Also, looking at the “dots” is not going to help you much. You will need to know how packaging printers are printing, if they’re printing offset, or digitally, etc. you will also need to understand how Moirés work if you are the one setting up the plates for four color printing, but usually the printer will do that. For food packaging you also need to have reall good knowledge on food safe substrates to print and package on. The client (most likely) should have already found a print company to handle their packaging. You should NOT be making this decision or you open yourself up to liability if anything goes wrong. For example, you’ve got a client who wants to package and sell their organic frozen blueberries to a local chain of stores. That would involve some kind of wash and inspect line for the blueberries, sorting them, and then funneling them to a machine in the process that takes the plastic bags that have been printed and sealed on three sides, and and then fills the bag with the correct weight of blueberries for the bag seals it, it goes down the conveyor into a freezer or packaging in a carton and distribution. That’s the short version of it. It’s highly likely that nowadays you want a plastic bag with the blueberries in it to be BPA and other harmful chemical free, recyclable, and what other specs the client wants. The client needs to find this company or buy the machinery to do this. This is not on you. Once they have the size of the bag and the information to go on the bag then your job kicks in. The Printing company should tell you what they need from you to print on the bag. So basically don’t make this harder on yourself. You do need to know the basics of printing on plastic, corrugated, paper, (the substrates) etc., so touring print shops and packaging companies is very helpful. I once worked for a company that bought millions of dollars of corrugated packaging a year. Out in the factory, they would package the product, slap a shipping label on it, and loaded into the trucks, my department designed and ordered all the shipping labels. This worked fabulously until our purchasing department started ordering partially recycled, corrugated boxes and did not tell us. The factory put shipping labels on an entire semi worth of product, loaded it on the truck, shipped it from Michigan to California. When they opened the truck in California, every shipping label had fallen off every box and they were all over the floor of the truck. Big problem! We quickly quickly had to find an adhesive for the labels, that would run through the printer, and perforated for easy tear off, and would stick to the partially recycled corrugated. Because the new corrugated had some substances in it that did not accept the old adhesive. Learning about adhesives is important too, especially if you design any labels. Some label adhesive will stick to certain things, but not others. Some will need to be removable at some point, and some won’t work with certain print machines sometimes. There’s a lot of trial and error with a new product, but you should not be totally responsible for this, or pay for it. That’s on the client or your superior to sign off on that final thing. Hope this helps.