How much light do you need on the canvas when you are painting?

[Margaret Port]

I'm curious to know what sort of lighting to use when working. I've recently painted a portrait (?) of a "bat plant" which has white petals over purple flowers, set against huge brilliant green glossy leaves. It looked excellent in my studio under my bright lights but when I put it in an exhibition it looked really dark and more diffucult to read. I am working with a skylight above the easel and directional spots in the room, some of which light the canvas. Due to creeping age, I now wear trifocals when I work, which creates glare as well. I find that the paint reflects light as well which also makes for problems.

Any advice gratefully considered.