Line Art Extraction in Photoshop

Line art seems to print better if in 1-bit (no anti-aliasing). I discovered this during my various boardgame projects where often the reference scan was too low resolution and blurry for print. What I used to do then was to scale up to 500 ppi, sharpening, then go straight to threshold to produce a black/white image (probably a spaceship silhouette & stat text). But this didn't work well when the lines crossed over multiple colours. I used to remove those using various kind of slow methods, but today I discovered that Image/ Adjustments/ Black and White is quite handy. Just slide up a colour to lighten it.

There's some "blobbing" of the lines still after thresholding, but it can be cleaned up. I've tried some auto-vectorizers, but they can blob up intersections as well, and I don't like working with vectors (also don't have working software atm). Cleaning up pixels works well enough. Sometimes the blobbing/bleeding and defects are there in the original so I keep it for authenticity and charm. At print scale it's not that noticeable anyways.

Also attaching some '80s stickers I cleaned up (500ppi 18x18cm). Well, some of it was never sticker art, but I'm making it so. I'll try printing these on adhesive paper, then stick on clear adhesive plastic. Unsure if hand-cut circles will look any good but we'll see. 

Edit: I've added a few more extracted from ancient issues of White Dwarf, and then did some test prints. These stickers are all I have, and not nearly enough to cover my black slab laptops. The sizes are too even so it looks rather boring and unfinished still. So, I'm gonna have to do a few big pieces... maybe text, like Quake, Amiga, NIN logos. And maybe that sexy tall Centipede arcade side art with the mushrooms. And then a few small ones (stars, little skulls) as well for additional noise and space fill.

Edit II: Okay, I've made a bunch more, will test print and see how they come out (sheets are now 18x25cm). It's quite a bit of work to scissor these out. I've made bleed borders so inexact cuts won't show paper white. I fixed a little colour bucket issue on the Little Twin Star character. Found a nice hi-res Samus on Nintendo's twitter but I've yet to fill up the first sheet. I'm sure eventually some ideas will pop up. Will return with pics once I've applied these on my laptops. This is very nostalgia indulgent, but I had fun doing it. I'd rather have stickers like these than random promotional stuff. 

Sneak Edit: I've added some photos of the now very cluttered laptops. I think I'd be ashamed to go out in public with these. The apple was very nearly the same size as the one on the Mac Mini, it turns out. My printer isn't very good, but these looks about on par with old 4 colour stickers... colour plate misalignment and all. 

Another way to remove the colours which is similar, is to convert to CMYK and disable the CMY channels, keeping the K. None of y methods deal with moiré and browns well though. (Included a scan of my DK Jr box with just K enabled.)