The second type of common design format is Bitmap Design Programmes otherwise known as Paint Programmes.
Bitmap design programmes use tiny tiles to identify shapes called bits or pixels. The most popular Bitmap design graphics programmes are Photoshop, Paint, Gimpshop.
When you create a design in any of these programmes, the design is entirely made up of tiny tiles called bits or pixels similar to tiles in a giant mosaic. Where this gets confusing is that all graphics, both vector and bitmap are displayed in pixels on the computer screen you are looking at right now, usually at 72 ppi or pixels per inch.
Here is the crucial difference. Computer monitors are designed to display images at 72 ppi so the images look smooth, crisp & pleasing to the eye. To do that a computer monitor pixel consists of 3 sub pixels, a red, green & blue one which controlled by your computer light up differently to create the colours you're viewing right now.
When we screen print, we usually have to convert your image to individual spot colours with sharp edges. Most people want any curves on their fianl screen print to appear smooth. We have found that without the benefit of computer aided graphics to trick the eye, the minimum ppi we need the art to be is 300 ppi at the final t-shirt print size when we create the film positive. Any less than this and the curves appear as tiny steps or jaggered.
What we need from you. If you want to give us an image to screen print in a bitmap design format. Your art needs to be at minimum 300 ppi at the size you want the final screen print to be. As an example, if you give us a design which is 10 cm wide at 300 ppi but you want us to print your design at 20 cm wide, when we resize the image to 20 cm wide, the resolution will drop proportionally to 150 ppi and will not screen print clearly.
Common file formats for bitmap images are .jpg .jpeg .psd .gif .tiff
Having said all this, DON'T WORRY!
If you don't have exactly what we need, we can redraw your logo for you very inexpensively.