philo wrote:

The guy finally tested it and it did not do the job.


Yes, I used a big halogen lamp MANY years ago, and had VERY long exposure
times. A 400 W mercury vapor lamp with the outer glass shield removed did a
little better. Then, I finally switched to a different photoresist that was
more sensitive, and now use filtered black light tubes and have about 1
minute exposures. (This is for PC board resist, not silk screens, so their
emulsions might still need a lot more light.)

Jon