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Using Methycellulose for Oil Painting

by David Clemons

Dec. 6, 2006

 

 


Methylcellulose
: A water and oil emulsifier for use in oil painting

What is it?
Methylcellulose (MC) is a chemically processed starch of cellulose ethers made from plant fiber, usually wood or cotton. The powder gels into a viscous liquid in water to make a weak glue and resilient film almost like thin plastic. There is another variety of it called sodium carboxymethylcellulose (CMC) which has a stronger adhesive property, but the sodium makes it slightly more crystalline, and MC dissolves more easily in water (smoother.) It's less prone to mold than animal glues and other starches, has virtually no shrinkage when it dries, and will not spoil.

How is it used?
As a glue, it is often used in bookbinding and paper repair for conservation purposes. It can be found in soft pastels and chalks as a binder to hold the pigment together, or used for sizing paper, and in making wallpaper paste. It is completely non-toxic, and can also be processed as a food additive and candy glaze. Ceramists use CMC to help harden the glaze on pottery. As a paint ingredient, MC is used as an emulsifier or plasticizer along with other binding agents and liquids. For oil painting, it can replace or extend the use of oil mediums, and can be thinned with only water.

I first read about using MC while doing research on egg and oil emulsions. It was recommended as a substitute for egg, so I started off on a parallel search for more information about it. I was living in Montreal at the time, and I saw a bottle of the powder on the shelf of a local art store, so I took some home to try out.

Preparation:
The bottle I bought (Sennelier "Liant [binder] Methyl Cellulose") had no instructions, so I decided to try a recipe I found for mixing casein glue from powder. I added 10 drops of white wine vinegar (to make the powder dissolve better) to 8 to 10 tablespoons of distilled water, and slowly stirred that into 1 tablespoon of powder. If it gets lumpy at this point, stir vigorously until it smoothes out. This creates about 4 ounces of a clear, viscous liquid that I would use as my medium. I let the solution sit for a few hours to gel properly before using it.

For Painting:
Without any reference to go by as to how to use it, I approached it as I would other oil mediums, nothing more than 25% or so by volume. I added a small amount to oil paint and it mixed easily, and it brushed on quite well. By adding a drop or two of water I could thin it just like when using turpentine to dilute oil. I still needed turpentine or spirits to clean the brush, or I could also work with water miscible oils to avoid that. I found that all of my oil paints worked well, including the slow drying pigments. In fact, even the slowest drying paint I have, Winsor and Newton's Cremnitz White which is lead white in safflower oil, dried much faster than usual. Typically the paints were dry to the touch in 30 minutes or so, instead or 1 or 2 days, and so the layers could be painted over in a very short time.

Why does the oil dry so fast? As clearly as I can reason, it is held in suspension like what happens using oil and wax, and this allows the oil to oxidize more quickly while coating it in the dried emulsion.

My typical process of painting is to lay down a thinned layer of paint and diluted MC as an underpainting tone, or grisaille. After that dries, I add a layer of paint mixed with an undiluted MC solution. On top of that is an oily layer that may not contain any MC at all, or very little. The "fat over lean" rule still applies in terms of layering, so no previous layer should have more oil content than the one you are adding.

I found that when painting on an oil surface with a diluted solution, for instance on an oil primed ground, the medium can bead up somewhat. Adding a little linseed oil and/or resin to the solution will make it spread better in that case. You can also add a small amount of honey, but not too much or it will become sticky. Also, when using MC in large doses, it can cake up if you overwork your brushstrokes.

Glazing Layers:
This medium is excellent for a glazing technique, since adding it to paint makes it more transparent. It dries quickly, and clear. One aspect of MC or CMC is even soon after it dries, it can be reactivated with water. As such, when painting over a dried layer use the solution itself mixed with the paint and do not add extra water. A soft brush with a soft touch will keep the paint from lifting in the layer beneathYou can also mix in an appropriate oil medium of your choice, or one that contains resin to help isolate the layer beneath. If you add more oil that will slow the dying time. Once the oil has completely dried the surface is impermeable.

Suppliers:
The Sennelier bottle was 8 ounces for about $24 Canadian. I have not been able to find that brand anywhere else except at some stores in Europe. There is a company called Lineco that sells it in smaller bottles. Several raw pigment suppliers carry it, like Natural Pigments or Kremer (sold under the Tylose brand name.) A one pound bag is inexpensive. I found CMC at a local pottery supplier. Studio Products has a CMC product called Amber Gum, which I have not yet tried out.

It is very economical, since as I mentioned above a tablespoon made 4 ounces of solution. I suspect this bottle of powder will last for many years.

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References and Resources:
http://aic.stanford.edu/sg/bpg/annual/v01/bp01-04.html
http://www.chemistrystore.com/Using%20Methylcellulose.htm
http://www.paperbookintensive.org/2whit.html
Natural Pigments
Kremer USA (Tylose)
Studio Products