Screen printing frames are available in wood or aluminum with different mesh sizes. Mesh size is measured by how many threads of mesh there are crossing per inch. The higher the mesh count, the finer the threads and holes in the screen. Which mesh count should you use? This depends on how detailed your image is and the thickness of the ink you are using. If you have an image with extremely high detail, a lower mesh screen won't hold the high detail. The fine lines or dots in your image will simply fall through the larger holes in the mesh, degrading the level of detail. If you are using a thinner ink, the ink will flood through the larger holes and soak onto a shirt or substrate making your image blurry as the ink bleeds. On the other hand, if you are printing with a thicker ink (such as white) through too high of a mesh screen, the ink will have harder time passing through the mesh. If you are incorporating many different ink colors into a print, you may need multiple screens with different mesh counts.