Offset printing, also called offset lithography, provides a cost-effective printing method for creating bulk and commercial printed materials. Due to its relatively low costs, offset printing quickly became one of the most popular printing methods for commercial applications. This method of printing is frequently used for products such as newspapers, magazines, brochures, stationery, and books. Offset printing creates a high-quality product at a low cost for any of your bulk printing needs.
What Is Offset Printing?
First used in 1875, offset printing provides a method of producing printed materials in bulk at an extremely high quality. It easily produces clean and sharp images onto almost any surface due to the way it uses a rubber blanket to transfer an image to the printing surface. The only printing methods that can produce a higher quality image are typically rotogravure or photogravure printing. However, when you need both a cost-effective and high-quality print, nothing beats offset printing.
How Does Offset Printing Work?
The process of offset printing uses a large printing plate to transfer an inked image onto a rubber blanket then to the printing surface. Since this process uses a rubber blanket, you can use offset printing to print an image onto almost any surface including paper, wood, metal, or leather. This rubber blanket also helps ensure a high-quality print because it can conform to the texture of the printing surface.
With the widespread use of offset printing for various applications, different variations of the process were developed to better suit each individual application. These variations include:
- Variable-Size Printing
- Keyless Offset
- Dry Offset Printing
Blanket-to-Blanket and Blanket-to-Steel
Blanket-to-Blanket can print on both sides of the printing surface at the same time. It uses two blanket cylinders and two plate cylinders per color printed with modern machines using four sets and eight sets. These modern machines allow for the printing of four colors to eight colors on both sides of the printing surface. This makes it more cost-effective for double-sided printing and speeds up the delivery time. It’s most commonly used for envelope printing when both sides of the envelope require information.
Blanket-to-Steel prints with a high level of precision, but can only print in a limited amount of colors. One blanket-to-steel can print one color with modern machines having 4 sets, 6 sets, or 8 sets. This allows for the printing of 4 colors, 6 colors, or 8 colors on both sides of the printing surface once. The precision of blanket-to-steel printing makes them useful for printing high-quality business forms, letters, and direct mail advertisements.
Variable-Size, Keyless, and Dry
Variable-Size Printing makes it easier to change the size of the print. It works by using removable sleeves for a quick adjustment. This allows for a cost-effective solution when printing with different repeat lengths instead of a standard length.
Keyless printing uses fresh ink on each revolution of the cylinder. With each revolution, the inking drum removes any residual ink from the cylinder to ensure a consistent print. It’s most commonly used for printing newspapers.
Dry printing transfers ink to a photopolymer relief plate before transferring the ink to the printing surface allowing for higher quality prints. This printing method is most commonly used on injection molded rigid plastic products such as buckets, tubs, cups, and flowerpots.
All of these variations produce extremely high-quality images at a relatively low cost. This makes offset printing an extremely popular choice for any bulk orders. However, smaller orders become more expensive due to the large initial costs of setting up the printing plate, rubber blanket, and inks.
The Advantages of Offset Printing
The primary advantage of offset printing over every other printing method is the exceptionally strong quality to cost ratio. Offset printing simply provides the highest value for any bulk print jobs. It offers an extremely high-quality image that very few other printing methods can match at a lower cost. The only situation when it does not provide the highest value is for small orders due to the high costs of setting up the machinery.
Another major advantage of offset printing is the speed that the process can complete large jobs. This process can produce large orders in short amounts of time due to the way it can control ink flow to minimize any interruptions. It also helps keep the quality extremely high by removing the possibility of low ink prints. With offset printing, every print looks exactly the same.
Offset Printing vs Digital Printing
Digital printing uses toner sitting directly on top of the paper instead of absorbing into the paper like the ink in offset printing. It uses a combination of Cyan, Magenta, Yellow, and Black dots to produce the image on the paper. This process is typically used for short-run jobs using a large format printer, high volume laser printer, or an inkjet printer.
Pros & Cons
Since digital printing uses dots of Cyan, Magenta, Yellow, and Black, it cannot reproduce true colors unless the colors are the same as these dots. It only attempts to replicate the colors by blending the dots in a small area. This reduces the overall quality of a digital print, as the colors can never truly match the intended print. With offset printing, you can accurately reproduce any color by blending the ink on the page. This yields a higher quality print than with digital printing.
When it comes to costs, offset printing becomes far less expensive than digital printing for larger order sizes. This is due to the lower cost of ink yet higher cost of setting up the machinery than with digital printing. Generally, any orders over 500 units become less expensive using offset printing than digital printing.
For turnaround times of your order, the differences between offset and digital printing are similar to the cost differences. For smaller orders, digital printing can offer a shorter turnaround time due to the low initial setup work. But, for any larger orders, offset printing becomes the faster option as the initial setup time becomes a smaller portion of the overall turnaround time.
To sum it up, if you either need an accurate replication of color for your prints or your order size is relatively large, offset printing offers the optimal solution. For smaller orders when quality is not as important, digital printing can be less expensive.
Sheet-Fed Offset Printing and Web Offset Printing
Sheet-fed offset printing uses a system to feed individual sheets of paper into the offset printer then prints the pages using the same mechanisms as a standard offset printer. To ensure each page is fed into the printer correctly, this process uses mechanical registration to relate each page to each other. This ensures each page is accurately reproduced with the exact same imagery. Some sheet-fed offset printers also use a perfecting press to allow for printing on both sides of the page at the same time. They can also use offset duplicators to produce fast reproductions of one-color or two-color copies in sizes up to 12 inches by 18 inches.
Web offset printing uses rolls, or webs, of paper supplied into the printer making it more cost-effective for extremely large order print jobs. This process is typically only used for orders of more than ten thousand impressions. They can print large orders at extremely fast rates with some reaching speeds of up to 3,000 feet of paper per minute. Some also have the ability to cut, perforate, and fold the paper to deliver an end product in the exact form it’s wanted.
There are two classes of web offset printers, coldset and heatset. These two classes of web offset printers differ in the way the ink dries on the page. Coldset printers allow the ink to dry by absorption into the page, while heatset printers use drying lamps or heaters to cure or set the ink onto the page.
Generally speaking, sheet-fed is used on smaller order sizes between 500 impressions and 30,000 impressions. Sheet-fed also produces generally higher quality prints since they produce on a smaller scale allowing for more accurate replications. The web is generally used for larger orders of over 30,000 impressions when quality is not as important. The most common use for the web is in the production of newspapers.
What Types of Items Are Printed Using Offset?
Offset printing is used for the printing of over half of all print jobs using printing plates. It’s most commonly used for any commercial or large run print jobs as that’s when the economy of scale starts to kick in. With its high initial setup work, the cost per print continuously reduces as the order size grows. This makes it an exceptional choice for any large orders whether they’re commercial or not.
The most common types of items printed using offset are books, catalogs, brochures, stationery, newspapers, direct mail advertising, and envelopes. These type of print jobs generally require a relatively high quality print at a low cost to offer the product at an affordable price. Offset printing perfectly fulfills this need by perfectly reproducing any colors at a high quality. Some offset printers can also cut, fold, and perforate the printed materials to deliver a complete end product. This makes it exceptionally good for newspapers and brochures that would otherwise require extensive labor to produce in the desired format. Any type of commercial print job that requires a low cost yet high-quality result generally uses offset printing.