Clients often ask us what files (images / logos) are acceptable to send so that their artwork will look sharp when printed. It is especially important to understand what is required when we are printing a large banner or poster since the image will be blown up and issues will be more noticeable.
The answer is as follows.
A vectorized EPS, AI, or PDF file that is created professionally is preferred. Any true vector art is usable. High-res images are usually acceptable, also. On the other hand, any low-res images (like images used for the web/raster) will be unacceptable for print.
A good rule of thumb is to check the file size. If the file size of your image or logo is around 10KB and is a PNG or JPG, it is probably ok for the web but not for print.
A tip we give our clients in order to see if a file is printable is to preview your file on your computer and zoom in to about 300 or 400 percent. If the image is blurry, chances are it will look that way when printed.
The image above  is what it looks like when you blow up pixelated (raster – jpeg) versus vector (pdf) art.
Make sure you use a professional commercial printing service when you want your material printed properly.
