Design & Layout...

The Digital Way!

A wide range of software applications support digital imaging. There are applications for producing digital drawings, modifying digital photographic images, working with typography, as well as page design, and combining elements into one composite image.

The graphics produced through the use of these applications can be divided into two primary groups or "graphic types," object oriented (vector) and bit-mapped (raster).

Object-oriented graphics are often used for line drawings, logos or any image that requires smooth, crisp edges. One of the benefits of object-oriented graphics is that they can be enlarged, reduced or distorted without loss of detail or sharpness.

Bit-mapped graphics are usually picture or photographic type images such as those captured using a scanner. Bit-mapped images are made by "mapping" the image to an imaginary grid created by the scanning software. Color or tint is applied to each square of the grid, producing an overall image. Unlike object-oriented graphics, bit-mapped graphics cannot be enlarged without affecting image quality. As the image increases in size, the squares of the grid increase in size, reducing clarity. It is important to plan for the final output size when scanning a bit-map graphic in order to have enough information, or detail, to meet the output requirements. Bit-mapped graphics are usually larger files than object-oriented graphic files, since more information is required to reproduce the image.

 
Image saved as bit-mapped image

While graphics files are divided into two types - object-oriented (vector) and bit-mapped (raster) - there are many "file formats" used to produce graphic images. Two widely used file formats are TIFF (Tagged Image File Format) and EPS (Encapsulated PostScript). TIFF files are usually bit-mapped, while object-oriented files tend to be EPS files. Different types of images, such as photographs, logos and line drawings can be imported into one assembly application for design and layout by using common file formats.

At the completion of the design and layout phase, all elements have been assembled into one file. This file may include both object-oriented and bit-mapped graphics saved in various file formats.

The file is now ready to be raster imaged (bit-mapped) based on the requirements of the selected large format output device. A grid is established based on the resolution of the output device. All elements in the file, regardless of type or format, are rasterized, (bit-mapped creation stage). This rasterized, or bit mapped image can now be can be reproduced by the chosen output device. To output Postscript or EPS files to a large format device, a Raster Image Processor (RIP) is required to interpret the data before sending it to the printer.

Terms to know:

Object-oriented image (vector) - a scalable image that can be enlarged or reduced without loss of detail.

Bit-mapped image (raster) - a graphic image formed by a grid of pixels or dots.

Rasterization - Changing vector-type image information to raster image information.

RIP (Raster Image Processing)

A process using mathematical algorithms to manipulate and print an image. Also, this software often includes "add-on" features, such as color-calibration software, various pattern selections, tools or a print-instruction screen.

Resolution - the number of pixels (picture elements) per unit of linear measurement (inch) on a computer monitor, or the number of dots per inch in output form.

It's time to... Produce the Image!