How to Calibrate the 361T for DensityDensity Calibration - 361T
Please note that there are several calibration options for the 361T. This page outlines the 'long' calibration routine which views and allows edits (as required) of the stored reference data. To perform a full instrument calibration proceed as follows:
Locate the 5-step calibration standard (Pn 361-68). Notice that step #4 is marked with the word "CAL". Also note that the ANSI traceable values for this step are hand-written below each film target.
The word "CAL" is also printed on the 361T. It is located between the "FUNCTION" and "COLOR" keys at the rear of the measurement arm. To begin the calibration routine, press both of these keys at the same time - then release.
The prompt "N Dcal Y" will appear. The "N" reply is associated with the "FUNCTION" key and the "Y" reply with the "ZERO" key (notice the words silk-screened beneath the densitometer's display panel).
Answer "Y" to the above prompt by pressing the "ZERO" key.
The prompt "N Qcal Y" will appear. "Qcal" is short for Quick CalTM. We do not want the Quick Cal routine. To continue then, press the "FUNCTION" key to answer "N".
The densitometer will briefly display "SET HI"' and will then show the number currently programmed for the "CAL" step. It begins with the ORTHO (o) channel.
Press and hold the "ZERO" key down then press the "COLOR" key to raise the value, or press the "FUNCTION" key to lower the value until the value in the display matches the ORTHO value printed on the calibration standard.
When the number matches, release the "ZERO" key then press the "COLOR" key one time to advance the calibration routine to the next step.
The densitometer will now display the valued stored in the UV channel. Press and hold the "ZERO" key down then press the "COLOR" key to raise the value, or press the "FUNCTION" key to lower the value until the value in the display matches the UV value printed on the calibration standard.
When the number matches, release the "ZERO" key then press the "COLOR" key again to advance to the next step.
The densitometer will now prompt "READ AIR". Press the "READ" button down firmly and hold until a number is shown on the display panel. Note: nothing is placed under the reading head for this reading.
When you release the button the densitometer will display "READ HI". Locate the calibration standard film and place it beneath the reading head. Ensure that the "CAL" step is centered beneath the instrument's aperture.
Again press the "READ" button firmly and wait until a number is displayed. The number it displays will be the value you programmed into it from the steps above.
To verify calibration was done successfully; read each step of the calibration standard film for both Ortho and UV and verify the densitometer readings with the values printed on the calibration standard film. You should be within +/- .02D. If not; your densitometer's lamp may be bad or the densitometer many need service.
That's it! The densitometer is now properly calibrated for both the Orthochromatic and the Ultra Violet measurement channels.