Sholes and Glidden typewriter length. The redesigned platen also introduced the modern spacing functionality (horizontal and axial movement providing letter and line spacing, respectively). The cylindrical platen became "an indispensable part of every standard [typewriter]". By the end of 1872, the appearance and function of the typewriter had assumed the form that would become standard in the industry and remain largely unchanged for the next century. Although the machine possessed a cylindrical platen and what was essentially a QWERTY keyboard, two design elements that would later become essential were lacking: the ability to write in upper and lowercase letters and "visible" print. Although the
Particle Transfer Roller passes in contact with it. The rollers themselves are then cleaned, usually in soapy water, and dried before the next use. Particle Transfer Roller The Particle Transfer Roller, often abbreviated to PTR, is a device for cleaning motion picture film. It consists of a cylindrical roller coated with urethane, over which the surface of the film passes. The Particle Transfer Roller was developed by Eastman Kodak and launched in 1989. It was intended to replace the organic solvents that were the main method of film cleaning before that point. Although their effectiveness is not usually considered sufficient for lab operations,