Offset printing is a popular printing technique in which the print design is initially printed on a rubber cylinder and then transferred to the product (such as glass bottle or candle jar).
This method allows large quantities to be printed cost effectively and produces high quality, consistent results.
What is Offset Printing? Definition –
Offset printing, also referred to as offset lithography, is a method of mass-production printing. The main cost is involved in the setup of machinery. You’ll often find that the more you have, the cheaper each print will be.
The method is having the imagine transferred through blanket cylinders and rollers to create a crisp image.
History and Development of Offset Printing
In the 18th Century, when looking for a cost-effective method to copy sheets of music, Johann Alois Senefelder invented lithography printing. Using high-pressure forms of limestone, he covered the areas which need to be printed with a fatty printing-ink and other areas with slightly acidic solution with polysaccharide (gum arabic) in the smooth stone surface. He then moistened it with water, leaving no ink in the freshly etched areas. This was a remarkable discovery and the development was a milestone in the concept of flat printing.
Both American Ira Washington Rubel and the German immigrant Caspar Hermann developed prototypes of offset printing machines in around 1904. Their machines mirrored the indirect printing with a blanket cylinder made from rubber to print onto paper. The process was realised to the public in 1912 in Leipzig.
Process of Offset Printing
It all starts with the pre-press stage where the image is broken down digitally on a computer when each colour is separated into a different layer.
Each image is lasered onto an aluminium coated plate leaving an imprint of each separate colour layer. Which is then loaded onto a roller where the non-image is dampened with water followed by being pressed into a vegetable oil-based ink. The ink travels through several rollers before going onto the main roller on one side, which contains the image along with a blanket offset cylinder. The blanket cylinder is there to ensure a clearer and sharper image.
The first part of the journey is where the image will then go down the line and pass through several rollers, each covered with different colour ink, layering to create the images.
Once the piece has has been printed, a transparent powder is sprinkled on top to allow the ink to dry without transferring.
How does Offset Printing Differ to Other Printing Techniques?
The art of offset printing is that the ink doesn’t get directly applied to the paper by a printing plate, unlike digital printing it is rolled from the plate to the surface. There are a total of four separate plates as each of the four colours are printed separately – cyan, magenta, yellow and black .
Offset printing is done between an aluminium covered plate and a blanket cylinder rather than using multiple colours at the same time digitally to create a more high-quality image.
Offset Printing for Glass Fragrance Bottles & Candle Jars
Glass packaging can be decorated using the offset print method to brand with a logo or design. This process provides an effective method for a high-speed printing of a multi-coloured line for large quantities of glass bottles.
Offset printing delivers a constant print and is often chosen for products like perfume atomisers and other glass containers.