Direct-to-press: Elimination of intermediate film and printing plates by the direct transfer of image data to printing cylinders in the press.
  • Dithering: The positioning of different coloured pixels within an image that uses a 256 colour palette to simulate a colour that does not exist in the palette. A dithered image often looks noisy, or composed of scattered pixels.
  • Dmax: The point of maximum density in an image or original.
  • Dmin: The point of minimum density in an image or original.
  • Downloadable font: A font file that contains character descriptions that are copied from the computer and are temporarily stored in the printer’s memory while a document is printing.
  • DPI: Dots per inch. The measure of resolution for a video monitor (screen) or printer. High- resolution printers are usually 1200dpi. Laser printers typically have a resolution of 600dpi; screens are usually 72dpi. Drop Cap: An oversized capital letter used at the start of a paragraph. Drop caps occupy two or more lines of body copy.
  • Drum scanner: An image scanning device in which originals are attached to a rotating drum.
  • Em: A unit of measure, which is the square of a face’s point size. Traditionally, the width of a face’s widest letter, the capital ‘M.’ For instance if the ‘M’ is 10 points wide, an em is equal to 10 points.
  • EPS: Encapsulated PostScript®. A computer document file format jointly developed by Altsys, Aldus®, Adobe® and Quark®, which expedites the exchange of PostScript® graphic files between applications. Also known as ‘EPSF.’
  • Flatbed scanner: Any scanning device that incorporates a flat transparent plate, on which original images are placed for scanning. The Scanning process is linear rather than rotational.
  • Font: In modern usage, the term ‘font’ is often confused with ‘typeface’ and ‘family.’ Traditionally, the font represents a complete set of characters or symbols, which share the same size and style. For example, 12 point Goudy Oldstyle Bold is a f ont. Fonts can be as small as the basic alphabet or up to hundreds of characters. Some languages like Japanese, can exceed these numbers, which make them difficult to access from a standard keyboard. Derived from the word ‘found’ as in typefoundry.
  • GIF: A bitmapped colour graphic file format. Gif is commonly used on the Web because it employs efficient compression methods.
  • Gothic: In modern usage, Gothic refers to sans serif mono weighted letters. These have little contrast of thick and thin lines, and no ornamentation, yet they retain the intensive boldness of traditional Gothic style. After the invention of typography by Gutenberg in AD 1450, the traditional Gothic style of lettering almost disappeared.
  • Greyscale: A continuous tone image comprising black, white and grey data only.
  • Grey levels: Discrete tonal steps in a continuous tone image, inherent to digital data. Most continuous tone images will contain 256 levels per colour.
  • Halo: A light line around object edges in a image , produced by the USM (Unsharp masking) process for sharpening images.
  • Halftone: A simulation of continuous tones by the use of black or overlapping process colour dots of varying size and position.
  • Hue: The colour of an object perceived by the eye due to the fact that a single or pair of RGB primary colours predominates.
  • Imagesetter: A device used to record digital data (images and text) onto a monochrome film or offset litho printing plates by means of a single or multiple intermittent light beams. Colour separated data is recorded as a series of slightly overlapp ing spots to produce either solid areas of line-art or halftone dots for printing continuous tones.
  • Initial Cap: Large, capital letters (often ornamental) which are found at the beginning of paragraphs or chapters. These date back to the early days of European manuscripts where they where and still are considered to be works of art.
  • Interlaced GIF: The GIF file format allows for interlacing which causes the GIF to load into a browser quickly at low resolution and then come into full crisp resolution.
  • Italics: Best used to set off quotes, special phrases, foreign words, italic letters have a redesigned structure that allows them to slant to the right. The first italic type was designed by Aldus Manutius in AD 1501 and was based on the hand writi ng style of that time.
  • JPEG: Means Joint Photographic Experts Group, the name of a image file format based on the various file compression techniques developed by this organisation.
  • Justified Text: Text that lines up with both the left and the right margins.
  • Kerning: The process of improving appearance and legibility by adjusting the white space between certain paired characters, such as ‘Ty,’ and ‘To,’ or ‘Ye,’ which are known as kerning pairs. Manual kerning allows the desktop publisher to move letter s either closer or farther apart to adjust and improve the space between them. Automatic kerning is done on the computer by using a kerning table that contains pre-defined font specific kerning pairs.
  • Leading: Pronounced “ledding,” this is the space (measured in points) between the rows of text, from baseline to baseline, (ie 12 on 12 means there is no additional leading; 12 on 13 is 12 point type with one additional point of leading.) This term is taken from the days when thin strips of lead were placed between lines of type to space them apart.
  • Left justified: Type that is aligned with its left margin.
  • Letter spacing: Separating all the letters with spaces. Best used to modify headings, this should be applied with caution since too much letterspacing makes copy difficult to read.
  • L.P.I: Lines per inch, a unit for measuring screen ruling.
  • Lossy: Image compresion that functions by removing minor detail and/or colour variations, causing visible loss of detail at high compression ratios.
  • LZW: The Lempel- Ziv- Welch image compression technique.

  • Moiré: A repetitive interference pattern caused by overlapping symmetrical grids of dots or lines having a different pitch or angle.
  • Monochrome: Single coloured. An image or medium displaying only black and white or greyscale information. Greyscale information displayed in one colour is also monochrome.
  • Monospaced: Single spaced. A non-proportional typeface as used by typewriters and email programmes, e.g. Courier.

  • Noise: Refers to random, incorrectly read pixel values, normally due to electrical interference or device instability.
  • Non-lossy: Image compression without loss of quality.
  • Oblique: A right slanted version of a Roman typeface without changes to the letter’s design. Often confused with italic.
  • OCR: Optical Character Recognition. The analysis of scanned data to recognise characters so that these can be converted into editable text.
  • OLI: Shot for object linking and embedding, this is a way of sharing files between programs.
  • Outline Font: A font that is defined by drawing the black contour of white space that makes up each character.
  • Paint-Type graphics: Graphics represented by dots, or pixels, which can be individually manipulated on the screen. These graphics may be distorted or lose resolution (jagged edges appear) when resized, see also bitmap.
  • Pantone colours: A standardized system of colours, available in printing inks, papers, markers and other materials that can be specified by desktop publishing programs. Also referred to as PMS (Pantone Matching System)
  • PDF: Stands for portable document format, a platform independent file format developed by Adobe® for sharing files between computers, across networks and over the Internet.
  • Pica: A typographic measurement that has survived the digital revolution. A computer pica is equal to 12 points ( one-sixth of an inch). 12points =1 pica; 6 picas=1 inch; 72 points=1 inch.
  • PICT format: A Macintosh® graphics file format.
  • Pixel: Stands for (PICture ELements). Pixels are square dots that represent the smallest unit displayed on a computer screen. The standard computer monitor displays about 72 pixels per inch. Graphics and characters are created by turning pixels on or off.
  • Point: In modern desktop publishing, one point is defined to be equal to 1/72 of an inch. The traditional point measurement was slightly more or less than the 72 points to the inch.
  • Point size: The height of the type body. A standard type measurement system was originally by a Parisian type founder Pierre Fournier le jeune in 1737. In the days of metal type, the point size was the total number of points in the height of metal type, including the ascent and descent of the letters and the metal above and below the letters.
  • Posterisation: The conversion of continuous tone data into a series of visible tonal steps or bands.
  • PostScript:® Adobe System’s page description language. Graphics programs like Macromedia® FreeHand use PostScript® to create complex pages, text and graphics onscreen. This language is then sent to the printer to produce high quality printed text a nd graphics.
  • PPD File: A file that describes the particular characteristics of a specific printer. PPD files are used outputting a file to a printer. Each printer comes with its own PPD.
  • Rasterization: The process of converting outlines into bitmaps. The outlines are scaled to the desired size and filled by turning on pixels inside the outline.
  • Rendering: The actual placement of rasterized pixels on the monitor’s display. Refers to both graphic objects and type. Also called rasterization.
  • Resolution: The number of dots in an image’s screen display or printed output. Resolution refers to the number of dots per linear inch. DPI.
  • Reverse type: White characters on a dark background.
  • RGB: Red, green, and blue are the primary colours of light perceived by the eye.
  • RIP: Raster Image Processor. Converts graphics and fonts into raster images, which are used by the printer to draw onto the page.
  • Roman: In Macintosh® font menus this is called Plain meaning text that has no style applied to it.
  • Sans serif: A type face with out serifs. Sans serif type is more legible in headings than in long passages of text.
  • Script: Script letters are joined and should not be confused with cursive, which are not connected. Often difficult to read.
  • Serif: Small finishing strokes on the arms, stems, and tails of characters. Serif typefaces are usually used for text, since the serifs form a link between letters that leads the eye across a line of type.
  • Style: A visual variation of a basic typeface used to create emphasis. The four basic computer styles are Plain, Bold, Italic, and Bold Italic.
  • Text: The main body of a printed document or book. Also called Copy.
  • TIFF: Tagged Image File Format, a format for electronically storing and transmitting bit-mapped, grey-scale, and colour images.
  • Tint: A percentage of black or a colour that can be edited or specified through a colour palette. (Tone refers to the same thing).
  • TrueType: An outline font format developed by Apple® Macintosh and adapted by Microsoft® Corporation for use with the Windows® graphical user interface. These fonts can be used for both the screen display and printing thereby eliminating the need to have two font files for each typeface.
  • Typeface: Often named after a designer, a typeface or face is an interpretation of a character set that shares a similar appearance and design. The character set includes letters, numbers, punctuation, and symbols. On computers, typeface is often used interchangeably with the term font.
  • Typography: Typography is the study and process of typefaces; how to select, size, arrange, and use them in general. In today’s terms typography includes computer display and output.
  • Uppercase: The large, capital letters of typeface.
  • WYSIWYG: What you see is what you get. Refers to a relatively accurate screen representation of the final printer output.

Note: This document originally appeared in 2001 – and yet to be updated.
Dean Donaldson.