Sizing Paper

Sizing paper in the context I’m going to discuss isn’t about measuring the size, but rather applying a ‘sizing’ solution (usually some sort of animal glue and alum) to paper with a brush to strengthen it. This maybe doesn’t sound very exciting and artistic, but it is a vital step in many artists’ practices that is largely overlooked by art historians. Without sizing the paper, pigment and ink would bleed, run and blur. Sizing the paper both strengthens it and allows the pigments to be applied with greater control. At the end of this post, I will explain how I make my own sizing solution from animal glue and apply it to paper. Once the paper is sized and mounted, I can then in following posts, discuss gold-leaf and mineral pigments.

A Japanese print by Utamaro (1753-1806) shows the stages of print making and ‘sizing’ paper is shown in the bottom left. A woman is applying the sizing solution, diluted with water, with a wide brush to the paper. The paper is then hung up to dry before being used on the woodblocks for printing.

Kitagawa Utamaro, 'Cultivation of Brocade Prints', circa 1803, British Museum

An example of how art historians can sometimes get it completely wrong when it comes to sizing, is the case of the Ming dynasty artist Xu Wei (1521-1593). Xu Wei was famous for his wild and expressive ink paintings that influenced later modern Chinese painting. Below is his painting of grapes in the Palace Museum, Beijing, showcasing his splashed-ink technique (pomo 泼墨).

Xu Wei, 'Grape Vines', late 16th century, Palace Museum, Beijing

Anyone that maybe has tried sumi-e or shuimo hua painting (traditional ink painting) would know that if you tried to achieve this watery, splashed-ink technique on the paper, it will just bleed into a blobby mess. So how was Xu Wei able to create such watery pools of velvety ink with such control? Some art historians have argued that he put glue in the brush with the ink. Many years ago I tried this technique but it simply ruined the brush and it had little effect. Only later did I discover that actually Xu Wei simply used ‘sized’ paper: the same thing that is being shown in the print above by Utamaro.

Knowledge about sized and unsized paper is still very important to those in the industry. Many years ago when I lived in Beijing, I would often visit a paper shop in Liulichang street. The owner when checking new stocks of paper, would hold a sheet below his face and allow a thin thread of saliva from his mouth to drop onto the paper. I didn’t understand at the time what he was doing, but I now know he was checking if the paper was sized or not. If it was not sized, his saliva would bleed and run on the paper; if sized, it would stay as a near-perfect circular droplet. In China, following the tradition of Qi Baishi (1864-1957), many prefer this unsized paper (the term is raw Xuan paper or sheng xuan zhi生宣纸) perfect for creating uncontrolled and expressive ink

blotches. But for controlled work, with fine lines and details etc, one may prefer ‘ripe xuan’ paper or shu xuan zhi (熟宣纸). For my ink paintings of cats, I always prefer ‘ripe xuan’ paper.

Sizing paper is also key for later mounting it onto a wood panel, which I then apply gold-leaf onto. To size my own paper, I make my own glue made with boiled rabbit skin (sorry vegans and animal-lovers, but this is just typical artistic practice used for centuries and starch glue won’t work as it dissolves). Rabbit skin glue can be acquired either online or art supply shops.

1) Making Glue (Nikawa) or Sizing Solution (Dosa)

In Japanese terminology, glue is called nikawa (膠). It is durable and elastic, although it loses flexibility with age. Mixed with alum, it can be a sizing solution called dosa (礬水). But essentially, they are the same substance. Alum is not available to me, so I use nikawa with a bit more water as a sizing solution and it works for me.

First, put a teaspoon of rabbit skin granules into a pot with water to soak for a few hours or overnight. There is no exact amount of water or glue to use; it comes with experience, and everyone has their own ratio depending on how much they want to make. I usually just add water as I go to get the right consistency. Eventually you want a thin broth-like liquid glue. It should feel sticky on your fingers.

Once the animal glue granules have been left to soak in the water for a few hours, it will expand, but not fully dissolve. To dissolve it, you now need to put the pot in a larger pot with water over a stove. It is a bit like making a cream or chocolate sauce, you don’t want it to boil directly, or it will burn. If it burns, the glue won’t be sticky, and also your kitchen might smell like a medieval apothecary. Once it is dissolved you can put the glue into a jar. In winter it may solidify, and you need to heat it gently again in a bowl of hot water, but every time you re-heat the glue, it will lose its strength a bit. It will also naturally lose its strength over time, so don’t keep it too long in the cupboard.

2) Applying the Glue to Paper

Once you have the glue, you can use it as a sizing solution. Alum should be added (as a preservative), but I never had any available and used it perfectly without. If it’s too thick, I add a bit of water. I use a wide hake brush to soak the paper (which you can put on a board) with the glue. I then let it hang to dry. It will wrinkle a bit, but when it dries, you can apply water again and mount it on a wood panel when it will stretch and become perfectly flat again. Sometimes you can also just iron the paper if its too wrinkled.

3) Mounting the Paper on Wood Panel

Once the paper has been sized, you can either let it dry to use later, or I find, you can put it straight onto a wood panel while the glue is still wet. Make sure if you are using Japanese washi paper, that the smooth side of the paper is on top, the rough part should be beneath. Use starch glue this time with your fingers around the edges of the wood panel. Once you place the wet pliable paper on top of the panel, use a towel or brush from the centre gently pushing outwards any air-bubbles, then press the paper onto the sides with starch glue and let it dry for a day.

Once its dry, the paper will stretch slightly and be flat with no wrinkles. You can then trim the edges and fold the corners with starch glue. You can either paint directly onto the paper, or they are ready to be applied with gold-leaf! This glue is also the binding agent used in natural mineral pigments, and it is also applied on top of the gold leaf to seal it and make it paintable. But that is for another post.