From the DCU blog:

STEEL #1, the first part of the REIGN OF DOOMSDAY storyline, has sold out and gone back for a second printing, this time with a blood-red cover. Foreboding, right? Check it out below.

Related posts:

1. 27 #2 Sells Out and Heads Back to Press for Second Printing
2. Kick Ass 2 #1 Sells Out, Returns with Back-to-Back Second and Third Printings!
3. Chew #13 Sells Out and Goes back for Seconds!
4. Detective Comics #871 Sells Out and Goes Back for a Second Printing
5. Millar and McNiven’s Nemesis Goes Back to Press Again!