I know everyone’s busy, and it’s a bit late for a submission, but here’s my sketch for the 2-week RETRO SCI-FI theme.
Used my trusty pencil and paper to get a sketchy look, then added some grays with ADOBE PHOTOSHOP OH WOW for some digital color sketch effect. Around 30 mins.
The Sketch Bin 
I like the effect the gray gives. Really makes the sketch’s compo pop. 🙂
Thanks Kat!