I read the blog of Scampix for getting your images printed and I would like to share my experience with printing images.
1. Make a research:Find two or three printing houses in your area that are offering quality service
2. Try:Go in each one of the houses and make demo copies of the same picture.Ask for specifics of the printing machine, like size of the paper, print area of the paper, maximum thickness of the paper, variety of papers, label of the printing machine and price of one copy, of course. Take notes.
Not every printer prints only up to A3 size. A3 size is 297 mm x 420 mm. Many machines can print bigger sizes - 320 x 450 mm, 330 x 470 mm etc. or even bigger if they use a color wide format printers. Many machines can also print on a variety of papers, except the standard 300 gsm (gramm /sq.m). 300 gsm is the paper usually used for printing business cards. Some printers can offer you granulated paper, or high-gloss paper, colored paper etc.
3. Compare results: Compare the prints and prices. Find the copy you like the most, with the most photo-realistic quality, or the biggest in paper size. Then make your choice
4.Negotiate:Return to the printing house and negotiate on prices. Present your self, explain you are a photographer and you are interested in using their service. Ask what price they give if you bring photos for print regularly or for more than one, or ten , or 20 copies of the same picture. Ask if they can give you samples of papers. Ask if they work with other photographers and if they offer other service.
5. Go ahead If you managed to negotiate good conditions - go ahead and take orders for prints.