bitmap files, vector files and tracing tutorial, page 1, 2, 3 & 4

This page talks about the most common problem encountered when trying to make decals and signs. For most people, trying to understand why a small image cannot be 'blown up' is a little tricky. To help out, I've put these pages together and we'll use a fictional Company's logo to demonstrate.

A typical example is that a client - in this case, Emm, has a logo that she uses on her website, Word documents - perhaps even a little desktop publishing. She'd like to have a banner made up for a tradeshow, as well as having the logo on the rear window of her vehicle. This is the logo in exactly the size that she currently uses:

 

The file is 150 pixels by 68 pixels at a resolution of 72 dots per inch. It looks fine on screen and if you print this page - it would like fine there also. The question then becomes:

Why isn't this file suitable for use in signage?

The answer lies in that the file format (.gif) is a bitmap file. By that, I mean that it is a collection of dots arranged in close formation and presented so that they look like recognizable shapes and letters. There is nothing in the file that says 'this is a 'g' and this is an 'r'. It's just dots, like a photo in a newspaper.

The image on the right shows what happens to the dots if the file were scaled up to make the logo 12" tall - I've just shown a section, otherwise it would be too large for your screen. As you can see, each of those dots - which are square - has been scaled up and the result isn't very pleasing at all. It is no different than if you put the small logo onto a copier and 'blew it up'. Eventually, it would start to look very 'jaggie'.

Clearly, no-one would ever want their logo to look like this. So what can be done?

Some improvement is achieved if 'anti-aliasing' is used. This is where software takes a look at the neighboring dots when it does the enlarging and blends between them to soften the look. Any idiot can use software to scale up an image like this, there is no skill involved - it is, however, cheap. It is an improvement over the first example, but it still lacks clarity.

I won't produce output that looks like this. It looks terrible and people will ask 'Hey, who did your awful graphic', and you'll tell them not admiting that you cheaped out. I don't need that bad press. I will happily print bitmaps - don't get me wrong, but they have to be appropriate in quality for the project in hand, or have me trace them.

tracing discussed on page 2