The first sketch I tried with the red and blue pencils was this light one of a baby I'd been holding the day before.  Hmm.. Cutting out colors makes it a bit easier to determine where the shadows are...

Next I tried sketching from an old photo of my husband and me that was on my desk.  We don't look this young anymore.

And finally I got bolder with the use of the color and tried my hand at with a photo of my grandson. 

Right now I'm using one blue pencil and one red pencil to sketch these but I can see how it would be nice to have one of those red/blue pencils where you can just use one of the other.  I really enjoyed this class though I maybe I should take a class on how to draw (even loosely) faces.

Adding...

I'm adding one more photo (the next day) that I did to see if I could sketch scenery with red and blue pencils.  It worked!