Portable spectrophotometers have been developed with experience gained from producing portable densitometers and have proven to be practical instruments for measuring color in almost any application including graphic arts. The geometry allows for calculation of density and correlation to portable densitometers, while the sphere geometry is preferred in the package printing industry for measuring printing on metallized foil substrates. This paper provides a brief review of instrument design and operation. Considerations in optical geometry, wavelength discrimination and error compensation techniques required to produce a rugged reliable instrument are discussed. Instrument performance testing is discussed with emphasis on ensuring instrument repeatability and inter-instrument agreement. Proper care and maintenance for portable instruments are also discussed including field monitoring techniques for verifying long-term performance.