Mention the word “ink” to someone and they may envision Shakespeare posed pensively with a quill in his hand. They may also picture a man in the days of old milking dozens of squid for their opal liquid. On a less gruesome note, they may also refer to the scribes of feudal Japan who grind bars of charcoal mixed with oils and water to pen the stories, legends and histories of that long ago era. The industrial revolution and mechanization of this process has done away with the romance and ritual of this particular task, but what may surprise a lot of people is that while new technologies have been applied, the general process remains the same.
These days, industry ink is produced much like a food from a kitchen. Various recipes exist to produce inks of various colors and consistencies for different applications. Today’s coding ink is primarily produced in one of two ways; using dry pigment or flushed color pigments. It is not a joke when at the beginning it was mentioned that the general process that ink was produced has virtually remained the same, just take a look at news ink.
Pick up a newspaper and the words you read are made possible by the carbon black dry pigment that has been processed and bound to the paper. Just like the scholar from the feudal days of Japan, the dry pigment used in todays news ink needs to be mixed into an aqueous solution comprised of either some type of oil (such as petroleum or soy bean) or water. Resin is then added to ensure that the ink binds to the paper properly for a solid finish. As you can see not much has changed from the days that Japanese scholars ground sticks of charcoal and mixed them with fats and water to write their calligraphy.
As the use of inks throughout the modern era (think post industrial revolution) has increased with the rise of more and more publications, there was a need to increase the efficiency that ink was manufactured and used. The carbon black dry pigment, for the sake of convenience as much as efficiency, was dry-packed. This made it easy to sell, transport and store, but special care was needed for it to be deemed useable as the pigment tended to clump or form what is known as aggregates. It needed to be dispersed properly into the oil to achieve the proper viscosity needed for it to be run through the printing device and, in the end, on the paper.
Using a device known as a high speed disperser, manufacturers attach a mixing blade to the disperser which works to effectively chop the aggregate dry pigment into smaller sizes and evenly disperse them through the liquid, as well as mix the liquid to the desire viscosity.
Colored inks, on the other hand, do not use dry pigments but instead rely flushed pigments, which is a water-based slurry-like fluid. Since it is already in a liquid state, it doesn’t require the use of high powered milling equipment like a high speed disperser. It does, however, need to be “finished” by mixing it in with oil, varnish and extender to give it the desired, depth, luster and boldness.
Reference: Many thanks to Erryn Deane for providing useful information for this post. Erryn is the digital business manager for The Needham Group of companies.