A Blog About Oil Painting

Preparing Linen - A Short How-To Guide

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For the past few years I've been preparing my own linen and painting surfaces, for a fraction of the cost of buying rolls of primed linen or ready-made canvases.

It's easy to learn and I think it's something that every artist should try for themselves. All you need is space, time, and patience. I've written this post to document my own experiences and show you how to prime a canvas.

Of the several types of canvas that can be used as a painting support, linen and cotton are the most popular. They typically have the same plain weave, although cotton duck is heavier and more tightly woven, and they are both prepared in the same way. In the example shown here I'm using linen, but the same process can be used for cotton canvases or those made from any other type of natural fiber.

Linen

Let's start by looking at some linen. 

Close up of some linen

Raw portrait grade linen

The Belgian portrait-grade linen shown above costs about $30 per yard for a 54" wide piece. This is Dick Blick portrait medium (8.85oz). You can see that it has a tight weave and there are no holes visible between the threads. There's some random variation in the texture which is part of the attraction of using this as a painting surface.

Close up of some linen

Cheap linen from the fabric store

The Chinese linen shown here is a drapery fabric. It was bought at a local fabric store for $11 per yard (it is 53" wide). You can see holes between the threads. It had a lower thread count than the Belgian linen and the weave is less tight. It's also a lighter weight. There is a pattern to the weave which gives it a slightly mechanical look when it's finished.

Frame

Linen on a frame

The linen is prepared on a frame made from 2x4's with some cross bracing. The detachable legs make it easier to store.

Before starting I make sure the linen is not creased or wrinkled, and I will iron it if needed. The linen is then attached to a large frame with staples using a heavy duty stapler. It's important that the fabric is not stretched tight at this point (the linen is going to tighten up considerably when the size is applied), so I stretch it gently using my fingertips—just enough so that it starts to hold its own weight. The threads are lined up so they are parallel to and perpendicular to the edges of the frame.

I use a large frame because it's more efficient. It is made from 2x4's and has  cross bracing—everything is bolted together—and it has some detachable legs that screw into brackets on the underside. It measures about 4 ft wide by 7 ft long. On the large frame, I find that the first inch or so around the outer edge of the prepared linen can sometimes contain flaws such as wrinkles that no amount of stretching will remove. If you're preparing linen for a large painting make sure to bear this in mind.

If you don't have either the space for a frame or the tools to make one yourself you can also prepare your canvases individually on regular stretcher bars. Make sure to use medium to heavy duty bars as they need to be strong enough to withstand the tightening of the linen.

As you can see, I'm preparing this linen in the garage. When I work I'll have the garage door open for ventilation. If you're doing this inside you need to do it in a room with plenty of cross ventilation and, ideally, a door that can be opened to the outside. This is much easier to do in the spring, summer and fall when the weather is warmer!

Size Layer

Linen after sizing

Linen with two applications of PVA size. The water in the size has caused the canvas to tighten up.

All natural canvas used as a painting surface must be sized. Size is the term for a diluted adhesive that penetrates the fibers of the canvas, makes it less absorbent, and provides a buffer against oil paint. If you use acrylic gesso as the primer, sizing the canvas will also prevent something called support induced discoloration (SID).

I recommend using polyvinyl acetate (PVA) size—a mix of approximately 30% pH-neutral PVA adhesive and 70% water—which I use instead of rabbit skin glue (RSG). The main advantage of PVA is that it doesn't absorb much, if any, moisture from the atmosphere, so it is more stable than RSG. It is also much easier to prepare.

You can easily make PVA size yourself from white glue and water (you can buy it premixed, but it's about six times more expensive than making your own). However, a note of caution: Elmer's white glue is not pH neutral and is not suitable for use as a size—use a brand like Lineco instead.

Starting in the center of the linen and working outwards, I apply two layers of PVA size with a 2" house paint brush, carefully massaging the size into the weave of the linen so it is well absorbed and doesn't pool on the surface. The water in the size causes the linen to tighten up after a few minutes. The linen is allowed to dry between applications.

It is almost impossible to fill all the holes of the linen using PVA size alone, and putting too much size on the surface of the canvas can limit the adhesion of subsequent layers of primer. Yet, if you don't seal the holes in the linen, the primer will bleed through to the back side of the linen. Although this is not really a concern for the long-term survival of the linen (because it's buffered by the size layers) it can easily be prevented by applying a sealing layer.

Seal

Linen after sealing

After the final layer of size is dry,  the linen is gently sanded, then brushed free of dust. A thin layer of clear acrylic gesso is then applied, brushing it carefully into the weave of the linen with a large brush (I use the same 2" house paint brush that I use for the size). The clear acrylic gesso is prepared by mixing acrylic matte medium with marble dust and water. I've tried mixing these in various proportions and found that 4 parts medium, 1 part marble dust and 2 parts water works well. Adding too much marble dust makes the gesso brittle.

If you're lucky and you got the linen tension just right at the start, you may find that you can get through all the stages of preparing the linen without the need to re-stretch it.  If not, you'll need to remove all the staples and re-attach the linen to the frame, stretching firmly with canvas pliers. Staples are required every 3 inches or so. The stretching technique is identical to that used to attach canvas to stretcher bars, but on a larger scale. This part takes a little bit of strength, as well as some technique and practice. 

I've found by experimentation that it's OK, and perhaps better, to wait to re-stretch the linen until after this layer of sealer is applied. But if it looks very creased or wrinkled then re-stretch as soon as the size is dry.

Ground

With the linen now sized and sealed, it's time to get busy with the primer. Before going further, lightly sand down the linen and brush off any dust.

The next steps come down to personal preference: you could simply apply another coat of the clear acrylic gesso if you prefer a natural linen look; for a modern white canvas you can apply layers of white acrylic gesso. For oil-primed linen I would recommend starting with layers of white acrylic gesso before adding a layer of oil primer.

Linen with primer applied

The first layer of gesso always looks a little patchy.

The layers of white acrylic gesso should be applied thinly. Make sure that the gesso is worked in to the surface of the canvas so that the holes are filled. Adding a little water makes it easier to apply.

As you add more layers of primer the weave will become filled and the canvas will get smoother. If you prefer to work on an acrylic ground, then all you need to do is add more layers of gesso until you have a surface texture that appeals to you.

I prefer to paint on an oil-based ground so I apply at least one final layer of oil-based primer over the top of the layer of white gesso. I've found that a medium portrait texture linen is acceptable for painting with up to four layers of primer in total (the clear sealer, two acrylic, one oil). Finer grades of linen have less weave to fill in and will require fewer layers of primer.

I apply oil ground with a 1" bristle brush (one with fairly stiff bristles) as oil-base primer is too thick to apply with the same large brush used for the acrylic gesso. You may find it difficult to work with at first, but it's all in the technique. This short video explains how to get good coverage with the primer.

Brands of oil painting primer have different formulations. I prefer Winsor and Newton Oil Painting Primer for its relatively fast drying time (about 2 days at room temperature), and I also use Gamblin's Oil Painting Ground (which takes about a week to dry at room temperature). I find that adding a little solvent to the these primers (no more than 5%) makes them easier to apply.

Linen hung up to dry

Once the oil ground is tack dry I hang the linen up to finish drying. It saves a lot of space this way. The drying time of the oil-based primer depends greatly on the manufacturer and the temperature, yet they all have one thing in common: claims about drying time time are wildly optimistic. Don't attempt to sand down and repaint a layer of oil primer until you are sure that it's fully dry.

 When the canvas is finished it can be cut to size with scissors or a knife then stretched on your favorite stretcher bars or mounted on panels. Store any unused canvas rolled up around a tube with the primed side outwards.

Prepared linen

The oil primed linen cut to size and mounted on a panel. This is the cheap linen - not bad!