I’m preparing to build my own integration sphere (styrofoam ball 50 cm diameter) and I need a calibration point. Instead of buying expensive brand lights with more or less exact lumen info I intend to build my own cheap calibration light(s) and have them measured by other calibrated spheres later. Have some questions though:
1.) Do I need more than one calibration light – for instance with different reflector diameters, tints and output levels? I guess I need 2 tints since I won’t buy a professional luxmeter, and cheaper ones are said to react different on different tints. I also want to measure lights with high output (10000 lumens or more). Do I need a high output calibration light then?
2.) What other requirements are there? E. g., is it important to have flat bezels or black bezels (no stainless steel or bare aluminium).
3.) I intend to use a 105C or so with 6x or 4× 7135, in order to always maintain the same output with one cell. Is this stable?
Thanks in advance.