I agree that for exposing alternative processes where exposure times are usually over four-five minutes, there is no reason to be concerned about warm-up. It takes the spiral BLB tubes about one minute to warm up to full output. Using a light integrator to compare total output of radiation in one minute, counting warm-up, I measured 213 units. The output in the second and subsequent minutes was 240 units. In other words, the output is only about 10% more in the second minute with the bulb warmed up than in the first starting from cold. If your exposure time were two minutes, you would get a total of 453 units starting from scratch, and 480 if you started the exposure after one minute of warm-up.
Observe, however, that if you were using the spiral BLB tubes to expose AZO, where exposure times would be on the order of seconds, not minutes, the warm-up would be absolutley essential to consistent results.
Originally Posted by juan