Drafting Wide Blueprint Papers / Activator
Posted by steve a on February 02, 2014
Large Format Printing Blueprint Paper Wide-Format
In developing blueprint paper, there are 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 various Blueprint Paper Wide-Format Choices. Over 3,000 lbs of blueprint paper was used in the planning and construction that took place before we could enjoy the games live and televised across the globe. Best way to look over what is blueprint paper wide format is to look at it like dictionary does:
In 1861 Alphonse Louis Poitevin, a French chemist, found that ferro-gallate in gum is light sensitive. Light turns this to an insoluble permanent blue. A coating of this chemical on a paper or other base may be used to reproduce an image from a translucent document. The ferro-gallate is coated onto a paper from aqueous solution and dried. The coating is yellow. In darkness it is stable for up to three days. It is clamped under glass and a light transmitting document 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 times this under an overcast sky. Where ultra-violet light is transmitted the coating converts to a stable blue or black dye. The image can be seen forming, when a strong image is seen the frame is brought indoors and the unconverted coating, under the original image, is washed away. 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. The image is stable. The contact printing process has the advantage that no large-field optical system is required. A further advantage is that the reproduced document will have the same scale as the original. Another quality is that the dark blue background makes it difficult to add new information to the print (such as recording as-built changes); a Paper Wide-Format cannot easily be altered -- depending on the situation, this can be either a strength or a drawback. Since the paper is soaked in liquid during processing, a minor change of scale can occur,and the paper can also become brittle. Engineering drawings often are marked to remind users not to rely on the scale of reproductions.
Other blueprint processes based on photosensitive ferric compounds have been used. The best known is probably a process using ammonium ferric citrate and potassium ferricyanide. In this procedure a distinctly blue compound is formed and the process is also known as cyanotype. 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 (Turnball's blue identical to Prussian blue) with the divalent iron. Excess ammonium ferric citrate and potassium ferricyanide are then washed away.
This is a simple process for the reproduction of any light transmitting document. Engineers and architects drew their designs on cartridge paper; these were hen traced on to tracing paper using Indian ink for reproduction whenever needed.
Introduction of the blueprint process eliminated the expense of photo lithographic reproduction or of hand-tracing of original drawings. By the latter 1890s in American architectural offices, Paper Wide-Format Blueprint Paper was one-tenth the cost of a hand-traced reproduction. The blueprint process is still used for special artistic and photographic effects, on paper and fabrics
|Reference : Blueprint Paper Wide Format Blue Print Papers|