Offset Printing

Offset printing is a commonly used printing technique where ink is transferred from a plate to a rubber blanket, then onto the printing surface. It’s called “offset” because the ink is not directly transferred onto the paper. Instead, the image is first transferred to an intermediate surface (the rubber blanket) before being applied to the final printing surface, typically paper.Here’s how the offset printing process generally works:Pre-press Preparation: The process begins with preparing the artwork electronically. This involves converting digital files into formats suitable for printing and creating plates for each color using processes like computer-to-plate (CTP) technology.Plate Making: In offset printing, each color requires a separate plate. These plates are typically made of aluminum or polyester. The plates are created using a process where the image areas attract ink and the non-image areas repel ink.Ink and Water Application: In offset printing, the plates are dampened with water, which adheres to the non-image areas. Ink is then applied to the image areas of the plates, adhering only to the areas with the hydrophobic ink-receptive coating.Transfer to Blanket Cylinder: The inked image is transferred from the plates to a rubber blanket cylinder. The rubber blanket cylinder allows for a smooth transfer of the image from the plate to the next stage without direct contact with the printing surface.Transfer to Paper: Finally, the image is transferred from the rubber blanket cylinder onto the paper as it passes through the offset press. Multiple colors can be printed in succession by using separate plates and blankets for each color.Drying and Finishing: After printing, the ink needs to dry before the paper can be handled further. Depending on the type of ink used, drying may occur through air drying or through the application of heat. Once dry, the printed materials may undergo additional finishing processes such as cutting, folding, or binding.Offset printing is widely used for high-volume commercial printing jobs such as newspapers, magazines, brochures, and books because it offers high image quality, consistent results, and cost-effectiveness, especially for large print runs