Creating Roller Banner artwork can seem daunting if you’re used to working in Photoshop. If you know the CS5 suite, and prefer photoshop, the basic principles are the same as setting up files in illustrator, however this will create a huge file, perhaps larger than is necessary.
What’s the difference between Photoshop and Illustrator? Well, Photoshop uses Pixel based data to create graphics, and Illustrator uses vector based data to generate the graphics.
Pixels are a fixed size and dimension. When resizing a pixel, it will be stretched to fit the given size, and therefore the dots will separate to expand and fill the gap. (see left) The more the pixel is stretched, the greater the gap between the dots, which results in what we know as “pixilation”. Below you will see an example of a piece of highly pixelated text, “4pp” (see Fig 1.)
Vectors are mathematically calculated lines that get filled in as required. Vectors are created using “paths” as outlines, and they get filled in by using various instructions and commands. This means that vector based images can be resized without distorting the pixels or dimension, and vectors retain all the qualities of the graphic however large you need to go. see Fig 2. for an example of the same text, but outlined.
Pixilation does not happen with vectors, at least not until the graphic is output to a file (ie. Saved as a pdf/jpg etc). Because Vectors are calculated mathematically by the software, the information that is required to save vectors is simple. The information required to memorise a pixel is much more complex. Thus when using vector artwork you could have a file as small as 10kb, and the same file in photoshop using pixels could be 10MB!
Understanding this difference between photoshop and illustrator will help when creating a large piece of artwork. The ideal way to design a roller banner, if you like to use photoshop to be creative, is to design your background and any creative pixel based artwork in PSD and place this into either Illustrator or Indesign as a background. Then use illustrator or Indesign to create any vector based layers that need adding, and this will give you a much smaller file size to output as a PDF. However none of the above is relevant unless you output the file (vector or otherwise) at low resolution… Always remember to save any illustration as a high quality pdf for the best results, only compressing anything above 300dpi.
When assessing your document for pixilation, zoom in as close as you can to any line. If you see jagged or blurry edges at anything below 150% zoom, then try outputting again at a higher dpi. If you see a straight line – even at 1000% zoom, that means it’s output as a vector, and is likely to get the best result in print.
Written by Joanne Serellis