Wednesday, May 13, 2009

Preparing Large Canvas

I apologize that I don't have any exciting images for this post, but I wanted to quickly share some thoughts on painting supports.

Recently, I have become dissatisfied with most pre-made canvases. Frequently I've encountered problems including very loose canvas, canvas with thousands of pinholes, stretchers that are warped, and rough-textured priming. On top of this, most pre-made canvases are primed with acrylic priming, which may not be the best ground for an oil painting, and many oil-primed canvases are made with a ground that contains zinc, another no-no. The best pre-made surfaces I've found are not cheap.

Therefore, I decided to take the matter into my own hands!

Solid supports, such as wood or copper, don't move and therefore have an advantage over canvas, which flexes and therefore can exacerbate weaknesses in the paint layers. However, the weight of such supports can prove problematic at larger sizes, so I decided to use a polyester canvas on my large (4ft and larger) paintings. The word 'polyester' certainly doesn't bring to mind anything fine-art related, however I feel it will be a very sound support for my paintings. The reasons are as follows:
  • Polyester does not react to moisture in the air or temperature changes, therefore it will not have problems that paintings on linen and canvas do when they expand and contract with those changes. This canvas will not loosen or require future tightening!
  • Mold does not grow on, nor do bugs eat polyester.
  • Oil itself does not cause polyester do rot, as it does natural fibers. So, even if some oil makes it through and touches the canvas (like would happen if there was a pinhole) it will not affect the support negatively.
The only thing that will apparently deteriorate polyester is UV light. So long as the canvas front is covered in paint, and the back is protected from light, polyester should outlast other fabrics as a support. Ideally, I would glue the polyester canvas to a wood panel, but again size right now is preventing this.

I happened to find artist's unprimed polyester at Utrecht in a sample pack, and I personally liked the tight weave. There were no pinholes to be seen and the canvas is very smooth. I expected the canvas to be flimsy and stretchy (because I was thinking of polyester clothing) but it was rather very much like a regular cotton canvas.

With the assistance of my apprentice and a friend at the studio, Ron Smith, we stretched a 4' x 6' canvas with the polyester. It seems easier to get the fabric to be very tight than it does with linen or cotton. I have a canvas Ron stretched that is so firm it nearly feels like a panel, and my large canvas is like a drum, *literally.* I love it.


I primed a couple smaller canvas with oil primer alone, but on the large one I decided to experiment with some PVA Size. It is not neccessary to size polyester before oil priming, but it does help the primer to go on smoother. Without the size, the fabric really seems to 'grab' the primer. I used Gamblin's size, but am interested in trying others. I use PVA size as opposed to rabbit skin glue because it also does not react to temperature or humidity.

For my primer, I used Windsor and Newton's oil painting primer because it does not contain zinc (which can cause cracking/delamination) or lead (which is a health hazard.) It is a titanium/alkyd primer which dries in 24 hours. It does smell quite strong, so use in a well ventilated area, ideally that you can vacate for some time after application. Again, I am interested in trying some other oil primers, but I will always steer clear of anything containing zinc.

The resultant layer of primer is very scratchy and rough, so I used a palette knife to smooth each layer. I have yet to paint on this surface since I just finished it up today, but I will report back once I give it a try.

It does take some time to prepare a canvas this way, and nearly always would rather have that kind of work done for me, but this way I am confident that I am doing everything I can to make sure my work is archival and therefore worthy of purchase, and hopefully this will also be the most enjoyable surface to paint on!

8 comments:

Anonymous said...

Very interesting. I'm a painter interested in using polyester as well. However, the PVA kind of confuses me. Polyester not only doesn't need a size, but since polyester is not absorbant, doesn't it seem like the PVA would create a layer of size rather than penetrate the fibers? Did the PVA dry glossy?

Bethany said...

This is all very scientific. What I love about writing: open Microsoft Word (or Scrivener). I'm done preparing my medium!

Lacey said...

Bethany- Word! I'm jealous. I am not excited by stretching canvas, grinding pigments, any of that stuff. Clean-up is also a pain, if only because it steals some of the painting time. Boo!

Anonymous... I *know* that polyester is not absorbent, yet it seems to behave that way to some degree, so I am not sure what is really happening. When I applied the ground with no size, it didn't slip around on top of the canvas like you would expect with a non-absorbent/non-porous material like, say, plastic. It did appear to 'absorb' the ground and I didn't get much coverage from each brush-load of primer.

The PVA size did not dry glossy. I'm not sure if there was any absorbing going on or not, but it did seem to affect the application of the ground slightly, making the polyester 'grab' the primer a bit less.

Please note that none of this, the sizing or the priming, caused any tightening of the canvas, which is the only part that behaved as I expected.

Also, please note that I have never used the oil primer nor the PVA size before on any other material, so I have no reference point with them for comparison.

I hope this helps! Go get some polyester and let me know about your experience with it.

Christopher Adam Lessley said...

Be sure to denote the denier count of the polyester if its American vs. Chinese manufactured! I would recommend at least a 600/D or better denier count for longevity. Then again, 12 oz. cotton duck has lasted for hundreds of years in prime condition since it use as a painting surface...

Gabriel said...

Hey Lacey -

I left a comment on this posting a long time ago (yes, I am the anonymous poster asking about the PVA size, haha). Anyway, my question now is about the primer you use. I'm curious to know if you've used Gamblin's ground. I'm wondering this because I've only used gamblin's but I find myself going through the stuff damn fast and it's getting spendy. I see you use W&N's primer. Does W&N's seem to go far? I know if I prime a 4x6 canvas with gamblin's, I usually use up about 1/3 the can, sometimes half...In only one coat! I appreciate your time, thanks a lot.

By the way, I bought some polyester from utrecht, and I love it. Thanks for the recommendation

Lacey said...

Gabriel-

Sorry for the delay! Been busy...

It's been a while since I primed this canvas, but I think your estimation of 1/3 of the can sounds about right. Perhaps this is the feeling of the poly being 'absorbent' that I mentioned. I do think that using the PVA size helped that, though you are also spending the $ on the size so I am not sure if that makes it overall less expensive.

Unfortunately, I have not used the Gamblin product, nor have I used an oil primer on a natural fiber canvas, so I am not able to truly compare for you. Sorry I am not more helpful.

[Edit: Now that I think about it, I primed the canvas that I am currently painting on with 3 coats of the W&N primer, and I am sure I have some left at the studio. I can check how much I have left, and I can also try and keep track of how much primer I use next time I stretch and prime a canvas. Please feel free to email me or nag every now and then. I tend to forget to email or report these things, but I am really not bothered by repeated reminders as I intend to share info!]

Christopher Adam Lessley said...

For comparison, on a 7 x 6 cotton duck canvas, I'd use a little more than 1/3 of one gallon of acrylic gesso, putting on 3 coats, using a typical house painter's 6" wide brush. Never have used any Gamblin products.

Simon S. Andrews said...

i'd recommend ditching the ripoff gamblin size and grounds - they are meant for organic substrates, and just throw some alkyd on the polyester... call it whatever... and you can control the absorbency by how you dilute the alkyd.