People are often confused by the difference between transparent ink and linseed oil, and how these two elements affect your inks for printmaking.

It is a common question and I hope this blog post will help to reduce the confusion.

As with many printmaking issues there is a bit of brain teasing involved….. we will be looking at consistency of ink and also density of colour.

pot of transparent ink

Defining words; what’s in a name?

I mostly use Hawthorn inks and they produce ‘transparent ink’; other manufacturers call this ‘extender’. Extender and transparent ink are the same thing, just with a different name, I will refer to it as transparent ink here because that is the habit I have got into.

What is transparent ink?

Most modern ‘safe’ printmaking inks are based on vegetable oils – soya and linseed for example. The base is mixed up first, and then different pigments are added.  Transparent ink is the base with no colour added. Hawthorn transparent ink is like honey.

transparent ink on a palette knife

Don’t mess about with your stock ink pots

I want to say this right from the start; printmaking inks are expensive so look after your stock pots – don’t add anything extra to them, keep them as clean and stiff as they came from the factory. They will last you a long time.

I use little tins or jars and scoop some ink out of the stock pot with a clean knife to into the smaller container. Then you can begin to customise it by adding oil, transparent ink or other colours, and leave your stock pot untouched. The Hawthorn colours are ‘stay open’ so they will keep in the small pots for many months without getting a skin or drying out.

I always mix inks

I hardly ever use ink straight from the stock pot. I always alter the transparency and consistency. Generally the colours in the stock inks are too dense for collagraphs and the consistency is too stiff.

I have found that many of the problems people have with inking collagraph plates arise from assuming the ink in the stock pot is ready to use.


Consistency of inks

Because transparent ink is the base ink with no colour added it is much the same consistency as coloured ink; perhaps slightly runnier if you compare a new tub of transparent with a new tub of coloured ink.

If you mix transparent ink with coloured ink the consistency will not change.

blue and transparent ink in pots
collagraph with transparent ink

What will happen if you add transparent ink?

The consistency of the ink is the same but the particles of colour are more spaced out through the transparent ink. Colours become more subtle, and depending on the percentage of transparent to colour you can achieve delicate watercolour like effects.

A new colour will appear where two transparent colours overlap (e.g. blue over yellow will give you green)

The textures on a collagraph plate will become more distinct and have greater depth if you use more transparent ink for your intaglio inking. This is because the colour is still dark in the grooves but you can wipe it much lighter on the top surfaces, producing a greater tonal contrast.

How much transparent ink can you add?

If you print with clean transparent ink it is pretty much invisible. I sometimes ink up a used collagraph plate with just transparent ink at the end of a session – this mixes with the residue of coloured ink left on the plate and can produce very interesting prints which look quite different from a ghost print.

If you have, say a tablespoon of transparent ink and add a pea sized blob of colour you will have a delicate shade.

Experiment with different amounts of transparent to colour to see what happens. If you have plates made from crisp packets or melted Tyvek you will probably find a highly transparent ink mix gives much better results.

blue and transparent ink mixed in different proportions

What about opaque inks?

Opaque inks have white mixed in with the colour, they have a chalky appearance. They are dense and will obliterate any colours underneath them. I suggest using opaque inks for relief inking, not intaglio, because their lack of transparency can make collagraph textures look flat and heavy. They can also tend to look muddy when mixed with other colours for intaglio inking. However, if you add a lot of transparent ink to opaque colours you will get a misty effect which can be nice to experiment with.

So where does linseed oil fit in?

Linseed oil changes the consistency of the ink, making it runnier. It does not really affect the transparency.

pot of linseed oil

Why alter the consistency of printmaking inks?

With traditional metal etching plates, the ink used is quite stiff, the metal plate is very strong and can withstand some hard wiping without suffering any damage. A stiff ink with plenty of pigment will stay in the fine etched lines and give a good clear printed image.

If you are working with collagraphs it is a quite different approach; the plates are often fragile, made from card and paper, and generally have a lot more texture on them. The rough treatment you give a metal plate would quickly damage the collagraph plate.

The answer is to make your intaglio ink runnier. This is kinder to the plate, easier on your hands and arms and generally makes your life much easier. See this post for info on inking up collagraph plates.

How do you change the consistency of printmaking ink?

I add linseed oil.

Hawthorn also sell linseed oil reducing jelly, this is like soft butter and will also make the inks runnier. Some people love it, some don’t really get on with it.

Because I like to make my inks quite runny, I find ordinary linseed oil works well.

It is also best for mixing inks for viscosity printing, but I don’t want to complicate things so won’t say any more about that here. (See the blog post)

linseed jelly on a knife
red and transparent ink in a pot
adding linseed oil t the inks

Once the transparent ink and coloured ink are in the small pot, add a slug or two of linseed oil and mix it in well with a knife. It goes through different stages before it is properly mixed, it may seem quite thick and lumpy but when the oil is combined with the ink it should be like runny treacle. Keep adding oil till it feels right. The ink can be ‘painted’ onto your collagraph plate with a hogs-hair brush, it is that runny.

The temperature of the studio affects the inks – in warm weather they will be runnier, and they go stiff in the cold.

painting ink on the slab

How runny is too runny?

If you can easily wipe all the ink off your plate with a rag it is too runny. If you end up with a mix like this you may be able to use it for a mono print or a very delicately wiped collagraph. I’d suggest doing some experiments to discover the consistency you like. Some plates work well with quite runny ink, e.g. if you have a lot of carborundum on the plate, runnier ink can make inking up much easier.


Solvents alter the consistency of inks and make your ink runnier, the purpose here is to make it so runny you can clean it off surfaces, not to print with it. Vegetable oil or baby oil is cheap and will make the ink runny enough to clean up, it is not suitable to use in prints, as it doesn’t dry in the same way as linseed oil does. Using linseed oil as a solvent for cleaning up would be expensive, and if you left a residue on rollers etc it could harden over time.

woman thinking


Were you concentrating?

1. What is transparent ink

2. What difference can transparent ink make to your collagraph prints?

3. How does linseed oil affect transparency?

4. What two things affect the consistency of your inks?

We all get into habits with printmaking and it is good to try out some different approaches. I hope you make time to experiment with transparent inks and also try altering the consistency of your inks – you may find it makes more difference than you imagine.