Define offset lithography
What is it and why should I care?
Web Offset Litho Printing is one of the most popular technologies for printing commercial print in the world. It was developed as a way to print from reels of paper (instead of sheets), meaning the paper can run through the press more quickly. It has the added bonus of folding down the printed paper into finished sections in a single pass through the press. The benefit is that you are cutting out the cost of folding the sheets off line (away from the press) and also saving time by printing faster on a wide range of medium to longer run print jobs.
Why should you care? Well if you are looking to print a larger run of brochures, catalogues, magazines, then you might be wasting money if you print using any other method.
How could I be wasting money?
It’s something we’re always going on about here in the Yellow Shed. But one of the most crucial elements to printing any project is making sure you go to the right sort of printer for your job. If you go to the wrong printer, or rather, if you put your job on the wrong printing press, then it’ll be a less efficient way to print your job. And that means potentially a slower delivery, a reduced quality and, importantly, a higher cost.
OK, I’m convinced. Give me some more info.
It starts with the specifying of your job. It’s important to fully detail every aspect of the job. The tighter you can specify the printing, the more accurate it’s possible to define which press type is right for your particular job. You still need the experience of working with a wide variety of presses to be able to determine precisely which press suits your job, but tapping into that expertise will help you get the optimum result. And that means you’ll get the best quality job for the lowest cost.
So is my job suitable for Web Offset Litho Printing?
Litho refers to lithographic – that’s a process whereby hydrophobic ink (meaning the ink won’t mix with water) is attracted to a printing plate that carries the image of your artwork. This ink is then transferred to a printing blanket and it’s that blanket, carrying the ink, that transfers the artwork image onto the paper. With Web Offset Litho printing, the paper is fed into the press in a continuous web of paper from a reel.
Once printed, the paper is either folded into sections or if the press has a sheeting unit attached (not all of them do) they can be cut into manageable sheets. Sheeting is found mostly on the smaller web offset presses and used (mostly) when the paper weight is too high for the in-line folder.
And before someone comes back at me, there are exceptions to the web/sheet fed rule – you can get sheet-fed presses that use reels of paper (cut-star) but these still run a lot slower than web offset presses.
So for longer runs of print (more copies) and higher pagination (more pages) web offset litho printing can be a more economic process. Will your job be most suitable to this sort of printing process? We’d have to check out your specification to tell you for sure.
There are gazillions of variations on print specifications that determine which sort of press is best suited for your job. Elements like product type, quantity, finishing, number of colours, paper type, all play their part so It’s important to get sound independent advice on which process is suitable for your project.
What’re the benefits of Web Offset Litho Printing over other Printing Processes?
- The turnaround time of a project is usually quicker for larger sized jobs.
- It’s typically cheaper for jobs of over 10-20, 000 impressions.
- It gives consistently high quality results