Preheat on dimmer packs with no preheat?

[David A]

Is it necessary to preheat lamps which are patched to dimmer packs with no preheat function built in? Perhaps by having the lamps on at a very low level? I'm using an analogue board at my school and it seems almost impossible to have a lantern on at such a low level that it's effect cannot be seen on stage, espcially during blackouts. Also, I'd like to know how nessacery preheating is? I've never preheated anything before... is it good practice?

the whole pre-heat saga has no basis in any factual study that I have seen.All thyristor dimmers leak a small current anyway.Running a quartz lamp at a low power should theoretically reduce lamp life because the quartz ion cycle is not activated.In practise I have run long seasons of rock musicals with constant flashing of lights without any noticeable increase in lamp loss.Nowdays with quartz globes 90% of lamps die while being focussed,this is where you need to be gentle and don't worry about the hokus pokus of pre-heating unless a proper scientific study is available.