Quote Originally Posted by gmikol View Post
Allowing it to warm up fully (10-30 mins.) will not hurt it from an accuracy standpoint, and probably help it, longer than that, you need to balance that against lamp hours. Leaving it on all day for one set of measurements probably doesn't make sense. The replacement lamp for my Xrite costs almost $100. Some densitometers bulbs may only cost $5 or 6.

Hope that helps...

--Greg
My X-Rite 801 doesn't turn the light on until it does the measurement so I could leave it on all day without hurting the lamp. It does seem to drift a bit so I calibrate it before use. The calibration routine is pretty much automated and can be done in a minute.