This post is about carrageenan marbling size; if you want to know more about marbling in general, check out my post What is Marbling?
What is size?
To create a marbled print (on whatever surface) paints are floated on a thickened water-based liquid called marbling ‘size’, and then manipulated into various patterns using a stylus, comb or rake.
Traditionally either carrageenan or gum tragacanth were used as marbling size – carrageenan, a type of seaweed also known as Irish moss or Irish sea moss, has been used in Western Europe for centuries, and gum tragacanth was very popular in Turkey, although many Turkish marblers now use carrageenan.
Other alternative marbling sizes are methocel and CMC and various proprietary mixtures that I haven’t tried. I will discuss them all (except gum tragacanth and proprietary mixtures, which I have yet to try myself) in this blog. If I try others later on, I’ll update the blog accordingly.
I was going to cover ‘size’ in one post and then realised how long it would be, so this post will just be carrageenan. All have their pros and cons, and for each type I will discuss these.
Carrageenan would have been supplied to marbling workshops as fresh or dried seaweed in the past, from which the active ingredients had to be extracted – a smelly and unpleasant process involving a lot of boiling! Fortunately now it’s available in powdered form, which is much more convenient.
There are three types of carrageenan – you must use lambda carrageenan for marbling size. All three are thickeners for food but the only one that works in marbling is lambda. Don’t be tempted to try the others … trust me … I know. 🙂 In the UK you can buy lambda carrageenan at Marmor Paperie and London Centre for Book Arts.
You’ll find all sorts of recipes for mixing carrageenan, on line, in books, on the packets of size you buy … but fundamentally it’s mix with water. (If you are in a hard-water area you have a problem!*) My recipe is as follows – this is enough for a ‘large plastic marbling tray’ which is what I have to keep reminding myself to call the large cat litter tray I use to produce samples in; the latter name sounds a bit off-putting! You can scale the quantities up or down for bigger or smaller trays.
Carrageenan is a food additive used for thickening, so it’s fine to use your kitchen utensils with it.
My carrageenan recipe
You will need:
- a bucket
- a blender or whisk (I use a hand-held electric blender for soup).
- 3 litres cold distilled water (It doesn’t have to be especially cold, just doesn’t need to be heated)
- 21-27g carrageenan (yes, that’s a big difference, it’s explained below)
Put 2/3 of your water in the bucket and have the blender ready. Add small quantities of carrageenan at a time. As soon as the powder hits the surface of the water it starts to form jelly-like lumps. Blend them in. If you add too much at a time it’s harder to blend, so I just trickle in the powder and keep the blender going. It can be quite splashy – even more so if using a whisk – so do use a bucket and don’t attempt to mix it in your marbling tray. (Ask me how I know!)
Once all the carrageenan is blended with the water add the remaining water and thoroughly blend that in.
You should get a lump free, rather aerated, clear to slightly brown gel/sludge. That’s your marbling size. Pour it in to your marbling tray.
It looks like this:
Have patience! You now need to leave it for an absolute minimum of four hours (more if you used a whisk because you’re waiting for all the air bubbles to rise out of it and if you used a whisk you put more in.) It’s probably best to leave it overnight, but that’s not essential.
When the size is ready it should be completely lump free, clear (no longer looking brownish) and free (or mostly free) from air bubbles.
Using your size
Well I’m going to have to do a whole new post on paints, but traditionally one would use water-colour paint for Western paper marbling, Ebru paints (which are natural pigments, ground down and slowly mixed with water) for Ebru and acrylics or some fabric paints on fabric. I won’t go into full details here.
The first thing you must do is skim the size to remove airbubbles and impurities. You must do this between every print. It will also remove any paint your print didn’t pick up. Take a strip of newsprint (or old newspaper is fine) the width of your tray and 3-4 inches deep. Run this strip along the top of the size from one side of the tray to the other. IT will drag any impurities floating on the surface or air bubbles with it to the edge of the tray, where you can slide the up and remove them. You may need to make several passes.
If the tray is particularly dirty, you can lay a piece of newspaper across the entire tray as though pulling a print and then pull it off. The old paint etc. should come with it. If you do this, don’t leave the newsprint on the size for long – it will start to disintegrate.
To test your paint on the size, put a little paint in the tip of a brush or into a fine pipette, and carefully drop it onto the surface of the size. It should spread over the surface of the size and not sink. Some paints (especially acrylics and Ebru paints) will need additives to help them float and this varies from colour to colour and brand to brand. Let’s assume you’re using Golden Fluid Acrylic paints, as I do mostly. Some colours will spread more than others, and the amount of spread also depends on the amount of carrageenan. The higher the ratio of carrageenan to water, the thicker your size. The thicker your size (up to a point) the more the paints will float but they less they will spread.) You want to achieve a balance, but this balance varies depending on whether you’re doing Ebru (which I do with acrylic paints) or combing – and that is why the amount of carrageenan listed in the recipe varies. For Ebru I’d probably err towards 8-9g carrageenan per litre, for combing I’d probably use 7g – but you can use 8-9 for both. I’ll talk in more detail about controlling spread of paints in another post.
If you want to be more scientific about this than I tend to be, you can try all the paints separately on your size, then try them one on top of the other (drop one drop on, let it spread, drop another colour in the centre.) If you drop a spready paint onto a non-spready one, you may find it sinks, or it might spread out very fast and break up the ring of the less spready paint. Ideally, it will spread out leaving a ring of the other colour around it. If paints are too spready you can’t really thicken them (that i know of) but you can use them strategically e.g. but for comb marbling if you have a particularly spready paint it’s usually best to add this to the tray first, then go with less and less spready paints.
Advantages of carrageenan
This, in my experience, gives the best control of paints. By control I mean when you run a rake or comb through the size, or use an awl for Ebru, the size won’t flow too much and won’t cause too much distortion in areas where the tool isn’t touching the size.
This is enough of an advantage to make it my go-to size, in spite of the disadvantages listed below – and they are legion!
Disadvantages of carrageenan
- The cost – it’s far and away the most expensive marbling size, with the exception of gum tragacanth, which is so expensive I’ve not even tried it!
- The smell – it has a very mild whiff when fresh but after a few days it stinks to high heaven
- The longevity – which could be described as short-gevity! Even if you pour your size into a jug when you’ve finished with it and keep it in the fridge, the absolute maximum time it’s likely to last is a week. Normally I’d give it 4-5 days. In warmer climates even less.
- The changeability – marblers like to tell ourselves that this is one of the charms of marbling. I think in such cases it’s safe to read ‘charms’ as ‘frustrations – we’re trying to kid ourselves’. You can carefully measure out the size with an accurate weighing machine, use distilled water, mix it beautifully … and a change in the weather will mean it just doesn’t work like it usually does. It’s maddening!