Well, "yes" and "no." Here's what you can, and can't do.

Unfortunately, there is no global way in the Presto Service to get printouts at more than 18 pts.

But, there is a very easy way to get any print size you want, and that is by using Presto's PDF feature (detailed here: http://www.prestoplace.com/blog/entry/10147/NEWSFLASH--Presto-now-supports-PDF/ )

All you have to do is to learn how to convert documents to PDF. This is built-in to all programs on the Macintosh and is easily added to Windows machines (but you'll have to investigate what to buy or download for free yourself -- check out Adobe.com or other free PDF creators for Windows).

Once you know how to create PDFs by virtually "printing" them to your hard drive, then you can attach them to an email sent to your Grandmother's Presto Mail account. After the first email page, your enlarged PDF page will print out exactly as you have designed it. Best of all, you can use almost any program to create the PDF: Microsoft Word, Powerpoint, a text editor, your primary email client, etc.

Try it out first by experimenting and sending samples to yourself as PDF attachments. This will show you how your Grandmother will receive the attached document. Please let me know if this works for you, or if you get stuck and I'll try and help further. 

Presto Insider: Peter Radsliff
CEO, Presto Services Inc.