This is info on "3M's" and how they were used in the comic book industry

You may know already that not all the colors on a printed comic book page are solid colors--some are Light (faces, light blue skies, etc.) and some are Medium, and some are Solid. To get Light, Medium and Solid colors, dots of color are printed further and further apart (look at a comic book through a magnifying glass). Your eye sees these dots as TONES. In the same way, the little dots are mixed on a page and your eye blends them together and sees different COLORS.

After I hand-colored a comic book, I showed it to the editor for his approval.  I then had to "hand code" the colors (writing in all the percentages of the colors as I showed them with my painted dyes). This 'hand coding" helped the separators when they were working on the book at the separating plant.  

The book was then sent to a separation house to create the different printing plates. The plates are created with a photographic process that includes using a metal or mesh screen to make the dot pattern on the plates. Heavy screens with smaller holes made lighter colors--and lighter screens with BIGGER holes meant more ink got through and made darker colors.

Just before the separation work was shipped off to the printers, a photographic copy of the comic was made. It was created on ACETATE, a type of plastic, and is typically called "3M's" (for "MINNESOTA METAL, MINERAL and MANUFACTURING CO".-the guys who developed plastics for printing and a lot of other industries).

BUT there's something special about a "3M". It looks like a paper-thin plastic sheet with the comic printed on it. However, if you lift the plastic up, you'll see there are SEVERAL sheets--each one represents a particular color printing plate. As I've discussed, there is RED, BLUE and YELLOW. A last one--the BLACK LINE--is added to represent the artist's inking work, as well as any printed text in the book. Sometimes a separation house would provide the black line sheet as a background to the other acetates--but the outcome is the same.

I've supplied some photos--up at the top of this guide you can see the three different color acetates laid out, then the black line page. See how there are solid color areas, and some areas are toned lighter (there's that "dot' thing again!--the spacing of the dots determines the intensity of color).

In the final picture, everything is put together.

Below, in this example of a single page--(usually the 3-M's are in "BIG "flats" of eight pages --just as they would be printed.) You can see how, one by one, as the acetates are laid out on top of the linework the colors mix--

Picture #1 is the black line work. Picture #2 is the magenta sheet, Picture # 3 is the YELLOW sheet,(going over the magenta sheet--yellow & magenta make red) Picture # 4 is the blue sheet that completes the picture. The final acetate reproduces the look of the finished color page.

There was only ONE "3-M" per issue. These were created in printing "flats" so they represented the metal (later plastic) printing press plate. Each "flat" had 8 comic book pages on it. There was also a single "3-M" for each comic book cover.

If you have a favorite comic book character, there may be a 3-M available for your book or character. As I mentioned, often the 3-m's were thrown out, so any that exist now are somewhat rare. And now that comic books are part of the computer era, 3-M's are no longer being produced.

I hope you found this info helpful. If you did--please click the 'yes" button at the bottom of the screen and also please read my other guides. Guides are a great way eBay people help each other to learn more about their favorite items!

--Adrienne Roy, color artist, DC Comics

I worked for DC Comics between 1977 and 1995

click here for a look at the 3-M's in Dragon Ladys Den and at my auctions!