Accuracy, dependability and the ability to repeat tests with the same results are the most important functions of a lab spectrophotometer. Since this equipment is likely to be used frequently in most labs it is essential that the data and information be accurate with each and every test run. This means that wavelength accuracy and wavelength repeatability have to be very specific, a good number is plus or minus two nanometers for most types of lab work.

The stray light within the laboratory spectrophotometer should be rated at less that zero point three percent to ensure that readings are consistent and repeatable regardless of the day or time when the reading and test was originally completed. Since most lab spectrophotometers will use a standard tungsten halogen lamp this is also an important consideration. This light source is highly dependable and consistent, again leading to repeatable readings without any concerns of deviations on tests.