Are you curious about what is offset in printing? If you have worked with a printing company before, you may have heard the term “offset printing.” It’s a common misconception that printing is done by simply clicking on a computer, but that’s not always the case. When it comes to printing a publication or packaging order, it takes more than just clicking the print button on a computer screen. To achieve the best, accurate colors and results, you must set up the machines and execute them properly, which takes a bit longer than your daily printing. This is where offset printing comes in.
Every magazine or box you receive is printed using offset printing, which ensures you get clear and vibrant print quality.
In this guide, we will discuss what offset printing is and how it works.
What is Offset Printing?
Offset printing is also known as lithography printing, offset lithography or litho-offset. This printing technique is the most popular printing technique in the packaging and printing press industry.
You might wonder about what offset printing is used for! Offset lithography is used to print larger runs of printing like magazines, manuals, books, letterheads, paper-based labels, and packaging.
It is slightly more expensive than other printing techniques, as it involves a fixed cost for setting up each job. Plus, each color is printed separately with this printing. The color spectrum that is widely used for offset printing is CMYK (Cyan, Magenta, Yellow, and Key (Black)).
How Does Offset Printing Work?
Offset printing is a multi-step process that uses etched metal plates, inks, water blankets, and an impression cylinder. The plates are used so that the ink can be printed only on the portion of the plate that contains the artwork. The ink on the plate is transferred through a rubber-wrapped water blanket. When the ink reaches the printed substrate, the cylinder rolls over the printed material.
To learn more about how offset printing works, let’s dive into the process of offset printing.
Step-By-Step Process of Offset Printing
There are a total of 4 steps that are involved in the offset printing process, such as:
Step 1 → Preparing
The very first step begins with the design preparation. Designers and operators have to prepare the image or artwork they want to print on the printing material. This process involves converting the color format from RGB to CMYK. Then, each version of the image is etched onto the plate, which is wrapped around the cylinder.
Step 2 → Feeding
After the designers and operators have calibrated the printers with the appropriate color profiles, they will begin with the offset printing.
The air jets in the offset printing machine push a single sheet at a time into the printer, automating the process. Once the paper enters the printer, it passes through the printing cylinder, where it receives the ink.
Please note: If you are using a modern offset digital printer, the machine will automatically detect if the paper is too thick to print, which means that the two papers are stuck, and it will shut down by itself.
Step 3 → Printing
The ink travels through rollers and cylinders before it gets printed on the paper. The printing process starts with the plate cylinders.
The dampening roller applies water to the part where there will be no image as the plate cylinder revolves, and the ink rollers will start applying ink to the parts where you want the image to be printed. Water is compulsory as it repels ink, allowing you a clean separation between colored and non-colored areas.
The ink goes from the spinning plate cylinder to a rubber-wrapped blanket cylinder, which is the only one that makes contact with the paper. Underneath, an impression cylinder pushes the paper up, locking the ink into place.
The paper will pass through a series of cylinders with different colored inks to form the final product.
Step 4 → Drying
After the final layer of ink is applied, the printed sheet moves to the stack at the end of the press. Since the ink’s still wet, the machine sprays a fine anti-set-off powder to keep pages from sticking together. This stops the ink from smudging once the print job is done.
Once the ink is dried, the operators will die-cut the unwanted sheets and send them for finishing and add-on options.
Types of Offset Printing
There are two distinct types of offset printing, each with its unique features. Here are the three types:
1. Web Offset Printing:
Web offset lithography is a typical offset printing machine used to print newspapers and magazines. In this, the printer prints on a long-run, continuous sheet of paper, which is then cut and separated once printed.
This type of printer is ideal for printing large quantities of orders, such as books, magazines, boxes, labels, custom boxes, or newspapers.
2. Sheet-Fed Offset Printing:
In sheet-fed offset printing, the paper is trimmed before the printer receives it. The printer has a feeding machine that pushes a single sheet of paper through the machine. A sheet-fed printer can produce from 12000 sheets to 24000 sheets per hour. This method is considered to be a quick printing option as compared to other alternatives.
Now that you know the types of offset printing and how it works, let’s examine how it differs from other printing methods.
Difference Between Offset, Digital, & Screen Printing
By now, you are fully aware of what offset printing is, but did you know that in the packaging industry, there are two more printing techniques that are used often? Digital Printing and Screen Printing.
Here are the key differences between offset printing, digital printing, and screen printing:
- Printing Process: Offset printing uses metal plates to transfer ink to a rubber blanket, which then presses the ink onto the paper. Digital printing skips the plates and applies ink directly from a digital file. Screen printing pushes ink through a mesh screen onto the surface, layer by layer.
- Quality: Offset printing gives sharp details and consistent colors, making it a top choice for high-end visuals. Digital printing offers decent quality but falls short of the precision of offset printing. Screen printing works great for bold and vibrant prints, especially with solid colors, but it’s not ideal for detailed designs.
- Cost: Offset printing becomes more affordable with larger print runs. Digital is better for small batches since it doesn’t require setup plates. Screen printing can become costly if the design incorporates multiple colors or intricate artwork.
- Turnaround Time: Digital printing is the quickest, as there’s no setup required. Offset printing takes more time due to plate making and press setup. Screen printing is faster than offset for small orders but slower than digital overall.
- Customization: Digital printing allows full customization, like changing names, barcodes, or text on each piece. Offset printing doesn’t support variable data. Screen printing can be customized to some extent, but each change needs a new screen or setup.
| Offset Printing | Digital Printing | Screen Printing | |
| Printing Process | Transfer ink with the help of a rubber blanket | Directly prints onto the paper | Pushes ink through a mesh screen to the printing surface. |
| Quality | Very high-quality printing with color consistency. | High-quality color printing, but not as good as offset | Offer bold and vibrant colors, but not great for detailed designs or graphics |
| Cost | Affordable for large orders | Cheaper for small printing batches | It is costly if the design has multiple colors |
| Turnaround Time | Longer setup time and ink drying time. | Quickest, as no process setup is required | Faster than offset for small orders but slower than digital printing |
| Customization | No variable printing | Fully customizable | It can be customized, but changes need a new screen and setup. |
Advantages & Disadvantages of Offset Printing
Every printing technique comes with its advantages and disadvantages, and so does offset printing.
Let’s take a deeper look at the advantages and disadvantages of offset printing!
Advantages
- Versatility: It can be used for different surfaces. It may include paper, plastic, and cardboard, which makes offset printing a versatile option for different types of packaging materials.
- High-Quality Images: This printing method helps to produce high-quality images and text with color accuracy. It offers sharpness, which makes it ideal for custom boxes and packaging projects.
- Cost-Effective: It’s a cost-effective method for a large packaging production.
- Consistency: Offset printing offers color accuracy and provides consistent results across large production runs. It makes sure that the final product meets the quality standards.
Disadvantages
- Time-Consuming: Printing with offset can be time-consuming, as it requires several steps and takes time to dry the ink.
- Not Ideal for Small Batches: Offset is not cost-effective for small batches, as the setup cost is higher compared to other options.
- Environmental Concerns: This printing method utilizes chemicals during the printing process, which may raise ecological concerns. It requires proper disposal to minimize the impact.
Is Offset Printing The Right Option For You?
The answer depends on whether you are ordering in bulk or in small batches. Overall, offset printing is the best printing option that is available in the packaging and printing industry for long-run productions. Plus, it offers high-quality color printing and color accuracy that ensures it will meet your quality standards.
So, if you are choosing the offset printing technique for your next project, you can rest assured that it provides you with high-quality packaging at affordable rates that will meet your expectations.
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