Really looking forward to this.

Back in the day, when artwork was done in black ink on a white board, a 'photo' was taken of it through a device called a line camera (literally, a camera for line art - art made of black lines.  Like a comic book page.)  This camera registered only the black ink on the board, and in solid tones.  It produced a piece of film at the desired reproduction size.  (If the original art was 11 x 17, for example, but it was going to be printed as a 5 x 8 page, it would do the reduction in camera.

The film produced was a simple sheet of mylar with an emulsion on it, that reproduced the image of the original art in reverse, as a film negative.  Where black ink would print, the mylar was clear.  Where the page would not receive ink, the mylar was black (from the emulsion).

(A similar process would be used to create the different sets of film needed for the other colours needed in the printing process to create the full colour image that would be finally printed.  Cyan (blue), Magenta (red), Yellow and Black.)

Film for each page in the comic would be arranged in a printing layout (multiple pages together on one sheet of paper which would be printed on both sides, then folded and trimmed to make the individual pages in the book) and used to create a printing plate.

A large printing plate would be put in a glass suction frame, and the piece of film for that colour ink (let's say this is to be the Black plate) would be laid on top of the plate, so that the photosensitive emulsion of the plate and the emulsion on the film were touching each other.  The glass frame would be closed and the suction would remove all air from between the plate and the film, so that when exposed to light an exact reversed reproduction of the film would be created on the printing plate.

The exposed plate would be developed just like the film, and put in the press. On its surface would be an area attractive to ink (where the image was exposed) and an area that would be attractive to water (which the ink would not adhere to).

In offset printing, the press would roll the ink and water onto the plate, then a rubber cylinder would pick up the ink from the plate (but not the water) and put it onto the paper.

The other colours would be printed the same way, then it would go to the bindery, then to the coven room where the satanic blessing would be put on each copy, then to the warehouse for shipping and delivery.

So.  The short version:  They used to use 'film' to print the artwork in comics.  Now the art comes in as a computer file that is imaged straight onto the plate via computer.  But in order to reprint 2112, the film would be needed, or a complete set of the original art and equipment and skills now considered to be outmoded and arcane (and perhaps not even available) would be necessary.

Clear as mud, right?

Now, would I be correct in thinking that the duo-tone on the original art technique that JB used on things like Namor would be achieved at the same stage as the photo of the line drawing? Since the duo-tone was a shade of gray, would the mylar have black where no ink should be, clear where the ink would go, and some kind of partial coating where the gray of the duo tone would show?

I'm no artist, so these things will never be of practical value to me, but I love nuts and bolts TV shows and DVD extras showing how things are done, and this forum is about as close as I can get for comics. Most other sites are just for entertainment, and their information/facts are usually wrong because the writers are people like me who know little, but instead of saying that they just write assumptions instead of asking. 

Thanks again, Al and Chris!