I used to work in offset printing, and there were a couple of TV procedurals that completely missed the mark in how printing is done.
In NCIS:LA, Callen goes undercover as a counterfeiter. Hetty gives him an operating manual to memorize overnight. He meets up with the counterfeit ring and operates a press for the very first time and seemingly creates unerring duplicates in one pass. No. Hell fucking no. A printing press requires a lot of hands-on experience, knowledge of the intricate moving parts, knowledge of the balance between ink and water, adjustments for the type of paper, humidity, and registration board, that comes with lots of hands-on practice. Moreover, it’s not just green ink. There’s other colors on money, and the serial numbers are all different. Making truly authentic-looking money requires a lot of passes through multiple machines. Even if you’re a genius and can memorize a 500-page manual overnight, memorizing and applying are two different things.
I will say the film To Live and Die in LA was much more accurate. I even recognized the machine they used. Hey, that’s a Multilith 1250!
In Sherlock, the detective is prowling through a suspect’s office and concludes the suspect is a scam artist, because the framed certificate on his wall was printed on 20 # paper. 20 # is the standard weight for copier paper, and generally heavier paper is used for certificates, but it’s not a universal standard. Plus, it’s hard to guess the paper weight just by looking at a framed certificate without taking it out and examining it. Even if the certificate is printed on cheaper paper, it’s not a smoking gun for determining a suspect is a scam artist. It could be a copy to keep the original preserved, or the issuers used a home PC & printer instead of spending money at a printing service.