What is Offset Printing? Behind the Scenes
Recently I took a trip to Capital Press to see the new Camille Co. candle packaging come off the press. I like to think of this trip as professional development. It is important for me to understand as much as I can about printing processes so I can appropriately set up artwork and inform clients of their finishing options.
What is offset printing?
Offset printing is different from digital printing. How? Digital printing machines use CMYK ink cartridges (cyan, magenta, yellow and K for black), or RGB if you're in the USA (red, green, black). Since the ink levels in the cartridges vary, so can the colours printed. For example, the pink you print today might vary from the pink you print next week.
Most digital machines will only feed paper up to SRA3 (450mm x 320mm) and to about 300gsm (gsm refers to the weight of the paper). Digital printing is now available in a B2 size machine (750mm x 530mm sheet size) however, there are currently very few of these size digital presses in the country, but they will one day be commonplace (hopefully). So if you're wanting to print on big, thick card or other specialty stock, it's likely it won't go through a digital printer. Offset printing allows for better colour control and thicker paper options. If you ever hear me refer to stock and wonder what I'm talking about, it's an industry term for varieties of paper (shiny, matte, thick, thin, coloured, recycled etc.).
Offset printing machines rely on plates for printing (like an ink and stamp system). Each colour needs a new plate and each colour is printed one layer at a time. Because plates have to be made there is a setup cost involved.
The ink that is used for an offset machine is like paint, it is mixed up and poured into the machine. The beauty of this is the printer operator can colour match and mix up the colour to your exact specifications, very handy for the sake of branding consistency. For example, the pink you print today will be the same as the pink you print next week.
Offset printing is recommended for large print runs. Because there is a setup cost involved, it isn't economical for short runs. When the numbers of copies increases, the setup cost is diluted and the cost per unit comes down.
When should I opt for Digital Printing?
• For small runs, such as promotional flyers, small business card runs, stickers etc.
• When your printing is smaller than SRA3 (450mm x 320mm) and under 300gsm
• When a bit of colour variation is ok (images print great digitally)
When should I opt for Offset printing?
• When you're wanting thousands of copies printed
• When you need to print on specialty stock paper thicker than 300gsm
• When what your printing is larger than SRA3 (450mm x 320mm) and you can't get to a B3 size digital machine
• When colour matching is crucial
Thanks for stopping by. If you have any questions, please do not hesitate to ask in the comments below. Thank you, Cheyney xx