When printing, it is often necessary to use paper, cotton, Mylar and other materials that have been carefully made so that the prints are both accurate and thorough. In addition, it is necessary to spread a solution – which is sensitive to light – over the material. The purpose of using this solution is that it turns into a navy blue color if it is exposed to light. And, if it is not exposed to light, it remains the way it is. As a result, if materials like cotton and paper are used in addition to the light sensitive solution for printing, the print out will be a mix of both blue and white colors. This is the concept behind blueprinting – which is often termed as “cyanoprinting”. In general, designs used for architecture need to use blue prints so that drawings of structures like ships and houses are not only clear but also detailed.
Blueprints are mainly made through contact printing. This requires using a transparent material (Material A) such as tracing paper and even cloth. The drawing that needs to printed is then placed on top of a material (Material B) that has been covered up with the light sensitive solution. Light can easily pass through the transparent Material A onto material B. Then the solution over Material B lets only the exposed parts to be blue and the other unexposed parts remain white. When the blueprint forms, it needs to be cleaned to get rid of all the chemicals on it; this will not affect the colors of the blueprint that are almost permanent.
The concept of blueprints would not have been possible if the famous as astronomer of British origin – called Sir John Herschal – had not made the light sensitive solution using either ammonium ferric citrate or potassium ferricyanide. Both the chemicals contain ferric molecules, and, if exposed to light, the ferric molecules turn into ferric ferrocyanide – which is a navy blue pigment and which does not dissolve in water. Sir John Herschal discovered the chemicals somewhere in the 19th century. Now more than 200 years after his death, the chemicals are being used in what are known as blueprint copiers. Although these are called copiers, they are much more capable than most others in their league – at least when it comes to blueprinting. Blueprint allows a person to easily get hundreds of blueprints from a single master print. This is extremely beneficial in fields such as architecture where new blueprints are needed every day – and sometimes every hour. However, no matter how useful blueprints are, it is certainly no easy task to prepare them. As a result, most normal copiers find it difficult to make blueprints and special copiers – called blueprint copiers – are needed. These copiers are used for both overlays and graphics. They mainly require screens which are sensitive to light; however, sometimes they can also be used with sepia prints, film positives and film negatives.
Blueprint copiers also utilize the concept of contact printing in the sense that a vacuum is required between the master print and the copier. The vacuum allows that the master print and the copier are completely in touch with one another, and that there is not even air to break the contact. Complete contact is very necessary to get decent blueprints. For instance, if substances like air get inside, then the master print will move and cause its copies – or blueprints – to be blurry and unclear.
There are numerous kinds of blueprint copiers available in the market. A few of them are positioned using their own stands; these copiers are usually used only for the exposure of the master print, and another developing system is needed for getting out the blueprints. However, more advanced versions of blueprint copiers can also be found in the market. A few of them are so advanced that they even show a preview of what the blueprint would look like.
The blueprint copiers usually make use of fluorescent lamps to expose the materials. Since the concept behind blueprint copiers and copiers in general is the sensitivity of the materials to light, it is not surprising to know that the blueprint copiers use a total of 18 fluorescent lamps. These lamps usually need power of about sixty-five watts. In addition, the copiers need four other lamps – each with a power of forty watts. These lamps are used to operate the light table. Using a blueprint copier can be difficult – especially because of their complex structures. For instance, all blueprint copiers have both mode switch (to change the setting of the printers) and power switch (to turn the printer ON or OFF). In addition, it is up to the user to decide how long the material will be exposed to light and to decide how much heat will be given. For these purposes, the user needs to use the timer located over the printer.
Many people are probably familiar with wide format copiers and large formal copiers. Both these are basically advanced forms of blueprint copiers, and, even though their names are different, they are used to get replicate blueprints.