What is a Calibration

Metrology Calibration

calibrating lcd monitor

Many people do a field comparison check of two meters, and call them “calibrated” if they give the same reading. This isn’t calibration. It can show you if there’s a problem, but it can’t show you which meter is right.  For an effective calibration, the calibration standard must be more accurate than the instrument under test. Do you use a clock that displays seconds?

Calibration typically requires a standard that has at least 10 times the accuracy of the instrument under test. Otherwise, you are calibrating within overlapping tolerances and the tolerances of your standard render an “in cal” instrument “out of cal” or vice-versa.

Calibration, in its purest sense, is the comparison of an instrument to a known standard. Proper calibration involves use of a NIST-traceable standard — one that has paperwork showing it compares correctly to a chain of standards going back to a master standard maintained by the National Institute of Standards and Technology.

In practice, calibration includes correction. Usually when you send an instrument for calibration, you authorize repair to bring the instrument back into calibration if it was “out of cal.”

If the report shows gross calibration errors, you may need to go back to the work you did with that instrument and take new measurements until no errors are evident. In nuclear safety-related work, you would have to redo all the measurements made since the previous calibration.

Calibrating pipettes

Calibrating pipettes is a necessary step to ensure the quality of lab results. However, as the use of mechanical action pipettes increases, there are more opportunities for problems to occur. Unlike the original glass pipettes, a mechanical pipette has many internal parts and if something fails internally, the user may not be able to detect it. An example of a silent failure is a corroded piston or leaking seal which may cause the pipette to deliver an incorrect volume. The user may not know that they are dispensing a volume that is off by a great margin. The more frequently you calibrate your pipette, the sooner you can detect a malfunction. This will maintain the integrity of your laboratory data and could reduce rework.

Calibrating Monitor

Calibrating LCD monitor make your monitor display images clearer and better. Monitor calibration can be very important if you’re a web designer, digital photographer, or graphic professional. You don’t want to spend hours choosing the perfect subtle color scheme only to see a miss-matched mess on someone else’s monitor or coming out of a printer. Here’s how to calibrate your monitor so that what you see is what you get.

Also check out our other guide on Calibration Thermometers tips and Calibration of Pipettes guide!