Working with Graphics

The Golden Rule when working with Graphics

Graphic Formats:

There are two major considerations when working with graphics:
(1) How good does it look:
 • On the screen
 • In print
(2) File Size

The tradeoff is sacrificing quality for a smaller file size. Different graphic formats provide different tradeoffs of quality vs. size.

Some terms you need to know:

Raster or bitmapped graphics are the most common type of graphic. The terms bitmap and raster are interchangeable. Digital cameras and screen captures are bitmap graphics. Each pixel is assigned. Scaling of bitmaps can be unpredictable and create fuzzy images.

Vector graphics use vectors to describe lines and areas that are filled in by the displaying program. Vector graphics usually resize easily but are not always supported in different applications. Most fonts are defined as vectors.

This article is about bitmapped graphics.

Lossy vs. lossless: Some graphics formats lose quality every time they are saved. They trade very good compression (smaller files size) for quality. They are called “lossy” as they lose quality to achieve better compression. Formats that do not lose quality and are referred to as “lossless”. They trade bigger file size for higher quality.

Resolution or Dots per Inch (DpI), also referred to as lines per inch (LpI) or pixels per inch. This is the resolution that a graphic will have when imported into a document. It greatly effects visual quality. Not all graphics formats support internal dpi. More on this later.