Working with large files

For images/photographs, the rule of thumb is that any good image will work for anything, no matter the physical size. You can use the very same image for a magazine spread and a wall-sized banner. It will look equally good.

300 ppi is for books and magazines held right up to your nose. A billboard can be 10 ppi and look splendid.

Here's how that works:

Derek's point on image dimensions is well made. Don't work at too large a pixel size.

As far as scratch disk, it is common to see the scratch file running to 100s GB. Either make sure your scratch disk has sufficient space or add another disk to use as scratch.

Dave

Are you sure you have to work with very large files? People producing documents that are viewed from a distance, such as posters for example, imagine the resolution needs to be 300PPI, when a fraction of that would be satisfactory.