Open shapes can be a printer's nightmare. Please make sure that you are properly closing each shape as you're drawing. The standard shapes in vector software (squares, circles, etc) will automatically be closed for you, but you'll need to pay attention when you're drawing your own objects. Check your images carefully in outline (also called "preview" or "keyline") view to ensure that every shape is closed, with no breaks, holes or gaps in the outline.
Please note: Most transparency effects (transparent objects, glows, drop shadows, etc) aren't compatible with the AI8 EPS format. Saving a file with transparencies as an AI8 EPS can cause your shapes to break open and color fills to flatten and "rasterize". We ask that contributors avoid transparencies in their submissions to iStock
Example of closed shapes in outline view:
Example of open shapes in outline view: