Photoshop CS3 Photo Effects Cookbook

Recipe 1.6. The Pen Tool, Vectors, And Paths

We've already touched on vector shapes in the previous section, but it warrants a little more investigation. The vast majority of imagery in Photoshop is pixel-based. Every single digital camera image, scan, or brush stroke is made up of millions of individual pixels. Pixels exist with the sole aim of rendering your photographic images flawlessly, and can collectively create incredibly subtle gradations of color and tone. The one disadvantage of pixels is that they are completely dependent on resolution to maintain detail and sharpness. Owners of low resolution digital cameras will often be surprised and disappointed to discover that the images from the camera start to disintegrate when they attempt to print them larger than the image's optimum, resolution-dependent print size. Well, here lies the Achilles Heel of the pixel; there is only so far you can enlarge a pixel-based image before the very nature of the pixels themselves become frighteningly apparent and the image begins to disintegrate into tell-tale block of color.

Vector shapes, on the other hand, are not subject to such constraints, as they are not pixel-based. Vectors are made up of paths and are thus resolution independent. A vector will print with optimum sharpness at the size of a postage stamp, and yet can be scaled up to the size of a small building with no loss of quality or sharpness. This is the exact reason why text in Photoshop is handled as vector shapes, so the ...