I have been insisting that my students attend John Singer Sargent: Portraits in Charcoal
at The Morgan Libarary and Musuem. Each time I attend it is an education. I have been four times in the opening week; the last time was simply to study variations and similarities in his rendering of noses. Next time it will be to look for variations in eye shapes. When I stop learning from my visits I will stop returning to look at the work. There is simply no danger that I will run out of tips and tricks and methods from this master. I can tell that my work has improved with each return visit. Do yourself a favor and go!
Of course if you can not attend we recommend purchasing the catalog, which is terrific, even though there is nothing like seeing an original drawing with your eyes.