Printing Press

I got to go to a printing press today. That was pretty exciting. I work for a news paper company now and as part of the job, I got a tour of the printing company they use to print their paper.

It was a pretty interesting experience. I learned a lot. They led us through the entire process they use. First they get PDF files (CMYK) uploaded to them via FTP or other means. Then these files get checked and post-processed if needed. From these files, they create aluminium master plates (big sheets of aluminium), which serve as master for the printing machines. Each sheet fits 8 pages of the paper. There is also a plate for each of the major colours.
After these plates are created, they are fitted onto the printing machines. For colour printing, there are four printing machines going on at the same time, feeding into each other to get the colours overlayed on top of each other to produce the final product. The way the printing press works (from what they explained to us) is that the aluminium plates, produced in the previous step, have special coating on them where colour is supposed to be printed. The machines then apply water and ink to that plate. The coating attracts the ink and then it's impressed on the running pages. Before they run the press in full speed, they do multiple slower runs to adjust alignment of the different colours and setup the right amount of ink on each page (there are a sequence of about 20 knobs along the length of the page to adjust that). Once the machine runs in full speed, it is running amazingly fast and they can print more than 16000 8-page sections per hour. For bigger papers, they queue a number of printing machines in such a way that all the necessary pages come together in the end, where a machine is cutting and folding them to the ready product. It is unbelievable how fast and exact the machines are doing their job. The final step of the process is to combine all the different sections, which is done by another set of folding/inserting machines and to package the papers for posting.

Now I know :)