Thanks for attaching an example image. That helps make the discussion more concrete and productive.
The first thing that I'll note is that the image does not have only the date on it, but also a textured carton with additional printing on top, a background, etc. We often forget how much noise our human visual system excludes automatically.
Tesseract is going to work on a bitonal image. Since you have more knowledge about the conditions the image was made under, the subject, etc, you can probably do a better job of converting to bitonal. For resolution, check the FAQ. There are some guidelines there about the height of characters, etc.
Good luck!
Tom