[pianotech] Stage Lighting & Tuning

[Alexander Lass]

List,

I am interested in your experiences/impressions/techniques in tuning  
for the concert stage or any situation where intense lighting is  
expected.  I attended Steve Brady's class at the convention this past  
week and all he said about the issue was, "if the lights are off when  
I get there, I tune in the dark.  If they're on, I tune with all the  
lights on.  Otherwise I'm chasing the pitch around the piano."  This  
makes sense but I'm wondering if there is anything one can do to  
compensate for the changes in pitch as the lights shine down.  My  
observations are as follows:

-Immediately after the lights go on there is a drop in pitch across  
the scale
-As time goes on, the treble (notably octaves 6 and 7) continues to  
drop in pitch
-After 5-10 minutes of exposure, the bass begins to come back to pitch  
and then beyond (even sharper)
-Only after 90 minutes or so does the pitch stabilize, leaving the  
piano with a very narrow tuning

Have others noticed similar changes (or different)?  If so, do you do  
anything about it?

Thanks in advance,

Alex Lass
Chicago