Unless you have a special clean room lab like Intel and wear a body suit, chances are there will always be dust in your darkroom. I am trying to figure out what a normal level is. I think I am slowly winning the dust battle with my "Defender 4000 Air Cleaner". One of the ways I try to guage dust is to turn off all the lights and shine a flashlight through the air. I know that before I had the air filter, the flashlight beam showed a total dust blizzard. Now I still have very slight dust in the beam but nothing near as bad as before. I'm assuming this is just normal and there is no way to remove it all. I might also get a humidifier to further reduce it. If I go that route what is the max humidity level I should allow in the darkroom?
Out of curiosity, when you guys do the flashlight in the dark test what do you see? Thanks :)