It just kinda came together over time. Almost the entire costume was bought at different thrift stores, yard sales, and things that I found around the house. I think it adds to the mood of the whole outfit since it's assembled from pieces rather than being tailored for the occasion. I feel like it's pretty much what Rorschach would have done; unlike with Nite Owl II, he defined himself by his ends rather than his means.
The only thing I bought new was the hat, and that I had to special-order online (my head is too big for anything smaller than XL). Hope to get the official movie replica someday. The hatter that designed it sells them custom fitted from his store in Texas. The mask was a gift from my best friend as part of an old joke of sorts (I wore a Rorschach mask to a formal masquerade in 2009).
Been following you for a while myself after I saw your Silk Spectre II costume. Big fan of your work, so it means a lot to me that you commented!
On top of the costume, I had the changing thermochromatic mask, brought a can of beans with me for lunch, and stayed in character with the grizzly voice for most of the con. It was an absolute blast; can't wait to take it to my next con!
You're not the only one, apparently! Only worn this to one day of one con, and I've already gotten two on-the-spot marriage proposals out of it. Still need to think of an appropriate in-character response in case it happens again.