Lithography is a core process in the production of advanced technologies and is widely used across printing, electronics, and integrated circuit manufacturing. Using light to create precise patterns on photosensitive surfaces, it enables the production of images and text.
Since the introduction of lithography in …printing industrythis technique has become one of the key tools in microelectronics engineering and is used to manufacture chips and electronic devices with micrometer-level precision. One important application of print lithography is in the process of …Offset Printingwhere images and text are reproduced with high accuracy on various materials. Using a lithography unit in this workflow ensures precision and quality for complex print jobs. In this article, we answer what lithography is and what it’s used for, and we explore its applications across industries.
Contents
What is lithography?
Lithography is one of the stages of offset printing. In lithography, aluminum plates—often called zinc plates—are produced. Because of its importance, it’s sometimes referred to as the “mother” of the printing industry.
The word “lithography” comes from Greek: “litho” meaning stone and “graph” meaning to write or engrave. It literally meansstone printingand originally referred to a process in which images and text were printed from a stone surface.
As a technical process, lithography creates precise, complex patterns on photosensitive surfaces. It was first used in printing to transfer images and text onto materials such as paper and metals. As you know, all colors are formed from combinations of three primary colors—red, yellow, and blue. In this method, a light-sensitive layer is applied to a surface and exposed with light (or other radiation) to create the desired pattern. In lithography, each aluminum (zinc) plate prints one color so that, by combining three colors, the desired hues are obtained. The zinc plates themselves do not accept ink; instead, the polymer layer imaged on the plate takes up the ink completely. The prepared plates are then sent to the print shop for production on paper.
What is a lithographic plate (zinc)?
In lithography, the design is transferred to a printing plate made of metal—commonly called zinc or plate. Its surface is coated with a photosensitive layer, typically a polymer compound that reacts to ultraviolet light and evaporates upon exposure.
To create the image on the plate, transparent films are first made from the design, containing dark and clear areas. These films are placed on the plate and exposed to UV light. Where light passes through the clear film, the photosensitive coating evaporates. In the darker areas, the polymer remains. The plate is then washed in an alkaline solution—often ammonia-based—to remove residues from exposed areas so the image fully appears. A subsequent bath stabilizes the unexposed regions, preparing the plate for printing.
Traditional method of making plates
In the older approach, print films were produced first and then used to expose the image onto the plate. Plate-making therefore involved two main stages: film production followed by exposure to create the plate.
Modern method: using a Plate Setter
With technological advances, the Plate Setter was introduced, eliminating the film stage. The design file is sent directly from the computer to the device, and the finished plate is imaged in-line. In effect, the plate setter works like a digital printer for plates. This method increases accuracy, reduces time and cost, and allows quick design adjustments.
Note: In print industry parlance, the metal sheet produced via the traditional method is commonly called “zinc,” while the digitally imaged product is called a “plate,” even though they function similarly.
Types of Lithographic Plates
Row | Plate Type | Features & Applications | Plate Base | Light Sensitivity | Best For |
1 | Diazo Plate | Requires exposure; durable image; good quality | Aluminum | Yes | Medium to high runs |
2 | Photopolymer Plate | High detail accuracy; excellent image definition | Aluminum | Yes | High-quality printing |
3 | Silver Halide Plate | Very high light sensitivity; suited to specialized printing | Aluminum | Very high | Commercial print & packaging |
4 | Silver Halide on Film Base | Lightweight; economical; lower durability | Polyester | High | Short runs or test prints |
5 | Silver Halide on Metal Base | High quality; longer life than polyester | Aluminum | High | Medium-run printing |
6 | Bimetal Plate | Two-metal construction; high strength and longevity | Metal combination | Yes | Very high-volume printing |
7 | Electrostatic Plate | Imaging without light; similar to a laser printer | Polymer or metal | No | Fast, no-exposure printing |
8 | Waterless Offset Plate | No dampening needed; high accuracy and stability | Aluminum | Yes | Waterless offset |
9 | Ablative Plate | Image removed physically by laser; no chemical processing | Aluminum or polymer | Device-dependent | CTP and advanced digital printing |
Lithography Equipment
This device outputs all four color separations from the original file in black onto transparent film. In essence, an imagesetter is a large-format, high-precision monochrome laser printer capable of imaging on clear film. Its resolution is very high, making it suitable for accurately reproducing fine details related tocolor in printingAfter the films are prepared, they are mounted to raw zinc plates and fixed with special clamps. The plate surface is coated with an ink-receptive polymer, and during plate-making the excess areas are removed so only the image remains. In effect, imaging on the plate is the reverse of conventional on-paper printing.
What is lithography used for?
To understand what lithography is and what it’s used for, consider its broad impact across industries. Using optical and chemical methods, it enables the creation of precise patterns on many surfaces. Below are the main application areas:
Row | Application Area | Description |
1 | Printing & Publishing | Used in the production of books, newspapers, magazines, and brochures. Employed in devices …Roll printingFor precise and high-quality printing on large-scale paper. |
2 | Production of commercial packaging | Printing on cardboard boxes, cartons, and product labels. Creating clear images with vibrant colors to attract customers. |
3 | Electronics and microchip industries | Used in the production of semiconductors, chips, and processors. Enables the creation of precise patterns on silicon surfaces in micron-scale processes. |
4 | Medical and laboratory equipment industry | Manufacturing sensors, microscopic tools, and diagnostic equipment. Utilizes optical and electron lithography to produce highly precise and tiny components. |
5 | Textile industry and fabric printing | Used for printing precise and colorful designs on various fabrics. Ensures high quality and color durability in clothing and decorative product designs. |
What are the steps of lithography?
1. Design preparation
The first step in lithography is designing and preparing the graphic file. This design includes images, text, and desired colors to be printed on the final material. Designers use graphic software like Adobe Illustrator or CorelDRAW to create print-ready files. After design approval, it is converted into a suitable format for lithography. Depending on the project and printing requirements, various lithography methods, such as offset printing, may be used.Digital Printingused.
2. Transferring the design to a plate
In the second step of lithography, the prepared design is transferred onto special metal plates called plates. This process is typically done using lithography machines and optical printing devices. For color lithography printing, each primary color (cyan, magenta, yellow, and black) requires a separate plate. Precision in this stage is critical, as the final print quality depends on the accuracy and alignment of the plates.
3. Preparing the plate for printing
After the plates are prepared, they are coated with special chemical solutions to create hydrophilic and oleophilic properties in different areas. The designed areas attract ink, while the non-printed areas absorb water and repel ink. This distinction forms the basis of lithography's functionality.
4. Transferring the image to a blanket
In this stage of lithography, the plates are mounted on special cylinders in the printing machine. The ink is transferred from the plate to a rubber layer called a blanket. The blanket acts as an intermediary between the plate and the paper, ensuring the ink is applied evenly to the printing surface. This method enhances precision andUV print qualityaccuracy.
5. Printing on the final material
In the final stage, the blanket transfers the image onto paper, cardboard, or other printing materials. This process can be performed at high speed, making it ideal for large-scale printing. After printing, additional finishing processes such as cutting, thermal lamination, or embossing may be applied to prepare the final product for delivery.
You might find this interesting:Setting up a printing press
Color separation and design transfer in lithography
All printed images are created from a combination of four primary colors: cyan, magenta, yellow, and black, which together produce millions of colors with varying contrasts. The role of lithography is to separate these four primary colors from the submitted designs. After the design is sent from the graphic studio to the lithography department,Nami Naghshit is first reviewed by an operator using various graphic software. If no issues are found, color separation is performed, and the screen type is selected based on the type of paper or cardboard to be printed. Then, using advanced lithography systems, each color's image is transferred to a plate based on the defined screen. The color separation transfer to the plate is done either directly (via platesetter) or indirectly through film (via imagesetter). Note that in some graphic designs, to enhance the visual appeal or create a luxurious effect, a fifth or sixth color may be needed in addition to the four primary colors, such as gold, silver, or Pantone. In both cases, the separation and execution processes are similar. After these steps, the plates are checked by the operator and sent to the printing hall.