Essentially, Emily talks about modifying inks as a last resort. If you're having problems with your printing the issue is likely with your plate. I tend to agree with her. Your inks were made by smart people who know what you need them to do. They're designed to do it well. Your plate was made by a student who's just starting to figure this process out.
It is true that different companies make their ink differently. As you gain experience you'll come to know which inks you like better for which tasks. Emily writes briefly about a couple of blacks that Crown Point uses for different purposes, one of them is good for most kinds of prints and the printers at Crown Point like the two mixed together just for printing drypoints.
So, Emily's first word in ink modification would be that you probably don't need to modify your ink. Or at least that you need to modify it very little. If you're having a problem with your printing it's more likely that it's an issue with your plate than the ink.
Having said that, you will have plates with problems which will require you to modify your inks and, very occasionally, you'll want to modify your inks for some other reasons. Instead of simply telling you what to do in a given situation, it's better that you know what ink is made of and why it does what it does.
Ink is actually very simple. You can click this sentence to get to Linda Cote's blog entry on making and printing with her own ink. Here's a video demonstrating and explaining how The Printing Ink Company makes ink for publishers:
As you learned from the blog and video ink has two main parts, the pigment and the vehicle. The pigment is simply a colored substance in the form of a powder. In theory, pigments can be made from anything. If you look at the names of colors you can guess where they come from. Lamp Black was once actually made from lamp soot. Prisoners still make tattoos using lamp soot mixed with urine as a binder. Bone Black was made from burning bones. Often when an artist needed a color they went into the countryside around their town and found colored dirt and rocks that could be ground finely to make pigments. Burnt Sienna is named after some earth near Siena Italy. Artists used to grind it down, cook it in a pan, mix it with a vehicle and paint with it. Clicking this sentence will take you to a page describing various pigments and their origins.
|Aboriginal Ochre Pit - CentralAustralia|
At this point in the history of the world, ink-makers have found more and better ways to make the best, longest lasting pigments. George Washington Carver could make any color you want from Alabama dirt and a few chemicals. That's more or less how it's done now. Most colors are still made of things mined from the earth but chemicals are usually brought into the process to help with consistency.
It is important to note that many pigments and the chemicals used to make them are highly toxic.
One of the first things you will notice about your ink is how thick it is. The density of the pigment in the vehicle is one of the factors that determines thickness. More pigment equals thicker ink. Eventually you could mix in so much pigment that you overwhelm the vehicle and end up with a dry, crumbly little clump that's not good for anything.
The vehicle is the other thing that determines thickness. Vehicles can be a lot of things too. Vehicles that have been used to carry pigment include boiled urine, plastic, rubber, various oils, turpentine, egg yolk, glue and plain old water. In a general sense it doesn't matter what the vehicle is as long as it does two things; it has to hold the pigment in suspension and it has to dry in the air.
Of course, all of these vehicles behave differently. So, it's important to know which one you're working with, what to expect from it and how to modify it to do what you need. Oil based printmaking inks, which we will use for everything but screen printing, are made using Burnt Plate Oil. Burnt plate oil is simply linseed oil that has been set on fire for a period of time. The longer the burn the thicker the oil. Ink makers take this into account when making their products and different manufacturers use different densities to achieve what they believe to be the best ink.
|Thick Oil - Notice the No. 8 on the can.|
The balance that all ink manufacturers are looking for is between pigment saturation and workability. High pigment saturation is desirable as an artist can apply the ink in a thin layer and have good, consistent color coverage. However, if there is too much pigment the ink will become dry and difficult to work with. Too little pigment will mean that the ink is runny and sloppy and won't give good color coverage.
There are a few variables. If the vehicle is already pretty thick it won't be possible to add much pigment before the ink becomes dry, clumpy and useless. If the vehicle is too thin the manufacturer will be adding more pigments than are really needed for consistent coverage. And the pigments are often expensive. So, the preferred ink is made from a medium thick oil that will take enough pigment to ensure consistent coverage without becoming too thick and dry.
The main variable that has caused me frustration is that different pigments interact with the oil differently. Some pigments will absorb the oil others won't. It might take more of some pigments to get consistent color coverage. So, a red might behave slightly differently from a blue made by the same manufacturer. Or an ink might be made differently because of the job that it was intended to do. For example, one of the things that white is intended to cover up other colors completely. That's a hard job. So, white ink is usually loaded with pigment and pretty thick. These things aren't usually problems when the ink is new as manufacturers strive for consistency. But as an ink ages it's behavior changes and differences come out.
This begins to explain the variety between different manufacturers' inks. It also tells you what you should be thinking about and looking for when you modify your inks in the studio. One thing that might not be so obvious is that any modifier you add to an ink is going to increase the amount of ink without adding more pigment. So, you're diluting your color saturation. You can add quite a lot to an ink before this becomes a problem, but be aware of it.
You're only going to modify your ink in three ways.
The first one is to mix two kinds of ink together. You might do that in order to have an ink with characteristics between the two, as in the crown point example. Mixing a color inherently involves mixing inks together. Be aware that when you mix a color you'll also be averaging the properties of the inks used. Sometimes colors from the same line will have slightly different properties.
The second one is to thin your ink by adding more burnt plate oil. This is the same as diluting it. Why would you do that? If the ink you're using is too short.
The third one is to add Magnesium Carbonate as a thickener. Printmakers refer to thicker ink as stiff or short and increasing the thickness as stiffener.