Most manga, comics, novels, and graphic novels are published by offset printing, which basically means that the files are sent to a printer who then turns on the press and bling, blam, boom, several hundred, if not thousands of copies are printed, bound, trimmed in a given print run.
The term 'offset' refers to the printing plates that are used to print books. A photo-sensitized metal or paper plate is exposed to the negative film of the image or text files, such that the text/images on the plate hold onto ink, while the non-sensitized areas repel ink. When the inked plate comes into contact with paper, the images/text are transferred to the paper. Repeat thousands of times until all of the pages of the book are printed.
For full color printing, the paper is run through a series of five inked plates. As each layer of color, yellow, blue (cyan), red (magenta) and black is printed and overlaid on each other on a sheet of paper, it results in a full-spectrum of printed colors.
Color printing can be tricky, because if the balance of any given color is off or is not aligned correctly, then the whole image will look irregular; either the colors will look funny, or it will look blurry. In many cases, publishers will request a press check, or a small trial run of a printed book, which they can then review. Based on the results of the press check, publishers can then ask the printer to make adjustments before committing to printing the entire print run.
There are several advantages and disadvantages to offset printing:
- Lower cost per book - With offset printing, the cost per book is less when more copies are printed. That's why it's in the publisher's best interest to choose the right amount to print that gives them a reasonable cost per book, that doesn't result in them printing too many books that they can never sell.
- Full-color pages and special printing effects - Offset printing also allows for things like color page inserts, fold-out pages, embossed and foil-stamped covers, French fold covers and other schmancy features that you love.
- More lead time required - Offset printing requires significant lead-time, because the printing time must be scheduled with the printer, the colors and print quality must be checked before the publisher OK's a print run to be started, and after it's printed, it must be shipped to the publisher / distributors. If the printing was done overseas, then you have to allow for shipping via boat (cheaper, but slower) or air (faster, but more expensive), and customs inspections, payment of duties and taxes, etc.
- Not cost-effective for smaller runs of books - Offset printing is not that precise - once you turn on a printing press, several hundred pages / books will be spit out in an instant. This is why printing a single book, or even runs less than 100 copies is usually not possible. Or if it is, the cost per book is very high, because setting up the press and plates for each print run requires a lot of time and money to pay for supplies, press technicians, and so on. For smaller print runs, print on demand (POD) publishing is a more cost-effective solution.