What is the main difference between blue CAD paper and other types of paper?

The main difference between blue CAD paper and other types of paper lies in its specific purpose, historical use, and chemical properties:

Purpose and Use
Blue CAD Paper: Historically used for blueprinting in architectural and engineering fields, blue CAD paper is designed to provide a high-contrast background for technical drawings. It traditionally features a blue background with white or light-colored lines and text, making it easier to read detailed diagrams and blueprints.

Other Types of Paper: Different types of paper serve various purposes, such as office paper for printing documents, photographic paper for images, or coated paper for high-quality color prints. Each type is tailored to its specific application with different properties and finishes.

Chemical Properties and Production
Blue CAD Paper: Traditionally produced using the cyanotype process, which involves coating the paper with a light-sensitive chemical mixture. When exposed to light through a drawing, the paper develops a blue color where light does not reach, creating a high-contrast blueprint. This process results in a distinctive blue background with white lines.

Other Types of Paper: Most modern papers, including those used for printing and office work, are produced using different chemical processes and coatings. These papers often use standard white or colored coatings, with varying finishes like glossy, matte, or satin, and do not necessarily involve the cyanotype process.

Visual and Functional Characteristics
Blue CAD Paper: The blue color provides a specific visual characteristic that enhances the visibility of technical drawings. The color helps reduce glare and makes the white lines or text stand out sharply against the blue background.

Other Types of Paper: The visual characteristics of other papers vary widely depending on their intended use. For instance, photo paper is designed to enhance color accuracy and image sharpness, while office paper is optimized for general printing needs.

Historical and Traditional Significance
Blue CAD Paper: The blue color and the cyanotype process are historically significant in the context of traditional blueprinting. Despite advances in digital technology, the blue paper is still used for its traditional value and specific functional advantages.

Other Types of Paper: Most other papers do not have the same historical significance related to a specific process or application. They are generally developed to meet modern standards and requirements for various uses.

In summary, blue CAD paper is distinct from other types of paper due to its traditional use in blueprinting, its specific chemical treatment that produces a blue background, and its historical significance. Other types of paper vary in their purposes, production processes, and visual properties.