{"id":6489,"date":"2013-01-15T16:41:15","date_gmt":"2013-01-15T16:41:15","guid":{"rendered":"https:\/\/www.solopress.com\/blog\/?p=6489"},"modified":"2022-06-28T12:47:26","modified_gmt":"2022-06-28T11:47:26","slug":"thermographic-printing","status":"publish","type":"post","link":"https:\/\/www.solopress.com\/blog\/print-inspiration\/thermographic-printing\/","title":{"rendered":"Thermographic printing – the art of thermography"},"content":{"rendered":"
<\/div>


\nThermographic printing is a fantastic printing technique that is commonly used on greeting cards<\/a>, wedding invitations<\/a>, and other printed materials that require embossing with a natural look and feel to them. Some printers use this process to make printed font or image elements 3D-esque, as do many hobbyists who engage in the delights of crafts for their own homemade projects.<\/p>\n

\"thermographic<\/p>\n

Image credit: The Potting Shed<\/a><\/em><\/p>\n

To fully understand the art of thermography we are going to explain the processes that a printing company goes through to produce this great and somewhat forgotten method of print, in addition to a run through of how you can make your own crafty version of it at home.<\/p>\n

The Origins of Thermography<\/h2>\n

Unfortunately the exact origins of thermography are not entirely clear but according to British Letterpress<\/a> it dates back to a time when engraving was the preferred method of styling fonts or designs for high-class stationary and other substrate.<\/p>\n

Engraving is a very traditional method of artistic printmaking and originally involved the engraving of a copper or zinc metal plate, which would produce the reverse of the intended design. The grooves created would then be filled with ink that transferred to the substrate (usually paper) under the application of high pressure, leaving a slightly raised print.<\/p>\n

\"engraved<\/p>\n

Image credit: Alonglongtime<\/em><\/p>\n

Because new plates needed engraving for every project, which involved a great amount of time and skill, this method was, and still is, one of the most costly printing processes. Hence, thermography was born, providing raised print that utilised the moveable type printing presses at much more affordable prices for both the printers and consumers.<\/p>\n

The Method of Thermographic Printing<\/h2>\n

Thermography normally involves three simple processes. To begin with we will explain the method used by professional printmakers, followed closely by a quick tutorial on how you can achieve the same embossed effect at home if you want to try it yourself.
\n\"3
\nThe diagram above is a graphic representation of the three-process method of lithographic printing. The substrate, once printed on, is passed through each process on a conveyor belt until the final product is created.<\/em><\/p>\n

Step 1<\/h3>\n

Note: prior to this phase the transfer of ink to paper needs to have been made by any printing technique that ensures the ink is still wet, such as letterpress. Pigment inks are usually used for thermographic printing because they are slow drying.<\/p>\n

The first process of thermography involves the application of a powder commonly known as embossing\/ thermographic powder<\/a>. Made from plastic resins, the powder coats the page and attaches itself to the wet ink (the areas selected for embossing).<\/p>\n

Step 2<\/h3>\n

The substrate moves from the powder stage on to the vacuum process where the excess powder is removed from the paper, leaving only the inked parts coated and ready for the final stage.<\/p>\n

The removal of excess powder is not always done with a vacuum. Instead there are some machines that use a combination of vibrations and a conveyor belt with runners that alter the orientation of the page (from horizontal to vertical) to allow excess powder to deposit into a sump, which is recycled and applied to following application processes in step 1.<\/p>\n

Step 3<\/h3>\n

Once the powder has been applied and the excess removed, the substrate finally reaches the transforming process where it is passed through a radiant oven, exposed to temperatures between 900 and 1300\u00b0C (Wikipedia<\/a>) for 2 to 3 seconds.<\/p>\n

As it passes through the oven, the substrate rises in temperature, causing the powder-coated elements of the page to melt and transform until they look shiny, raised and slightly bubble-like.<\/p>\n

The printed product then continues along the conveyor belt to cool once taken away from the heat and deposited in a paper collection tray of some kind. Some machines have a fan to cool the substrate as it exits the oven, however, this is not entirely necessary as the melted elements begin to dry and solidify once removed from the heat of the oven.<\/p>\n

Extra Info<\/h3>\n

As we explained in Step 1, the transfer of pigment ink to paper needs have been made first to provide wet ink that the embossing powder can adhere to. Ideally a conveyor would run each printed piece of substrate from the printer to the first process of the thermographic procedure to ensure that the ink remains wet.<\/p>\n

Common Problems<\/h3>\n

Like all printing there is a great deal of balance involved. These are just a few common problems that can occur with this printing process:<\/p>\n

    \n
  • If the ink is too dry then the powder will not adhere to it;<\/li>\n
  • If a sufficient amount of excess powder has not been removed then it can make the finished product appear blotchy;<\/li>\n
  • Too much heat could cause the paper to ignite;<\/li>\n
  • Too little heat could make the design appear too uneven with some elements melted and others not.<\/li>\n<\/ul>\n

    Video Resources<\/h3>\n

    Here is a video that clearly shows how a hand-fed thermographic printing machine works:<\/p>\n