first--what format is your 'image' tiff, jpeg, vector art created in illustrator, etc?
second--when you 'print out' your image--what are you printing it out to--inkjet, laser, imagesetter?
third--can you post a screenshot of your image, or the image itself?
IF you can answer these questions then it will be easier to assist you.
That's just how these things work: shaping everything from tiny little dots: