Lets you shade or colour the cells in the alignment environments such as \halign and LaTeX's tabular and array environments.

The colortbl or package is to be preferred today with LaTeX (it assures compatibility with the longtable package, which is no longer true with colortab); another modern option is the table-colouring option of the xcolor. however, colortab is still an adequate solution with Plain TeX.

The author is Timothy Van Zandt. The package is Copyright © 1993 Timothy Van Zandt.