Blueprint Key
Gabriel Litke
A blueprint is a reproduction of a technical drawing or engineering drawing using a contact print process on light-sensitive sheets introduced by Sir John Herschel in 1842.[1] The process allowed rapid and accurate production of an unlimited number of copies. It was widely used for over a century for the reproduction of specification drawings used in construction and industry. Blueprints were characterized by white lines on a blue background, a negative of the original. Color or shades of grey could not be reproduced.
The process is obsolete, largely displaced by the diazo-based whiteprint process, and later by large-format xerographic photocopiers. It has almost entirely been superseded by digital computer-aided construction drawings.
The term blueprint continues to be used informally to refer to any floor plan[2] (and by analogy, any type of plan).[3][4] Practising engineers, architects, and drafters often call them "drawings", "prints", or "plans".[5]
The blueprint process is based on a photosensitive ferric compound. The best known is a process using ammonium ferric citrate and potassium ferricyanide.[6][7] The paper is impregnated with a solution of ammonium ferric citrate and dried. When the paper is illuminated, a photoreaction turns the trivalent ferric iron into divalent ferrous iron. The image is then developed using a solution of potassium ferricyanide forming insoluble ferroferricyanide (Prussian blue or Turnbull's blue) with the divalent iron. Excess ammonium ferric citrate and potassium ferricyanide are then washed away.[8] The process is also known as cyanotype.
This is a simple process for the reproduction of any light transmitting document. Engineers and architects drew their designs on cartridge paper; these were then traced on to tracing paper using India ink for reproduction whenever needed. The tracing paper drawing is placed on top of the sensitized paper, and both are clamped under glass, in a daylight exposure frame, which is similar to a picture frame. The frame is put out into daylight, requiring a minute or two under a bright sun, or about ten minutes under an overcast sky to complete the exposure. Where ultra-violet light is transmitted through the tracing paper, the light-sensitive coating converts to a stable blue or black dye. Where the India ink blocks the ultra-violet light the coating does not convert and remains soluble. The image can be seen forming. When a strong image is seen the frame is brought indoors to stop the process. The unconverted coating is washed away, and the paper is then dried. The result is a copy of the original image with the clear background area rendered dark blue and the image reproduced as a white line.
Introduction of the blueprint process eliminated the expense of photolithographic reproduction or of hand-tracing of original drawings. By the later 1890s in American architectural offices, a blueprint was one-tenth the cost of a hand-traced reproduction.[10] The blueprint process is still used for special artistic and photographic effects, on paper and fabrics.[11][self-published source?]
Various base materials have been used for blueprints. Paper was a common choice; for more durable prints linen was sometimes used, but with time, the linen prints would shrink slightly. To combat this problem, printing on imitation vellum and, later, polyester film (Mylar) was implemented.
In the early 1940s, cyanotype blueprint began to be supplanted by diazo prints, also known as whiteprints. This technique produces blue lines on a white background. The drawings are also called blue-lines or bluelines.[12][13] Other comparable dye-based prints were known as blacklines. Diazo prints remained in use until they were replaced by xerographic print processes.
Xerography is standard copy machine technology using toner on copy paper. When large size xerography machines became available, c. 1975, they replaced the older printing methods. As computer-aided design techniques came into use, the designs were printed directly using a computer printer or plotter.
In most computer-aided design of parts to be machined, paper is avoided altogether, and the finished design is an image on the computer display. The computer-aided design program generates a computer numerical control sequence from the approved design. The sequence is a computer file which will control the operation of the machine tools used to make the part.
In the case of construction plans, such as road work or erecting a building, the supervising workers may view the "blueprints" directly on displays, rather than using printed paper sheets. These displays include mobile devices, such as smartphones or tablets.[14] Software allows users to view and annotate electronic drawing files. Construction crews use software in the field to edit, share, and view blueprint documents in real-time.[15]
Many of the original paper blueprints are archived since they are still in use. In many situations their conversion to digital form is prohibitively expensive. Most buildings and roads constructed before c. 1990 will only have paper blueprints, not digital. These originals have significant importance to the repair and alteration of constructions still in use, e.g. bridges, buildings, sewer systems, roads, railroads, etc., and sometimes in legal matters concerning the determination of, for example, property boundaries, or who owns (and/or is responsible for) a boundary wall.
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These are the foundational pillars of the New Era of Smarter Food Safety, covering the range of technologies, analytics, business models, modernization and values that are its building blocks. These elements, working together, will help create a safer and more digital, traceable food system.
The world around us is changing rapidly, and we are in the midst of a food revolution. Many believe we will see more changes in the food system over the next 10 years than we have over the past several decades. Foods are being reformulated, new foods and new food production methods are being realized, and the food system is becoming increasingly digitized. At the U.S. Food and Drug Administration (FDA), we believe modern times require modern approaches.
This blueprint outlines the approach FDA will take over the next decade to usher in the New Era of Smarter Food Safety. It will evolve as food technologies and the food system evolve. It builds on work that FDA has done to implement the FDA Food Safety Modernization Act (FSMA), which established science and risk-based protections.
This document represents the thinking of FDA food safety experts, consumers, the food industry, technology firms, federal and state regulatory partners, our regulatory counterparts in other nations, and academia. Together, we envision a framework that will enable food to be traced to its source in seconds and will utilize new data analytical techniques to strengthen prevention of foodborne illnesses, alerting consumers in real time before contaminated or misbranded foods are consumed. We envision a framework in which education, communication, and democratization of data will enable industry, public health advocates, and government to work in concert to keep the food supply safe.
Smarter Food Safety to me means always looking to the future. Our destination -- safe food for our families, our children, and our animals -- is unchanged. But how do we get there more quickly and effectively using modern tools as the world transforms around us?
When we look at how industries track, through digital means, the real-time movement of planes, ride sharing, and packaged goods or how firms are harnessing big data to identify trends, it is clear FDA and our stakeholders should be looking at how to tap into new technologies that include, but are not limited to, artificial intelligence, the Internet of Things, sensor technologies, and blockchain.
The tools and authorities granted by FSMA create a flexible framework that is adaptable to the changing food safety environment. We continue to make progress in implementing the seven foundational rules that are the FSMA building blocks, which created standards for the production, transportation and importation of human and animal food. Major compliance dates have arrived, inspections are being conducted, and challenges are being addressed.
Fully implementing the remaining FSMA-mandated requirements will help to further prevent contamination. Yet, our prevention framework must continue to evolve. Advances in detection technologies (e.g., whole genome sequencing and enhanced analytics) mean that more outbreaks are being detected than would have been possible to detect in the past. Recognizing this reality, FDA aims to focus on further modernizing prevention, quickly identifying contaminated food, and helping to ensure that it is removed from the marketplace.
Collectively, FDA and all stakeholders should strive to ensure that we are doing everything possible to quickly incorporate the lessons learned from contamination events into prevention efforts, and to complete our work as expeditiously as possible.
Our world is evolving at a breakneck pace. With this evolution comes new technologies, ranging from new digital tools to new sources of food ingredients. It also comes with new business models, like e-commerce and omni-channel food distribution, which covers a range of online, mobile device, telephone, and brick-and-mortar store shopping platforms. These advances provide new tools and approaches for tackling food safety issues, but also present new issues to consider in determining how to regulate food safety.
We plan to engage a broad expanse of stakeholders in industry, academia, trade associations, and consumer groups, as well as our state, federal, international and other regulatory partners, and groups that we had not traditionally engaged with before, such as technology companies.
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