Our favorite image mode is a .tiff. Or send us vector art images (made in Illustrator or Freehand) instead of raster images (made in Photoshop). Jpeg files will create low-quality letterpress plates that will make you unhappy; its file format is best intended for the web. Files that end in .bmp can also give unwanted results by saving as the wrong size and are also lower quality.
Posted in: Designing for Letterpress, File Preparation, File Preparation