gradient

In more detail

Two colours and a direction is the whole of it. Along a line, it runs from one edge of the shape to the other; around a point, it spreads out in rings from the middle. It may pass through three colours or five on the way, each given the share of the run it occupies.

Nothing between the two ends is stated. The file says where each named colour sits, and whatever draws the page works out every shade between them, as finely as the screen or the press it is drawing for.

What it does on a real document

The usual way to get one is to build it in a drawing program and drop the picture in. It looks right on a screen, and the fake shows the moment the page is printed or looked at closely — the bands appear, and the file has gained the weight of a photograph.

Described in the document instead, it is a handful of numbers, written once and painted wherever it is wanted: one used on twenty pages is described once. It can also be the colour something is filled with, so that the letters of a headline become windows onto a blend that runs across the whole word.

Where it comes from, and why

A press cannot fade an ink. It lays the colour down or it does not, so a fade on paper is thousands of dots growing and shrinking across the sheet, and the eye does the blending. A gradient written into a document states the intention instead of the dots, and leaves whatever prints it to work them out.

See it on a finished document

Gradients in a line and in a circle Text and shapes filled with a gradient