It's done when you abandon it
Some paintings are a gift, this one, torturous stroke after stroke, first drawn a month ago, and painted in sporadic marathon sessions since then. Burst a blood vessel in my eye on thurs, my eyes were so sore from painting for many hours, up close, step back, up close, and today, another marathon, all afternoon and evening. This detail was taken in artificial light and the colours were quite washed out so I deepened the tones in photoshop, and hopefully within the week I will get a chance to photograph the whole painting in daylight and post it.
I'm calling it quits on the painting! It's done when you abandon it.