Desktop publishing Overview | Resolution issues| Page description language | Font management | Paper sizes
Desktop publishing
Overview | Resolution issues|
Page description language | Font management | Paper sizes
| Since a screen and printer differ in their presentation of
your publication, you need to be aware of the differences to enable you to compensate. For example a screen represents a document with around 90 dots per inch (dpi) whereas a printer will print at between 300 an 600 dpi. |
The quality of your printed publication depends on the resolution you use. Resolution, measured in dots-per-inch (dpi), refers to the clarity and crispness of your work. As the number of dots-per-inch increases, text and scanned images appear sharper, photographs display more gray, or middle tones and screened backgrounds, or graduated fills, appear smooth rather than grainy.
| Printing text | The laser printer resolution of 300 dpi is adequate as well as cost effective for many newsletters, reports, bulletins, price sheets and many other documents. Imagesetters or high resolution lasers with 1270 or 2540 dpi are appropriate for many brochures, books, catalogues, technical manuals, magazines and annual reports. |
Although numerous file formats exist, the two basic categories of graphic files are vector graphics and bit-mapped images.
| Printing line art
|
Vector graphics Vector graphics are line art, or a series of connected lines, which are created by line-drawing programs. Vector graphics can be increased or decreased in size without loss of quality. CorelDRAW! And Freehand are examples of programs that create vector images. |
| Printing images
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Bit-mapped images A bit-map is a graphic made up of hundreds of coloured dots. Created by paint-type programs should be used at, or near, the original size. If you increase the bit-mapped image’s size too much, the pixels and therefore the images, begin to break-up (although this can, when done deliberately and not accidentally, create interesting effects). If the clip art’s size is reduced, the pixels used to construct the image run together, obscuring detail and darkening the image. Images created with Windows PaintBrush are examples of bit-mapped images. |
Sometimes the printer will run out memory and only print part of your document. One solution may be to reduce the resolution (ie DPI) under the print setup, however the quality will be reduced.
Page description language (PDL)
A page description language (PDL) is a language used to instruct a printer on how to format pages using codes that are independent of computer and printer type. The purpose of a PDL is to allow the interchange of fully-formatted documents between computers which use different operating systems and different printers.
The fonts that you use in a publication such as those created by PageMaker, will vary with the type of computer, printer and type management utility you use.
Screen fonts are available which make the text attractive and/or easy to read on screen, however the print quality may not be high.
Printer fonts, on the other hand, print smooth high quality text but the text may not appear on screen exactly as it will print.
TrueType fonts attempt to provide the best of both printer and screen fonts and display text as it will print
Printer versus screen resolution
Images are represented on screen by individual dots or "picture elements" called pixels. A pixel is the smallest unit on the screen that can be turned on and off or made different shades. The density of the dots – that is, the number of rows and columns of dots – determine the image’s clarity or resolution.
A typical screen may have 0.3 mm between pixels. This is equivalent to approximately 90 dpi. A typical laser prints at 300 or 600 dpi. This means the screen appearance may be different to the printed copy. A screen used with a dtp program will be larger and have higher resolution.
Postscript printers
PostScript is a Page Description Language (PDL), developed by Adobe Systems, which has emerged as a standard in the DTP field. PostScript makes it possible to tap a printing device’s highest resolution mode, however it requires more printer memory and is more expensive than a comparable non-PostScript printer.
PostScript printers come with built-in printer fonts (also called outline fonts). Printer fonts on your computer’s hard drive are called downloadable fonts. You can use downloadable fonts when you want to use a font that is not available on your printer.
Non-Postscript printers
Non PostScript printers, eg Laser do not produce as high quality printouts as PostScript printers, however they are convenient and cheaper.
TrueType fonts will improve the quality of print on a non-postscript printer. TrueType fonts are scalable, ie you can increase or decrease their size.
Transportability of files between computers
If you use TrueType fonts in a document, you can save or "embed" them in the document. That way, others can view, modify, and print the document with its original fonts – even if they haven’t installed the fonts on their computers.
Substitution fonts
When you print a publication that includes downloadable fonts, PageMaker sends the fonts to your printer as needed, provided they are installed on your computer’s hard drive. If PageMaker cannot find the printer font to download, PageMaker substitutes Courier for the missing font.
Postscript and TrueType fonts support transformations such as scaling, rotation, reflection and skewing of fonts. Other scalable fonts support limited manipulations such as scaling, but not rotation, reflection and skewing. If you transform a font that does not support transformations, PageMaker prints a low-resolution screen version of the font. Nonscalable fonts print only at predetermined sizes and cannot be transformed.
If you are not using TrueType fonts, it is recommended that you install a type manager on your system. Type managers vary, but most:
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