Developing printer drivers for high-resolution and photo-realistic printing on modern inkjet printers (e.g., by Epson, Canon and HP) is a very demanding task. While printer drivers for mainstream platforms are made available by the printer manufacturers the RISC OS platform has been left behind without being able to drive the most recent printers with satisfactory results.
Luckily, there is a very active group of people developing Linux drivers for
these printers: This is known as the 
Gimp-Print project. Gimp-Print
supports hundreds of printers and is constantly updated to support new printers
as they become available. There is an emphasis on Epson printers because Epson publish
their printer control codes (in contrast to other companies, e.g., Canon).
Gimp-Print for RISC OS is a RISC OS printer driver based on the Gimp-Print library. It can be used like any other printer driver to print from RISC OS applications (e.g., ArtWorks, OvationPro, Impression, PhotoDesk, Paint, Draw to name just a few).
These drivers support high-resolution printing with photo-real print quality and offer colour correction for different media types (plain paper, glossy photo-paper, overhead transparencies, etc.) as well as user-defined colour correction (brightness, contrast, saturation, density, gamma).