Preparing Illustrations and Graphics

Use of Colour

PDF, like postscript, supports colour, therefore colour will be visible on the screen when viewing the proceedings. Authors should not forget however, that the proceedings may also be published in book form in black and white. The printer will render colours in greyscales and patterns and authors should inspect the black and white version of their printed paper to ensure that information is not lost due to the lack of colour.

Large Files

It can be very frustrating for readers to have their computer blocked whilst certain pages are laboriously painted on the screen and even more annoying for other users when a printer is blocked by a file which takes 30 minutes to print. Proceedings editors therefore have to devote a lot of time to ensure that the published files do not cause such problems. In the following sections some recommendations for authors to diagnose and cure problem files are presented.

Diagnostics

Typically, graphics files which have been generated from programs like tracking simulations, where the figure is made up from very large numbers of points or vectors cause problems - the PDF software is unable to compress the files and therefore when the page is displayed there are millions of elements to paint on the screen. There are two methods which authors can use to check if a file may be a problem: firstly, does the file take a very long time to print ? Secondly, if the PostScript file is displayed (using Ghostview or GhostScript on a PC, for example) does it take a long time to display ? The latter method can also be used to identify one figure from among several that is causing problems.

Remedies

Where the author has access to the software used to produce the figure, investigate if there are parameters which can be adjusted to reduce the number of points which are plotted (averaging, downsampling etc.). Alternatively, reduce the figure to a bitmapped image. This is a method which allows the final view of the figure to be essentially the same but which uses very much less space. There are a number of software packages which are commonly available which allow this kind of manipulation: Adobe Illustrator and Photoshop, for example. On UNIX systems one can use ImageMagic. With Windows7 one has the Snipping tool which can be used to convert part of a display to a bitmap and save the image as a PNG (the preferred format). The figure can be imported to these packages and then re-inserted into the document.