Hey Alfio, First, I'll say this is an improvement over the last portrait you painted. The edges between your values are softer and look more natural. Now some suggestions. I noticed that your drawing is not tilted the same as your reference. Look at the angle of the eyes, that always helps you to see what the tilt of the head is. It also looks like you are not evaluating the light/ shadow shapes in the reference quite right. It looks like you made up the shadows from your imagination instead of the reference. For example, look at the shadow you put on the side of the nose facing us, that shadow does not exist in the reference, it's actually a light shape. I did a quick and dirty paint over to show you some of what I mean. Look at the differences between it and yours, and you should see what I mean. I hope this helps you, and again, nice improvement :)