Many different things can affect how an instrument reads. Some instruments may have UV or polarization filters. Others differ in geometry.  Many may be configured to subtract paper or other constant value.  In addition there are several measurement standards in use globally: "Status T", "Status E", etc.  Unless each instrument is configured in exactly the same fashion, it is likely that measured values will differ.

Finally it is critical that each instrument be carefully calibrated according to its manufacturer's specifications.  Most instruments will be "married" to their calibration standards.  It is not appropriate to swap this media.  Doing so will certainly yield unexpected results.  Lastly, if a calibration is to properly set the "scale" of an instrument then the media must be meticulously clean and without physical damage.

X-Rite generally suggests an annual re-certification for its spectrally based measurement devices.  This annual visit to our certified color lab ensures that your investment is in good working order and satisfies ISO requirements.  Service contracts are available for most of our current instrument offerings.

More about contracts, click here.