They take several 10s of seconds to reach usable brightness....longer than tuble starters. No good for short spells of activity as they are only becomming usable when they are switched off. Hmmm, ma
Peter some do and some dont. I have found the Osram bad and the Philips best so far. There are a number of other things to think about too. One, in normal replacement for tungten Fil they do NOT last