Most of our images are from old books and archives, created several hundreds of years ago. We do our best to reproduce the images in the best resolution possible. As the images are created with old techniques sometimes the prints can be easily mistaken for being "pixelated". They are not.
Lithography, among other techniques, is a chemical process that leaves the image with a smeared expression. This expression is exactly what makes the prints beautiful, and out of the ordinary.
Please, be aware that images from old books and archives are not vectorazed illustrations, and that a slight coarse and smeared expression can occur on the prints.