Artists often have difficulty in getting a like for like copy of their artwork produced. One of the reasons is the size of the file is just too small, imagine trying to produce a crisp finely detailed engraving from a worn and scratched metal plate, you cant just as you cant produce a good quality print from a digital file that is out of focus, too small or lacking detail and depth. Printers will complain that artists are under the impression that any problems with their digital file can be resolved using Photoshop. Photoshop includes a number of features that help sharpen images, but not to the level required for fine art print work. It pays to have your work professionally photographed, however for many artists this is just one more added expense so the golden rule is to make sure your digital file contains 300dpi (dots per inch) when sized to the physical dimensions of the finished print. For example if you wanted to create a printed image twice the size of the original you would need the artwork to be captured at 600dpi. Once the image has been photographed it is best to supply the image saved as a TIFF file, which means they do not degrade each time they are opened. If you save the image as a JPG it means the image is compressed then re-compressed each time it is saved which results in loss of data. However I know a lot of people only have their work saved in JPG format and printers will do their very best but the artists need to know and understand the quality may be good but perhaps not as good as it could have been.