In this quick guide to inks we'll cover the toxic and environmental impacts of inks and the various alternatives available. At the end there's a quick summary of inks that don't deink - important information that may change your choice of printing!
Three main environmental issues with petroleum-based ink are:
- Volatile organic compounds
- Heavy metals
- Non-renewable oils
Petroleum-based inks are based on a non-renewable resource. We can't grow more petroleum or crude oil. Check the sustainable graphic design blog from more information on the impacts of oil use and the phenomenon of peak oil. All good reasons to reduce our reliance on petroleum-based products.
Both soy and vegetable inks are made from renewable plant material and can help reduce VOC emissions. Soybean oil-based inks range from 2-5 percent VOC. One major problem with soy ink is that it takes more time to dry than petroleum-based inks, due to its lack of evaporative solvents in the form of VOCs.
The term "soy-ink" does not necessarily mean that the ink is 100% soybean oil. In fact, inks may contain only minimal amounts of soybean oil and still be marketed as a "soy-ink". Printing ink manufacturers in the US can use a SoySeal® logo with various percentages of soil depending on the type of ink. See here for the percentages of soy in the ink.
Here's a link to the SoySeal logo.
Soy inks are more biodegradable than petroleum inks. As the percentage of soybean oil increases in an ink formulation, biodegradability increases. The total amount of ink makes up less than 1% of the paper waste however the deinking process produces a sludge waste of about 20% of the paper mixture when paper fibre is recycled.
Currently black soy inks are priced higher than petroleum inks. However in coloured inks, pigments are by far the most expensive component. Coloured soy inks are competitively priced with petroleum-based coloured inks.
Read more about biochemicals and in particular soy inks by downloading this pdf from pneac.org.
Here's a simple infographic from christineparkdesign.com representing the benefits of using soy-based inks - follow the link for the large version on her website.
These can lessen the environmental impact of printing. Inks are not recycled in the same way as paper, plastics or glass and can't be recycled once they have been printed. Some ink providers can reuse old or spent inks by blending them together to form other, usually darker colours or black ink.
Deinking is the key process in paper recycling. Hydrophobic (water-repellent) ink particles are separated from hydrophilic (water-wettable) fibres. This process has been developed for offset and gravure inks which are roughly more than 95% of the current recovered paper mixture.
Current water based inks create problems as they cannot be removed in this process and accumulate in the system. Dyes and ink particles too small to be removed have no other exit than in the paper fibres. They stain them just as red socks make your white clothes go pink in the washing machine.
Check out the list below of inks that cause problems during the recycling of paper and don't de-ink!
- Digital Prints
- Injet inks
- Flexo inks
- Indigo liquid toner
They also have the Deinkability scores here.
If you want to read more about the principles of ink check out paperrep.com.
For more Quick Guides for sustainable graphic design go to the quick guides page, or use the links in the top right hand column.