Hey Michael, I love these helmets, it's great that you are drawing it. @Moonless_Sky gave an accurate critique of the proportions of your drawing, and your self critique was also pretty correct. What I noticed is that it wasn't just the contrast in your values, but that you are not observing what the light is doing accurately. Notice how all the value in the upper part is all the same? This is not the case in the reference. That part of the helmet is blocking the light and is therefore darker in value. Also, if your going to work on toned paper, you will need to use a white chalk to show highlights. If you don't it makes your drawing look flat. I did a quick paint over to show you what I mean, I hope it helps :)

Hi Michael, looks great! I do think you could push the dark and light parts a lot more. The light on the "forehead" and the lower edge are not that clear on the drawing. The "jaw" of the helmet is a little bit too long. I drew it in the Reference for you, to illustrate the distances. Love the detail and how clean you drew it :) Great drawing! Keet up the good work :)