The 391 calibrates itself each time power is applied to the unit. Owners may also force a calibration at any time during use. The densitometer is completely automatic in this action. In fact NO calibration media is shipped with the unit. There is however, a calibration certification strip available from X-Rite. This strip (P/N 381-25) is certified at X-Rite and individually marked with reference densities. To use a 381-25 for instrument verification proceed as follows:
Apply power to the densitometer; wait until its self test concludes.
Access the "Main Menu" via pressing the two right-hand keys at the same time.
Using the first key, press until you have reached "p2".
Next, press the "setup" key.
Finally, press the first key until you have reached "p3".
Press the key beneath the word "cal". Then press the "Read" key.
Insert the strip (P/N 381-25) and allow the densitometer to pull the media through.
After measurement is complete the unit will [a] process the data and [b] display the time and date.
Measured values may be viewed by using keys two and three to increment and decrement the step counter.
To end the process press the key beneath the word "Exit".
