There are different types of printing inks available for lithographic printing. Inks are made up of various ingredients such as pigments (organic or inorganic) which create the colour, an oil base liquid that is mixed with the pigment and then dries, and a binding agent made of either organic resins or polymers. The two main types of ink used in lithographic printing are described below.
Petroleum based ink
This is currently the most commonly used ink. It is popular with printers because it dries fast, allowing materials to be printed, finished and out the door quickly. The problem with petroleum based ink is that the petrol and alcohol content evaporates in the drying process, releasing up to 30% VOCs (Volatile Organic Compounds – see below) into the atmosphere. Solvents are also required to clean the press after use – and solvents are another source of VOCs. Petroleum based ink is also harder to de-ink when being recycled, which results in toxic waste.
Vegetable based ink
The environmentally friendly alternative is vegetable based ink. The base liquid for this ink is made from a variety of vegetable oils such as corn, walnut, coconut, linseed, canola and soy bean. Vegetable based ink takes longer to dry but, as a result, releases only around 2-4% VOCs into the atmosphere. Vegetable oils are a renewable resource, unlike petroleum. Solvents are not required for cleaning, as the press can be cleaned with a water based cleaner, reducing VOCs further. Vegetable based ink is also much easier to de-ink when recycling and results in much less hazardous waste.
Vegetable based inks are no more expensive than petroleum based inks. With time we predict petrol based ink will be a thing of the past. The sooner the better!
PrintTogether use vegetable based inks for all printed materials.
THINGS TO AVOID:
There are a few extra things you should also consider when creating your designs and deciding what colours to use.
Metallic ink:Ink that contains metallic particles should be avoided. These inks cannot be recycled and end up in landfill, where they can then leak toxic compounds into the water table. Metallic fragments can also be harmful to animals and humans if inhaled or absorbed. There are other ways to create extra special designs with a standout factor, such as environmentally friendly aqueous varnishes and finishes like embossing or die-cutting.
We recommend not using varnishes. If you do want a varnish on all or part of your printed materials, don’t go for a UV (Ultraviolet) coating. This type of finish may look glossy and nice, but they are detrimental to the environment. They cannot be de-inked which means they can’t be recycled and end up in landfill. UV coatings also require a great deal of energy. Also try to avoid solvent based varnishes as these emit VOCs.
The cleanest alternatives are vegetable or soy based sealer or an aqueous (water based) varnish. However, we strongly recommend not using varnish at all as chemicals are required to wash the machine after use. PrintTogether therefore do not use varnish at all.
Laminating thicker items such as business cards and covers, looks nice and makes them more durable but, again, this should be avoided. These items can not be recycled after they have been discarded and so end up as landfill.