Chunky Peanut Butter Sketch

[ChunoKipor]

Here's that value study. It's a lot harder than I thought! I've done a great value portrait using colored charcoal before, and it's a lot different digitally. I'll add that old portrait once I've got it scanned, but for now, rough progress on this study.
The reference picture:
http://step-in-time-stock.deviantart.com...-205190187


And my work:


And just to see how this method worked with color:


Hopefully I'll be able to show further progress on this bit soon. Thanks for your time!