Have you been to outdoor shows where an artist is painting people's portraits? They are set up with an easel, their paints or pens, and someone sits in the chair across for them for a bit to have their portrait done. That artist is an amazing artist -- but he still needs something in front of him to inspire him and get him going. Try painting a face from memory. It's tough. It's hard to get the proportions right, the expression just so. But try it again with a picture in front of you, and it's so much easier. In my face painting practice, I've used magazine pictures (usually ads; invest in a Vogue or other fashion magazine, and you'll have tons to choose from), other artists' books or blogs, and of course, the new standby, Pinterest.
As I've said earlier, these paintings are not to be sold. They are practice. So if I am inspired by an artist, or I outright copy that artist's picture, it's just for me to practice. I am publicly putting my paintings on my blog, but I will tell you if I've copied another artist for practice. I don't think that artist will think for a minute that I am profiting from his or her work.
This first one came from an artist's website. She's wearing a big hat. I don't know, I think mine kind of looks like hair. I think it's very Bride of Frankenstein-like. I like this next one because it wasn't as detailed as the ones I've done, and it didn't rely on hair for beauty or interest. I think it's someone wearing a hoodie. This also was inspired by another artist.