Gesso coating or paint primer?

[stagfoot]

Are you just using adhesives to adhere canvas to a support or are your concerned about using them as a sizing medium?

Michael Skalka, Conservation, National Gallery of Art, Wash, DC

I’ve been sizing my canvases with acrylic medium, I reason this should be perfectly archival, but if it isn’t, I’d be very interested to hear your views on the matter

[Michael24]

I’ve been sizing my canvases with acrylic medium, I reason this should be perfectly archival, but if it isn’t, I’d be very interested to hear your views on the matter

I am assuming that you are preparing a canvas for an oil painting. If so, acrylic medium is fine for sizing a canvas. Again, assuming that you are following the acrylic sizing with an acrylic dispersion ground (acrylic gesso) and applying it according to the manufacturers directions.

The biggest problem with oil paints on acrylic prepared canvas is that artists don’t put enough ground layers on to stop oil penetration. It may look good with just one coat, but in many cases that is not enough. The directions provided by the manufacturer are a good start. They usually test the oil penetration of their grounds and recommend how many layers to put on a canvas in order to stop the penetration to the canvas level.

If you are painting in acrylic, the acrylic sizing is not really needed. You can just apply the acrylic gesso directly to the canvas.

Hope this helps.

Michael Skalka, Conservation , National Gallery of Art. Wash. DC

Michael Skalka, Conservation Administrator
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[JamieWG]

One more question….(Yeah, right!)…..What about the newer polyester canvases that have emerged in the marketplace? What do you think of them, Michael? Are they in fact a more archival surface for oils, either on stretchers or glued to a support, with an acrylic gesso ground? Would this type of canvas need sizing too?

Many thanks,
Jamie

Hudson Valley Painter[/url]
Hudson Valley Sketches -- Reviews/Lightfastness Tests/Art Materials [/url]
One year from now, you'll wish you had started today.

[Michael24]

One more question….(Yeah, right!)…..What about the newer polyester canvases that have emerged in the marketplace? What do you think of them, Michael? Are they in fact a more archival surface for oils, either on stretchers or glued to a support, with an acrylic gesso ground? Would this type of canvas need sizing too?

Many thanks,
Jamie

No, please keep the questions coming. Polyester canvas: If you mean the 100 percent polyester canvas, these seem to show great potential for very long-term performance. The cotton poly blends are not recommended because each type of fiber behaves differently.

We think they are more archival for oils because of the oxidation factor so common to oil penetrating organic material. The one drawback is that lots of people find them aesthetically unpleasing. The weave texture looks a bit too uniform and artificial. With enough acrylic dispersion ground on them, that issues goes away. I might still look toward sizing just to avoid the oil staining that could occur if medium penetrates the ground. Who knows over time the oil might do something to the polyester, but we are talking about a very long time. Yes, I still would make every effort to keep oil from getting to the canvas.

Our feeling is that a polyester canvas adhered to a Dibond panel with a well prepared ground layer is a wonderful, extremely long lasting support for oil painting.

More later…

Michael Skalka, Conservation, National Gallery of Art, Wash. DC

Michael Skalka, Conservation Administrator
Subscribe to: The Grammar of Color- a paint history newsletter. Send an e-mail to: [email protected] with your name and a current e-mail address.

[JamieWG]

Michael, thank you for that reply. I’m going to try a roll of that polyester canvas pre-primed as soon as my current roll of cotton runs out. (Won’t be long! ) I’ll add additional gesso layer(s).

Here’s the question I posted before, but don’t think you saw it before it got buried:

Michael, I hope she sees it too, but even if she does/did not, many of us benefit from these conversations, even if we don’t all post to say so!

And speaking of archival properties….
If I use floor polyurethane on a plywood panel, will acrylic ground/gesso adhere to that oil-based polyurethane? If I plan to use the acrylic ground, am I better off with water-based poly? Most likely I’d adhere canvas with PVA…will that hold to the oil poly?

Often I paint on unstretched, primed canvas. Since the paint is not directly on the board, can I then adhere the canvas to MDF or hardboard if I seal it first with the oil-based polyurethane, without worrying about SID?

Jamie

Hudson Valley Painter[/url]
Hudson Valley Sketches -- Reviews/Lightfastness Tests/Art Materials [/url]
One year from now, you'll wish you had started today.

[sillk]

i was sitting here thinking what a great cache of info this thread is, and how fantastic it would be to have a book full of answers like these to the archival question. and then i thought, maybe there is! somewhere…

so is there?

and if there isn’t, i nominate Michael to write it.

[stagfoot]

If I use floor polyurethane on a plywood panel, will acrylic ground/gesso adhere to that oil-based polyurethane? If I plan to use the acrylic ground, am I better off with water-based poly? Most likely I’d adhere canvas with PVA…will that hold to the oil poly?

Often I paint on unstretched, primed canvas. Since the paint is not directly on the board, can I then adhere the canvas to MDF or hardboard if I seal it first with the oil-based polyurethane, without worrying about SID?

Personally I don’t think acrylic gesso would stick to an oil-based polyurethane.
I don’t know if PVA would stick to it either, I suppose you could try a test strip and see how that works.

Is it the canvas you want to seal here, or the board?

Hope you don’t mind me asking but why do you want to use polyurethane? What advantages does it give you? :confused:

[stagfoot]

No, please keep the questions coming. Polyester canvas: If you mean the 100 percent polyester canvas, these seem to show great potential for very long-term performance. The cotton poly blends are not recommended because each type of fiber behaves differently.

What about all those other synthetic fibres, as I’m having bit of difficulty finding a decent weight of polyester.
I’ve found some promising looking acrylic canvas, but it’s a bit pricey and I don’t know if it would be any good anyway.

[Einion]

Are you just using adhesives to adhere canvas to a support or are your concerned about using them as a sizing medium?

Hi Michael, I don’t like to paint on stretched fabrics so I’m interested in sizing only theoretically

I use PVA to bond canvas (usually cotton duck) to untempered hardboard if I want the weave texture but generally I prefer a smoothly-sanded acrylic ‘gesso’ surface.

Einion

Do you know if your colour is off in hue, value, chroma... or all three?

Colour Theory & Mixing forum WetCanvas Glossary Search Tips Advanced Search Acrylics forum Acrylics - Information Kiosk

[Einion]

FWIW I got samples of the available polyester fabrics on one of my last trips to London and although in terms of longevity it seems to be a clear winner – for oil painting it doesn’t respond to changes in humidity and hence doesn’t promote cracking – the texture is very mechanical and I probably wouldn’t want to paint on it, but it might suit certain kinds of very clean, tight work.

Besides, if one is a professional or very serious amateur I think oil painting should really be confined to rigid supports anyway since they are so much less prone to problems and there so many good options to choose from these days – if you’re addicted to the texture of fabrics just bond it to a rigid substrate.

Einion

Do you know if your colour is off in hue, value, chroma... or all three?

Colour Theory & Mixing forum WetCanvas Glossary Search Tips Advanced Search Acrylics forum Acrylics - Information Kiosk

[JamieWG]

Is it the canvas you want to seal here, or the board?

Hope you don’t mind me asking but why do you want to use polyurethane? What advantages does it give you? :confused:

I would use it to seal the board. It protects it from changes in humidity, and stops the support induced discoloration that can result from a water soluble sealer. At least, this is my understanding. Michael, please correct me if I’m wrong. Golden also makes a product that can be used for that purpose according to their website. But if the acrylic gesso, or PVA to hold on canvas, will not hold to the polyurethane, I guess I can’t do that. I cannot get into a long drawn-out process of lead grounds, etc. I just want to paint, and I go through waaaay to many panels and canvas, especially during plein air seasons, for anything remotely resembling an “ordeal”!

Jamie

Hudson Valley Painter[/url]
Hudson Valley Sketches -- Reviews/Lightfastness Tests/Art Materials [/url]
One year from now, you'll wish you had started today.

[MarthaF]

I am new to oil painting. I am using acrylic gesso to glue down cotton canvas to masonite panels. Then I use 2 coats of gesso on top of the canvas. Is this okay? I am confused about glueing, sealing, priming, and gessoing. Would someone care to define these words? Thanks!

[Michael24]

Sorry, was away a bit – I will get back to answering tomorow or Monday morning.

Michael Skalka

Michael Skalka, Conservation Administrator
Subscribe to: The Grammar of Color- a paint history newsletter. Send an e-mail to: [email protected] with your name and a current e-mail address.

[REDart]

Michael24

Thanks for taking the time to answer all these questions. Maybe we need a tech. forum. I am looking for a clarification. Did you mention that you should use an acrylic size under an acrylic gesso for oil painting? I have never heard that before.

It is very difficult to get good information about this stuff as most of what I read comes from people trying to sell their own products or artists that won’t use anything that wasn’t in use 200 years ago.

Thanks

[Michael24]

What about all those other synthetic fibres, as I’m having bit of difficulty finding a decent weight of polyester.
I’ve found some promising looking acrylic canvas, but it’s a bit pricey and I don’t know if it would be any good anyway.

It is very difficult to say which canvas is acceptable. No standard exists for how the fabric is sized in the factory or what sort of surface it has. I will have to look into acrylic yarns a bit more to give you better info.

Michael Skalka
Conservation, National Gallery of Art

Michael Skalka, Conservation Administrator
Subscribe to: The Grammar of Color- a paint history newsletter. Send an e-mail to: [email protected] with your name and a current e-mail address.

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