I work with a lot of old blueprints that generally get scanned in in grayscale in 400 DPI or higher. I generally have no problem reducing noise in them, but I recently received a set that is in .tif format as a bitmap. It is pure black and white, no greayscale at all, so "reduce noise" and "leveling layers" are useless. Every pixel is either black or white and there is no way for photoshop to differentiate. I am by no means an expert on photoshop so I could very much use your help here.
I've included a small sample, because the original image is over 5 mb's and I don't have permission to share them. So keep in mind it's been re-saved by photoshop.