Discuss the various t-shirt fulfillment services in this general fulfillment forum. Newer companies like RedBubble, etc can be discussed in this main forum.
Companies that have been around 2+ years (CafePress.com, Zazzle.com, Spreadshirt.com, PrintMojo.com, PrintFection, etc), may have their own separate subforums below (as demand permits).
I'm talking about places like cafepress, customink---sites that give you a template of a blank t-shirt (you pick the color you like) and then you put your design on it and they print it for you.
If your primary concern is t-shirt colours, then you might want to consider using a service that can offer American Apparel tees (probably most of them) since they have a particularly nice colour range. If you're after a more basic tee (and simpler shades) Gildan also have a good colour range.
I think most fulfillment sites offer multiple brands, and normally cover these majors.
Oh, and as for colour fidelity... no, it won't be exact. If you want exact you'll need to get them screenprinted by someone who will match Pantone colours. Otherwise, it will be a (close) approximation.
I'm talking about places like cafepress, customink---sites that give you a template of a blank t-shirt (you pick the color you like) and then you put your design on it and they print it for you.
oh righto not sure but i found ur better off emailing them if its something out of the ordinary and they will do custom work for you
Custom T-Shirt Sites 
