It may seem a little like overkill to spend two blogs talking about the fine art of giving pitches to choirs, but actually it is just this sort of attention to detail that makes one not only obsessive, but also a fine accompanist.
Therefore, a few more thoughts on last week's topic:
In a performance, one's role is generally restricted to playing the first chord of the piece, rolled bottom to top (bass, tenor, alto, soprano). In a rehearsal, the point is to give as much, and no more than, is needed. If the director is starting over again from the same spot, the choir may be able to remember their pitches and you won't have to remind them at all. Or, you may be able to get away by playing the chord all at once, not a note at a time. It saves time.
If one of the parts has a note that may be hard to find, I usually linger on that note a bit before proceeding to the top. Let's say its the tenor part. I would play bass...tenor....(slight pause)..alto..soprano.
I usually give the pitches fairly quietly, as it allows the director to interject something over the top, and it forces the choir to have to listen a bit harder than when you are basically shouting pitches at them.
Sometimes you not only want to give the opening pitch, but the next note they will have to sing, particularly is it is a difficult interval, or something that sounds difficult in context (in other words, it is simply a fifth, which seems easy until you put it with the altos, who are singing something that clashes violently with that pitch).
Think like a choir member. If I'd want to hear something to help me out I play it. If it seems easy enough that they don't really need the hand holding I don't play it.
A lot of these suggestions rely on judgement calls. If you have to discuss everything with the director it just kills time; therefore, as long as I am not getting dirty looks from that quarter I decide on how to give the pitches, beyond the following obvious cues from the director:
The words "pitches, please"
A look in my direction
Air pitch giving, in which the director mimics playing the notes in the air. If you get the timing right, it looks like magic.
After you've worked with a director for very long you develop a rehearsal rhythm, and you can generally tell what they want and when they want it, which is also a helpful time saver, particularly as there is an awful lot to communicate in a rehearsal and there are a surprising number of false assumptions one can make when attempting to communicate about anything, never mind when giving out musical information in a hurry.
One last thing: you'll note that none of this has anything to do with technical achievement on the piano. And yet it makes a huge difference. There are a lot of things that fall into this category. That is good news and bad news. The bad news is they don't teach this is school. The good news is that it is very simple, and yet it is something that has to be constantly honed and attended to. And, it is one more way to avoid boredom and have a grateful choir.