Monday, October 20, 2008

INK: Soy vs. Oil vs. Rubber

Really there shouldn't be a competition between these different ink types, but it seems that we are being asked this question more and more often - and with good reason. Clients want to make sure we are being a friend to the environment and we applaud their concern. So a while back we spent a little time learning more about the oil-based ink we use. While we can use soy inks, to date we have been mixing oil-based inks and also have a few rubber-based inks.

Here's our take on the soy vs. oil-based debate:
  • The inks that work best for us are not “soy-based” although they may contain some soy oil. When we looked into the actual composition of various inks, it turns out that soy inks are not vastly different. If not soy oil, most oil-based inks use linseed oil, which has been used for centuries in oil paint, etc. It also is plant based, and time proven. The breakdown of the ink is something like 20-30% oils (of either kind), 10-20% pigments, around 40% resins, and some other things such as drier or varnish.
  • In the very small quantities we use, there is no significant difference in VOCs emitted, or other environmental standards. Soy ink shows these advantages in large print runs such as newspapers, national mailings, and so forth.
  • The soy ink that is readily available to us is sort of “soupy,” and requires adding modifiers to reach the desired stiffness. Thinner inks make the printing appear sloppy as they “squeeze out” under impression.
  • The drive for soy inks came from a marketing council of soybean growers. When a printer of our size proclaims their use of soy ink, we wonder if it is more of a marketing tool than a concrete environmental difference. If the soy oil replaced volatile solvents like toluene or benzene it would be a clear advantage, but linseed has worked well for ages and has no ill effects that we know of.
  • We mix all of our inks by hand so even though we are a commercial letterpress shop we only have a can or maybe two of just the pantone mixing inks instead of buying a new can of a single PMS each time someone orders a new color. Common print jobs typically use a small amount of ink – about the size of a quarter. This helps us to be better to the environment instead of having a bunch of ink that might not ever get used sitting around.
  • We've also decided to start making the switch to rubber-based inks because of their anti-skimming properties. This keeps more of the ink more usable over time.

5 comments:

Jenni said...

Thanks for shedding light on this hot topic! We are in the same boat - small letterpress shop, not impressed with soy-based inks. My press operator is very concerning with the environmental and health issues related to printing inks and chemicals; he researched soy ink and, like you, concluded that they are not markedly more "green" than other sorts of inks. We love rubber-based inks because they stay open longer on the press (if we used soy-based inks, we would have to clean our press more often, using more solvents), and the cans don't skin over, so we waste less ink in the can.

Daniel said...

In the traditional printing process, water is combined with ink so that colors are clearly differentiated on the paper. Moreover, chemicals like isopropyl alcohol are used for the printing purpose. With waterless printing, you will not only save water but you will be prevented from being exposed to harmful chemicals.
Green Printing

Elaine Biss Designs said...

Thank you for writing about this. Personally, I like soy. I don`t use any solvents and the only chemical I use is non stick spray to clean my press.

DavidD said...

Good post. I appeciate your detailed explanations. I had thought of using soy as well but as you said, Linseed is plant based and works. I am currently using several cans of oil based ink that are easily 30 years old with excellent results. The skins are thick but the usable ink works very nicely. When I do buy new inks, I'll likely buy ink in tubes to resolve the skinning issue. Thanks again.

Johnson said...

Very informative blog. Thanks for sharing such great post.

Soy Ink Printer