If a show is going to have color Playbills, it typically will start having them at the first preview and at least have them until opening night, so you are pretty much guaranteed a color Playbill during previews if the show has a color Playbill at all. (I find Playbill trivia kind of interesting, so if someone knows of an exception, please tell us about it!)
Some shows (like Wicked and The Lion King) will have color Playbills for years.
The only two shows I can think of that started in color, went to B&W, and then back to color are Spamalot and the LuPone Gypsy. I'm sure others can give more examples. There are also shows like Rent that had special color closing night Playbills after being in B&W for many years, but that's another category.
I do not know of any show that started in B&W and later switched to color. Again, if anyone knows of any exceptions, please tell us!
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