"Normal" PowerPoints provide the most professional looking
presentation option. The "Transparencies" PowerPoints,
when printed on made-for-color transparencies using a high quality
color printer, are your next best option for professional quality.
If your circumstances require that you use black and white transparencies,
in the PowerPoint "Print" box, be sure that "Pure
Black and White" is checked under the "Color/grayscale"
section at the bottom of the Print box.