A Brief Note on Blue Print and It’s Process

Abstract

Description

A blueprint is a reproduction of a technical design or engineering drawing made on light-sensitive paper using the contact print method. It has been frequently used for more than a century to replicate specification drawings used in industry and construction. A negative of the original, the blueprint process was represented by white lines on a blue backdrop. Colors and grayscales could not be accurately reproduced by the method. The method is now out of date. Major-format xerographic photocopiers later replaced it in large part after being mainly replaced by the diazo whiteprint process.

A photosensitive ferric compound serves as the foundation of the blueprint method. The most well-known method makes use of potassium ferricyanide and ammonium ferric citrate. After being dried, the paper is impregnated with an ammonium ferric citrate solution. A photoreaction occurs when the paper is lit, converting the trivalent ferric iron to divalent ferrous iron. The image is then developed using a potassium ferricyanide solution, which reacts with the divalent iron to produce insoluble ferroferricyanide. The excess potassium ferricyanide and ammonium ferric citrate are then rinsed away. The method is also referred to as cyanotype. Any light-transmitting document can be reproduced using this straight forward procedure. Engineers and architects wrote their plans on cartridge paper, which they then used India ink to trace onto tracing paper for future replication. The sketch on tracing paper is layered on top of the sensitised paper, and both are clamped in a daylight exposure frame a device resembling a picture frame under glass.

The frame is exposed in the daylight for one to two minutes under a brilliant sun or eight to ten minutes under a cloudy sky. When tracing paper is exposed to ultraviolet light, the light-sensitive coating transforms into a stable blue or black dye. The coating does not convert and remains soluble when the India ink inhibits ultraviolet light. One can see the image forming. The procedure is stopped by bringing the frame within when a strong image is seen.

After removing the unconverted coating with water, the paper is then dried. As a result, the original image is duplicated as a white line with the clear backdrop area colored dark blue. The introduction of the blueprint technique did away with the cost of hand-tracing or photolithographic reproduction of the original drawings. In American architectural firms by the late 1890s, a blueprint cost one-tenth as much as a hand-traced replica. On paper and fabrics, the blueprint technique is still utilised to create unique artistic and photographic effects. The underlying materials for blueprints have varied. Paper was frequently utilised; linen was occasionally used for longer-lasting prints, but over time, the linen prints would slightly contract.

Whiteprints

When less expensive printing techniques and digital displays were available, conventional blueprints were rendered useless. This method results in white backdrop with blue lines. Blue-lines or bluelines are other names for the drawings. Similar dye-based designs were also referred to as blacklines. Until they were overtaken by xerographic print technologies, diazo prints were still in use.

Digital

The majority of computer-aided design for machined parts does not use any paper at all; instead, the final design is displayed as an image on the computer screen. A computer numerical control sequence is produced by the computer-aided design programme using the authorised design. The operation of the machine tools used to create the part will be governed by the sequence, which is a computer file. The supervising workers may view the "blueprints" for construction projects like building construction or road construction directly on displays rather than using printed paper sheets. Mobile devices, such as smartphones or tablets, are displayed on these screens. Users can view and annotate electronic drawing files using software. Software is used by construction teams on the job site to update, share, and examine blueprint papers in real time.