1. Offset Press Operations Amy Hicks 2010

2. Essential Question What is Offset Lithography and why is it one of the most common types of printing today?

3. Offset Lithography

4. “Offset” “Lithography” Based on the concept that grease and water do not mix Grease = ink Water = fountain solution Planography - The process of printing from a flat surface with the image and non-image areas kept separated by chemistry.

5. Offset Lithography (continued) “Newest”, but most commonly used form of printing. Used in short to medium runs (500 – 100,000) The image is first transferred from a plate to a blanket, then from the blanket to the substrate.

6. Offset Lithography (continued) Able to print on a variety of substrates Different sizes Different weights of paper BUT…. All substrates must be FLAT! Remember Planography – process of printing on a flat surface. Press is easy to learn and easy to operate – But it does take skill!

7. Offset Lithography (continued) Typically the most economical form of printing (inexpensive) Presses are typically “small” and are affordable

8. Offset Lithography Presses

9. Web vs. Sheet Web Fed Press: Printing press that prints from a roll of paper Sheet Fed Press: Printing Press that prints from cut sheets of paper Web Fed Sheet Fed

10. Perfecting Press Perfecting Press – Prints on both sides of the paper with one pass.

11. Offset Lithography Plates First things first….

12. Offset Lithography Plates Hydrophilic – Water Loving Non-image area of the printing plate Hydrophobic – Water Hating Image area of the printing plate Plate is coated with water 1 st, then ink

13. Offset Lithography Plates Several Different Types of Plates: Metal Plates Polyester Plates Paper Plates Depends on type of press, length of run, and price for which one you will choose

14. Offset Lithography Plates CTP – Computer to Plate Imaging systems that expose fully- paginated digital materials to plates in plate- setters or image-setters without creating film intermediates. In other words – The image goes directly from your computer software to the printing plate as if you were “printing” it like on a laser printer. EASY!