Cracking?

I'm engaged upon a bit of research - I've always been wary of paint cracking, through failure to observe the fat over lean principle.  And yet, I've only ever had one oil painting crack - and that was because of ill-advised placement of Ivory Black.<div> </div><div>I've painted on top of oil paint, usually to improve (I hoped...) a composition, or liven a picture up that had sunk into the canvas a bit.  No cracks...</div><div> </div><div>Using the usual methods these days - canvas or board, sized and primed with acrylic gesso, oil paint in layers on top: have YOU ever experienced cracking of oil paint?  Or is this - as I begin to suspect - a phenomenon of older painting methods and materials, rather than of modern oil paints, solvents and oils?  </div>

Thanks for resuscitating this thread with those useful and interesting links. I shall explore them in more detail over the holiday (I've got quite a lot to look into already, from various points on these threads!). Linseed oil does indeed get harder over time - if it's on a flexible surface, that's likely to create an obvious problem; you're quite right of course that there are few oil paintings of any age which don't show some signs of cracking, especially though not invariably if they're on canvas. The old masters didn't always use Linseed, of course ... and I suspect some degree of cracking might have occurred whatever they'd used. I have read that sun-thickened Linseed oil or Stand oil - there's a good deal of confusion about these terms - are less likely to crack than raw Linseed: but ... I can't pretend to know. Liquin, being an alkyd medium, suits me well too - you have to wonder what the long term result of using it will be, and until posterity tells us we can only guess. Ironically, some fake cracking as a sign of age........ you can even buy a craquelure medium: why, I can't imagine, unless it's for a film prop. I'm comforted by the suggestion that acrylic paint will survive in better condition, since it's my other main medium; and I HOPE it's true... Certainly my 50 year old paintings in acrylic and in oil are showing no sign of deterioration yet: I wish the same were true of me........

I hesitate to say, Syd - it might depend on where you stored it, or it might have been the priming of the canvas....... looking around me, I find that most of my paintings are on board; only a few are on stretched canvas, these aren't very big, and actually I've never entirely trusted stretched canvas and so deliberately restricted the size: I have one larger one, in a private collection (in a centrally heated building) and so far as I know that hasn't cracked - but then it's only around 35 years old. Finding the reason why a picture cracks and crazes can be difficult - and most of the time it's guesswork. But I'm sure it wasn't your technique at fault! Perish the thought. I think - on balance - that if I were trying harder to sell than I currently am, I'd stick to either stretched linen, or possibly even polyester, or, preferably, canvas stretched over board. Provided it's framed, by the way, Dalerboard is hard to beat as a long-lived surface which is also rather good to paint on; whether you could sell a painting on Dalerboard to the more snooty galleries, though, I seriously doubt. To avoid cracking generally - I'd recommend (if using thicker paint anyway) not too much extra oil; no artificial drying agents; a minimum of solvent in anything other than the base layers; and hanging the painting in a room you live in - ie, one that's reasonably warm but not heated to greenhouse proportions or freezing cold either - and with natural light. Oil paintings don't like the dark: certainly not in the long drying period, and not, I think, thereafter either. I also suggest 'oiling out' - applying a very, very sparing layer of Winsor and Newton Oil Painting Medium or equivalent when the painting's dry, being sure to wipe off any excess (not that the excess would hurt the painting much, but it would look unsightly and might dry in globules - lovely word, 'globules'...). The very worst thing you can do with a painting, always provided your technique in painting it was sound, is to varnish it too soon: you can oil out as soon as it's dry to the touch, but an early application of varnish is a very bad idea and will almost guarantee cracking which is virtually impossible to repair. And we know what Erebus would say, don't we.......? Stick to acrylics.....

Report back, Mats - I can just about see the logic, although it's not a risk I'd have run to be quite honest..... but I'll be fascinated to hear how your acrylic varnish affects, or does not affect, the painting in one or two years' time (always assuming I'm still here myself of course). I don't quite see this working, though - because the issue is that the oil paint takes a long time to dry right through, so it continues to move, contract and settle. If you have a film on top of that, which dries but remains fairly soft, as acrylic varnish does at least in comparative terms, it's bound to be drying at a different rate depending on how soon you apply it - even acrylic varnish doesn't dry totally immediately. There is also the issue that a water-based varnish may not sit happily on an oil-based paint - any more than acrylic paint will adhere to an oil-based primer or oil paint. Still, you've obviously given this thought and have presumably taken all that into account. I would anticipate that if there is to be an adverse reaction, it's likely to happen fairly quickly: so your experiment should yield its result within 12 months, in theory. I wish you luck with it, but if you wanted a temporary varnish for immediate display purposes, there's always Retouching Varnish - I don't use it, or hardly ever do, but it would seem to be a lot safer.

You're probably right that there's a multiplicity of causes - with the added complication of bad luck: sometimes, a canvas will sag, however well it was stretched, primed, and nailed to the stretcher; sometimes paint will crack even when you think you've followed all the procedures properly, and indeed may have done. I suspect all we can hope to do is minimize the likelihood of cracking and crazing occurring - by careful use of solvents and oils, management of the ambient environment, being particularly careful of very old paintings - and so on. You say something interesting there (well, it's all interesting, at least to me!) - that paintings as it were settle down: paint expands, then contracts, then achieves stability. Two things arise from that - one, that the damage, whether visible at the time to the naked eye or not, probably occurs early and only gradually gets worse (eg through embrittlement, or movement in the support, or both), and two that oil paint is actually very strong stuff - it can take a lot of abuse, as for example Picasso's Weeping Woman did when it was stolen, found in a house by building workers who didn't recognize it as a valuable painting, and, basically, threw things at it in their lunch-break (bits of sandwich and bread-rolls, as I remember!). So one needn't be put off oil painting by the fear that it WILL inevitably crack: we have enough ancient oil paintings, centuries old, still in good condition, to prove otherwise. Keep us informed about your experiment, anyway.