What kind of printing ink do I use?

I use oil based inks for my woodcut prints. Mostly I mix my own colours, using a "transparent base" ink and dry pigments. This avoids the need for many jars/tubes of ink and gives me control over the pigments used. I also just prefer working with transparent colours these days.

Why do I use oil based printing ink?

Partly, I use oil based inks because that was what I was taught to use. But the more important reason is that I prefer the printing quality of these inks. They give me a more consistent and evenly-textured print than water based printing ink.

There are four good reasons to avoid oil based inks:

1. Expense. They tend to cost more than water based inks and are harder to find. For me, as a professional artist selling my work, this expense is justified.

2. Drying time. Oil based inks, like oil paint, can take a long time to dry. I live in a humid climate, and usually leave my prints hanging to dry for two weeks. If they have multiple layers of colours, they take longer. I have the space for a print drying rack, so this isn't a concern for me.

3. Toxicity. The main concern is with the solvents normally used to clean up oil based inks. Soap and water won't cut it. Solvents are toxic to breathe and require proper ventilation. The good news is that you don't need to use solvents. I now clean with vegetable oil instead of solvent. It's a little slower, but not a lot.

Is the ink itself toxic? This is a complicated question. Inks and paints of all sorts are toxic if you eat them, since they contain pigments. Eating ink is easier done than you might think—for example, if you don't clean your hands thoroughly before eating a sandwich—but with a little caution is easy to avoid. Artist quality oil based inks typically have no toxicity beyond this, but commercial printing inks may contain VOCs and require ventilation. You have to check the MSDS sheet to find out.

Long story short, toxicity doesn't have to be a problem with oil based inks.

4. Cleanup. Many artists are intimidated by the cleanup process involved with oil based inks. You can't just wash up in the sink with soap and water. And while the cleanup process doesn't have to be toxic, it does require multiple products (not just vegetable oil), and a lot of time. One complication is that you us a lot of rags, and oily rags can't just be thrown in the trash, they must be contained in an airtight bin, to prevent spontaneous combustion.

For all of these reasons, oil based inks are not typically the ink of choice for beginner or amateur printmakers. And indeed, I don't recommend them to those groups! But since issues 1 and 2 don't apply to me, and I'm able to manage issue 3, that only leaves issue 4 as a consideration. In recent years I've experimented with the alternatives in hopes of cutting down my cleaning time, but ultimately chose to stick with oil based inks, at least for now. You can read more below about why.

What are the other ink options for relief printmaking?

There are four ink options that I'm aware of:

1. Water based ink

2. Oil based ink

3. Water miscible oil based ink

4. Watercolour ink

I've summarized my knowledge and experience of each type below. I should note that my experience with options 1, 3, and 4 is fairly limited.

1. Water based ink

This is the most popular ink choice, especially for beginner or amateur printmakers, but it is also used by many professional artists. This ink comes in a tube and can be bought at almost any art supply store. It looks similar to acrylic paint but is intended to be rolled out with a rubber roller (brayer) instead of spread with a brush. You can clean this ink with soap and water. The disadvantage of water based ink is that it doesn't stay "open" for very long. This means that you have a shorter working time before the ink starts to dry on the roller, palette, and block. In my experience, water based inks have a chalky texture on the paper after they dry, and tend to print with a patchy or uneven effect, but I wonder if these issues may be avoided by using a higher quality ink instead of the cheap Speedball brand I have.

Most people clean water based ink in the sink with soap and water. However, you may have concerns with washing plastics and heavy metals down the drain. Cleaning with soap and rags and putting all the waste in the trash instead of the sink is an option, but at this point, you've really lost the main advantage of working with water based inks.

2. Oil based ink

This is the kind of ink that I use. It stays open far longer than water based inks, which means that it doesn't dry out while you're working, even if you take a break in the middle of printing. You can also save leftover ink and reuse it months later. The printing quality tends to be more even and reliable than water based inks, with richer colours and none of that chalky texture. I have heard that oil based inks may also perform better when stacking many layers of colours, but I don't have direct experience with this problem. I've already outlined a variety of downsides to oil based inks, but if you're printing frequently or professionally, I think these are easy things to work around.

3. Water miscable oil based ink

These are a fairly new kind of ink. If you're familiar with water miscable (also called water soluble or water mixable) oil paints, the idea here is the same. These inks are made with oils, but they have been processed in some way so they can be cleaned up with soap and water. I have tested two brands of water miscable oils. One was Cranfield Caligo Safe Wash. It worked beautifully, behaving the same as the oil based inks I normally used (although I must admit it was a brief test). The other was Speedball Professional Relief Ink, and it behaved pretty much the same as the Speedball water based inks, that is to say, terribly.

As with water based inks, most people clean water miscable inks in the sink with soap and water. However, I've read that this is not a safe practice, and not advised by the manufacturers. This means cleanup would need to follow much the same process as regular oil based inks, just substituting soap for vegetable oil, so I lost interest in further exploring this option.

4. Watercolour ink

Technically this is water based ink, but it is very different from the acrylic variety I describe above. This is the ink used in Mokuhanga, the traditional Japanese method of woodcut printmaking. In Mokuhanga, watercolour or gouache paints are mixed with water in a small dish, then dabbed onto the block. Rice paste is also mixed and dabbed onto the block. Then the colour and paste are rubbed together into the block with a brush (it looks more like a shoe polishing brush than a paintbrush).

Printing with watercolours can create a gorgeously delicate printing effect, similar to watercolour paintings. However, the cleanup process is still time consuming, mostly thanks to those brushes. Mokuhanga is also technically difficult, requiring a lot of control and attentiveness. If you're interested in learning this techniques, I recommend Laura Boswell's book Making Japanese Woodblock Prints.