Portraiture: Similarity

 The past few days I have been working on portraiture. While I like making an accurate representation of a face, I have never spent much time with portraits. I preferred to study the figure, since I felt it was less stiff and posed, giving more emotion to the piece. I'm giving my self a little course in drawing here, making  a drawing a day! I plan to start with portraits, and work up to the figure, experimenting with different media as I go along  to refresh my repertoire.
This drawing began as I searched my computer for photographs to turn into portraits. I wanted to start with black and white photographs, since the values are much more clear and easier to practice with. Before I began turning all of my photos black and white, I found this cell phone picture of a portrait of my mom. I decided it would make a good subject, and it would also be interesting to compare our features, since I am around the same age now. Here's the drawing in progress-- I am posting this to see what I might change in this drawing, because something is off and disrupting the similarity between drawing and photograph. I can't quite put my finger on it. Something about the scale of the eyes/nose to the overall facial shape? It looks like the whole face needs to be wider. Time to do some measuring. Maybe I'll begin anew.