Soy based ink printing and what it changes on press

Soy based ink, also called soybean ink, is ordinary printing ink with the petroleum oil swapped out for soybean oil. The pigment, resins and waxes stay the same, and only the carrier changes. That single substitution lowers the volatile organic compounds released as the ink sets, makes the ink easier to lift off fiber when the paper is recycled, and, on most work, gives a slightly cleaner color. The printing process itself does not change.

We have printed with soy inks since the beginning. Greg Barber founded Eco Friendly Printer in 1990, and soy ink on recycled stock has been our standard ever since, so customers do not need to request it.

Where soy ink came from

The Newspaper Association of America began looking at vegetable oil carriers in the late 1970s, when petroleum prices made the conventional formula expensive. The first commercial press run using soy ink was at The Gazette in Cedar Rapids, Iowa, in 1987. Newspapers adopted it quickly because it worked on high speed presses and on inexpensive uncoated stock, which is a difficult combination. Commercial printing followed.

What actually changes

VOCs

Petroleum based inks set partly by evaporating solvents, and those solvents are volatile organic compounds. They contribute to ground level ozone outdoors and to poor air quality inside a pressroom. Soy oil is not volatile in the same way, so a soy formula releases far less. This is the clearest benefit, and the pressroom staff are the first to notice it.

Color

Soy oil is clearer than petroleum oil, so pigment reads truer through it. On uncoated and recycled sheets, where ink sinks into the fiber rather than sitting on a coating, that clarity shows. Deep blacks and saturated flats hold up well. If eco inks look washed out on a job, the cause is usually the press setup rather than the ink.

Drying and rub resistance

This is the main tradeoff. Soy ink sets more slowly than a petroleum equivalent, which matters on tight turnarounds and on jobs that go straight into finishing. Slow setting also means a fresh sheet can rub if it is stacked or scored too early. The solution is scheduling and, on some jobs, a coating. Modern formulas have narrowed the gap considerably, but there is still a difference.

Recycling

When printed paper is repulped, the ink has to come off the fiber. Soy based ink releases more readily during deinking than petroleum ink does, which means less aggressive chemistry and less damage to the fiber that gets recycled into the next sheet. If you want a printed piece to recycle well, the ink choice matters as much as the paper.

Soy ink and petroleum ink compared

The list below sums up the differences that matter on a typical commercial job.

• Carrier oil. Soy ink uses soybean oil, often blended with other vegetable oils. Conventional ink uses petroleum-based mineral oil.
• VOCs. Soy ink releases fewer volatile organic compounds as it sets. Petroleum ink releases more, because part of it sets by evaporation.
• Deinking. Soy ink separates from the paper fiber more easily when the sheet is recycled. Petroleum ink takes stronger chemistry to remove.
• Color. Soy oil is clearer, so colors can print slightly brighter, especially on uncoated and recycled stock.
• Drying. Soy ink sets more slowly. A job printed with it needs a little more time before cutting, folding or scoring.
• Press setup. Both run on the same offset presses, plates and blankets. Switching to soy ink does not require different equipment.

Not every ink can be a soy ink

Soy oil content varies a lot by ink family, and in some families it cannot be high. News and cold set inks, which soak into uncoated stock, carry the most. Sheet fed inks for coated and uncoated commercial work carry a substantial share. Heat set web inks, which dry under heat at speed, and UV inks, which cure under light rather than drying at all, carry much less because the chemistry that makes them work requires other components.

This matters when you are comparing quotes. "Soy ink" is not a single specification, and a printer using soy sheet fed ink is doing something meaningfully different from a printer whose only soy content is in a UV formula. Ask which press and which ink family will be used.

The other plant based and low VOC options

• Other vegetable oils. Linseed and safflower oils work on the same principle as soy and appear in blended formulas. Blends are common, so "vegetable based" and "soy based" often describe the same can of ink.
• Water based inks. Water carries the pigment instead of oil. These inks are very low in VOCs, give a softer finish, and are common in flexographic packaging and textile work. They cost more and do not suit every substrate.
• UV and LED cured inks. These solidify under light rather than evaporating, so VOC emissions during printing are low. The tradeoff is the energy used to cure them, and LED curing uses considerably less of it than older mercury lamp systems.
• Algae based pigments. Pigment derived from algae is being developed as an alternative to carbon black. It is a promising development, but it is not yet something we can quote for a general commercial run.

None of these makes soy ink obsolete. For sheet fed commercial printing on recycled paper, which is most of what businesses order, soy remains the practical choice.

How to check a printer's soy ink claim

The claim is easy to make and easy to check. Ask a printer three questions:

1. Which ink family will this job run in, and what is its oil base?
2. Is soy the standard here, or an option that costs extra?
3. What paper is being quoted with it?

The last question matters more than people expect. Soy ink printed on virgin coated stock addresses only part of the environmental impact. The ink and the sheet work together, and the environmental case for either one is weaker alone. We print soy inks on 100 percent recycled, FSC certified stock bleached without chlorine, from mills including Sustana EnviroPrint, Monadnock Astrolite PC 100, Neenah Environment and Mohawk Loop.

Seeing it before you commit

Ink behaves differently on different sheets, and a screen cannot show you the difference. Ask about paper samples when you request a quote, then compare the two or three stocks you are deciding between under the light the piece will be seen in. You can read about each stock on our paper samples page.

What we run with soy inks

Our offset work runs on soy inks. Business cards, letterhead and envelopes, brochures, postcards, menus, greeting cards, invitations, labels, stickers, books and packaging all run on the same materials. The full range with minimums is on our products page, and the reasoning behind our material choices is on why eco printing.

Short runs are available. Minimums vary by product and are listed per item. Typical turnaround is one to two weeks from artwork approval, and it is worth allowing the soy ink its setting time rather than compressing the schedule.

Common questions about soy ink printing

What soy ink is made of

Soy ink contains the same pigments, resins and waxes as conventional ink. The difference is the carrier, which is soybean oil, sometimes blended with other vegetable oils. The share of soy oil varies by ink family, so a soy ink is not 100 percent soy.

Whether soy ink costs more

Ink is a small part of the cost of most print jobs, so the choice of soy ink rarely changes a quote by much. Soy ink is our standard ink, so it does not need to be requested as an upgrade.

How soy ink affects paper recycling

Recycling mills have to remove ink from the fiber before the pulp can be made into new paper. Soy ink comes off more readily than petroleum ink, which helps the recycled fiber keep its quality.

Soy ink and toner

Digital presses print with toner or liquid ink rather than soy ink. Toner has its own advantages on very small quantities, where an offset setup is not worthwhile. We compare the two in is soy ink more environmental than non-toxic toner.

Send us the artwork and the quantity and we will quote it. Start your order and we will come back with paper and ink options and a price.