I've used Service Point to produce large A1 size black and white prints onto either cartridge paper or transparent acetate plastic. They have a service desk so I've always gone in person with my files on a USB memory stick and just waited 10mins or so while they completed the order for me. I've been there a dozen times and never had a problem although the first time they did advise me to always go in the morning rather than the afternoon, because the machines heat up throughout the day and that's when problems tend to occur, particularly with acetate plastic. I only ever visit them in the morning. read more