Purpose of Calibration
Calibration of sensors is essential for predictable and controllable printing. Without a way to calibrate the sensor, a system will give different readings whenever sensors are moved or realigned to the light source. This means that you never really know whether variations in light measurements are due to fluctuations in the light source or changes to the sensor positioning. The Light Counter LC2calibration process solves this problem.
If desired, then the system can be used out-of-the-box without calibration. This may be appropriate when using a light source that cannot be reliably calibrated, such as the sun, but is not recommended for artificial light sources.
Calibration is a one-time operation. It is not necessary to re-calibrate unless the light source, sensor or sensor position is changed.
The Calibration Process
- Set-up the light box and light source for normal printing
- Ensure all cables are properly attached
- Switch on the light integrator and allow it to complete its start-up routine
- Press and hold the CALIBRATE button until it the light integrator beeps. The display prompts to confirm calibration
- To cancel calibration, press any button other than CALIBRATE
- To start calibration, press and hold CALIBRATE again until it beeps
- If using the power controller, then the mains electricity supply to the light source will automatically be switched on. If not using the power controller, then do this manually
- The light integrator will wait until the light source is stable before calibrating. This may take several minutes with some light sources.
- Once the light source is stable, the light integrator will beep, and then start making calibration measurements for 60 seconds
- Once calibration is completed, the light integrator will beep, stop taking measurements, and return to the starting display. The new calibration value for this type of light (UV or visible) is displayed at the bottom of the screen
- If using the power controller, then the mains electricity supply to the light source will automatically be switched off once calibration is completed. If not using the power controller, then do this manually
The Calibration Value
Once calibrated the system stores a ‘calibration value’ for the light source. This is used to adjust light measurements so that one unit of exposure value is roughly one second of exposure time. It is shown on the bottom line of the light integrator display, but you can ignore this while printing.
Finding the Optimal Exposure
Once calibrated, one unit of exposure is approximately equal to one second of exposure. This helps to identify the initial exposure value to use when printing. For example, if your normal exposure time for a print is 3 minutes, then the exposure value for the calibrated Light Counter LC2system is going to be close to 180 (3 minutes x 60 = 180 seconds).
You may need to make a series of test prints before settling on the optimal exposure value. Use the normal exposure testing approach for your printing process.
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