Paint cracking, or is it Gesso cracking?

[otto]

Within a few weeks of completing a couple of small ET paintings, I noticed hairline cracks forming almost entirely on the top edge of the panels. These panels had been prepared months before painting on them and no cracks had appeared on the unpainted panels all this time. Then, as mentioned, soon after completing the paintings, cracks appeared. I used very thin layers of paint. One thing I didn't do was "chamfer" or bevel the gessoed panels after they were prepared. And since the cracks are only on the top edges, and not within the center of the work, I'm thinking lack of beveling might be the problem. Or maybe too much rabbit glue in my size?? Do you all bevel your panels' edges? Anyone have this experience?

[Bert Congdon]

The paint is so thin, I can't imagine the paint cracking without the gesso cracking. My guess is the gesso. That was a big problem for me when I began. On the advice of my suplier, I add a glug of glycerin to the warm gesso, and that problem disapeared, never to return. I also add alum to tan it. Bert

[Dennis H]

Otto,
A couple of questions:
What material are the panels made of? Are they wood?
Are there a bunch or just a few?
Do they run pretty much in the same direction or go off everywhere?
(OK, sorry, it's a little more than a couple of questions...)
You said they only occur along one edge; do they extend very far inward?

Dennis

[PhilS]

Hmmm, this is a tough one.
I had a kind of similar problem years ago. I hadn't gessoed both sides of the panel and as the gessoed side dried and shrank, it warped the panel and caused little hairline cracks along the edges. In your case, having the cracks appear only on one edge, it may be something different. I agree with Bert, the problem is probably with the gesso, but I would be very careful about adding anything to the gesso. It could be the grain of the wood if you are using wood panels (as Dennis appears to be implying).
Untempered masonite and Fredrix dry gesso mix has worked fine for me for many years.
Good luck,
Phil

[otto]

Guys, Thanks for the responses. (I would have followed up sooner but I've not been online in a while.) All the panels were Artboard products, some being compressed wood fiber,some birch (I think) veneer on plywood. All made for gesso, according to their literature. I used Gamblin dry premixed traditional gesso, even distilled water. The one thing I actually measured myself was the RSG size. The dry rabbit glue is kind of old (What kind of shelf life does this stuff have?) My size could have been too strong a concentration. I just completed a painting on a panel, prepared the same way where I did bevel the edges prior to painting. No cracks so far. Could this be the answer? By the way, the cracks only go into the panel a quarter to a half inch and are irregular, twisting in shape. Thanks again.

[Dimitris C. Milionis]

I can only think that possibly Artboard products are cut into smaller pieces and this might cause a problem later on in its shelf life period when moister is applied in paint form; have you tried weting the surface to see if it occures, just a thought.

as for rabbit glue etc. good quality either ground or in sheets has no problem for several decades, thats the great value of the natural animal product, but if you look at Icons 200 yeas old you will see the same problem.

::: extract :::

"The panel was then passed on to the master who glued strips of flax or hemp canvas onto upper and lower borders of the panel and upon the longitudinal seams if the panel consisted of several planks. This was done to protect the gesso ground from cracking and peeling in the most vulnerable places. On ancient Icons, canvas cloth was glued over the entire face of the panel. Next the canvas covered panel was "grounded" or coated with a specially prepared priming which consisted of a mixture of chalk or alabaster and animal glue that was prepared from cooking pieces of hide with the gummy flesh side retained. Several coats of priming were applied, each being smoothed out with a special metal or wooden spatula (Klepik). Occasionally the palm of the hand was used to spread the gesso instead. After all the coats were uniformly dried, the master polished the gesso ground with pumice, continuously wetting it with water, and then finished it off with the stem of the horsetail plant."

::: end of extract :::

http://www.shipbrook.com/artsci/education/painting/IconsHistConst/icons1.pdf.

as you can see its always has been a problem, even for the russians in colder european climates

but gesso cracking will happen at some future time, its just to soon in your case

[otto]

I've worked on a few paintings, since the 'cracking' incident, that I beveled the edges of the gessoed panels, prior to painting. A couple months have passed and...no cracking. This appears to be good news since the previous cracking would have occured by now. I'll let you know of any further news. Thnx