The pdf files we supplied are color separated into CMYK and plates made for each of the component colours. The plates are made direct from computer, in a process called CTP (Computer to Plate). Here is the cyan plate coming out of the machine:
The plates are metalic, and made by the CTP imaging device which leaves reverse imprint of each colour. One plate will print 4 pages in one go, and by folding and cutting, will form a signature of 8 pages, with both sides printed.
Each plate is then loaded in their Manroland Offset Press - the Roland 700 HiPrint...an impressive, industrial looking machine:
Printed using environmental friendly soy based pigment inks:
View of the offset machine from the other side of the machine, showing the loading of cut sheets:
The paper path, each plate is loaded into the machine, and colors printed in turn. Note from dark (black background) to light (yellow foreground) are laid on the paper. The first module is a coating module, which in the case of my book is not used.
The printer lays inks in dots, and each of the four colours are printed offset an an angle to each other...hence the name offset printer. The resulting image is a series of dots in each colour, interacting to give us almost all colours possible. It is important for perfect registration of each of the colours, and the dots are not visible. I inspected the print with a 5X loupe, where the small dots are barely visible at 200 screen line resolution.
And the pages coming off the press...
And goes into the inspection table for comparison to the proofs produced earlier, which I inspected:
And the pages laid out in a box, ready to go for trimming and binding.
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