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Old 08-05-10, 04:35 PM
briancorll briancorll is offline
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Default Unreceptive Areas of Gesso

I'm working on a new painting on a commercial panel. Though it comes already coated with gesso, in the past I have added several coats of my own gesso. I'm finding areas that simply won't accept the paint. Just very small areas, but enough to give me fits. Is there hope for this panel or should I scratch it and refinish it with my own gesso ? BTW, the panels I'm using are Panelli a Gesso from Italy. A friend of mine who trained in Italy says the Italians use potassium carbonate, not calcium carbonate, in their panels. Is it the panel that's really causing me trouble or should I look to my emulsion ? (Just plain 1:1 egg water). TIA.

Last edited by briancorll; 08-05-10 at 04:40 PM.
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Old 08-05-10, 05:14 PM
briancorll briancorll is offline
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Hmmm...I'm wondering if it could have been the golden ochre imprimatura that I put over the panel first. At any rate, I washed the panel clean and I am starting over (there goes a morning's work !), but I would still like opinions on the panel and ground. Any opinions on the Panelli a Gesso, qualitywise ?
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Old 11-05-10, 01:26 PM
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PhilS PhilS is offline
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Brian,
Gessoed panels are, and apparently will continue to be, a problem. I was able to locate a supply of untempered masonite (hardboard) panels- enough to keep me going for a couple of years. My gesso mix is from Natural Pigments. So far, so good. I like preparing my own panels. It's less expensive for one thing, and I know what I'm getting. No adhesion problems or pinholes. If you do decide to make your own panels, I would suggest avoiding Fredrix Dry Gesso mix. I discussed in an earlier post problems I've had with Fredrix (the rabbitskin glue wouldn't dissolve). I contacted the company several times and got no reply, so they've lost a customer.
Can't advise you on Panelli - I'm unfamiliar with them.
Good luck!
Phil
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Old 12-05-10, 06:49 AM
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UBI UBI is offline
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Hi
1) Pannelli a gesso isn't a sufficient information because it simply mean "gesso panel", if you have information about manufacturer or dealer it could be a good start.
2) Never heard of use of potassium carbonate for grounds; in Italy is more traditional to use calcium sulphate bihydrate ( the real gypsum) instead of calcium carbonate.
3) Traditional grounds made with RSG and both calcium carbonate or calcium sulphate have great absorbency ( more or less depending on filler : glue ratio), so the behaviour you described is strange.
If I understand well you laid an imprimitura over the ground, this depending on the nature of the medium used change the absorbency of the whole, the only other thing I can argue is that the panel became dirt with some greasy substance.
4) I agree with Phil, homemade panels are best you can use.

Good luck
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Old 13-05-10, 02:59 AM
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Koo Schadler Koo Schadler is offline
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This is a handout I give in class when teaching tempera. #3, on rubbing down the panel with denatured alcohol, might specifically address your problem. Hope it helps.

Koo

FINISHING YOUR NEWLY PURCHASED, PRE-MADE, TRUE GESSO PANEL


For those who buy pre-made gesso panels, you may think you need only open the box, unwrap the panel, and begin painting. Not so fast! To make sure your panel will behave as it should, its best to begin with the following:

1. Become acquainted with the surface

First study the panel’s surface in raking light. Raking light is when you tilt your panel back and forth until light rakes across the surface and casts shadows that reveal pinholes, scratch marks and other imperfections. If you see anything that may interfere with your painting, circle it lightly with a pencil. Gently sand (preferably using a block) until the marks are no longer visible. Pinholes cannot always be sanded away, but sometimes slightly wetting and rubbing the surface will fill them in.

Most professional panel makers apply gesso with a spray gun. It is efficient, and creates a consistent surface, but also imparts a subtle texture. In raking light you can see this texture and may decide you’d prefer a smoother finish. Light sanding (about a 220 grit paper, again using a block), followed by gently rubbing the surface with moistened fingertips will create a traditional, ivory smooth gesso panel.

In short, become acquainted with the panel’s surface and make sure it is sufficiently smooth for your purposes.

2. Bevel the edges

Are the edges and corners chamfered (have a slight edge to them)? If not, tilt your sanding block 45° and give them an angle. This prevents chipping.

3. Degrease the surface

Next, gently rub the surface with a cloth dipped in denatured alcohol. This will remove greasy fingerprints or other unknown containments that could make the surface unreceptive to paint.

And now, onto the fun part: painting!
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Old 17-05-10, 11:17 AM
artistcb artistcb is offline
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Quote:
Originally Posted by Koo Schadler View Post

3. Degrease the surface

Next, gently rub the surface with a cloth dipped in denatured alcohol. This will remove greasy fingerprints or other unknown containments that could make the surface unreceptive to paint.
Would you also do this to an Ampersand "Clayboard"? Ampersand promotes these for tempera and although I am not planning on using these continually I would like to practice on them instead of the panels I've made.
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Old 17-05-10, 03:55 PM
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Koo Schadler Koo Schadler is offline
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I think it would probably be a good idea for clayboard as well, to wipe the surface with denatured alcohol.

Clayboard, as you suggest, is fine for practice, but in the long term a true gesso board is best. From what I understand the binder in clayboard is an acrylic polymer. The addition of clay does make for a more absorbent ground than the acrylic gesso you find in most art stores (and absorbency is what egg tempera paint works best with). Nonetheless I find that egg tempera slips around a bit on clayboard, and does not have the same, wonderful working properties atop acrylic gesso and clayboard as it does on top of true gesso. And in the long run, any ground with acrylic polymers is not as archival for egg tempera as true gesso. So if you work atop the clayboard, and become frustrated with your paint (i.e. find that the layers aren't building readily, you get too much lifting, etc) make sure you try egg tempera on true gesso before blaming it on the paint!
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Old 17-05-10, 05:02 PM
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UBI: "Panelli a Gesso" is actually the product name,and is carried by the big US online dealers like ASW and Jerry's:

http://www.aswexpress.com/art-supply.../0059766000000

I got some a while ago and found them totally unsuitable for tempera, because their surfaces were randomly pitted and gouged, even beyond the texture that one would expect from their description.

Which brings up my main question: Brian, what do you mean that the panels are not accepting paint in some areas? In my experience, there are 3 ways that can happen:

1) A substance (oil, dirt, acrylic glue, etc.) is on a spot of the surface and will not absorb the paint. This is usually obvious when a wash is put down, and a dirty spot that was invisible remains white and becomes highly evident and defined.

2) Pinholes or scratches will not accept paint. Who knows why scratched gesso doesn't suck up paint like smooth gesso, but it happens. Most maddening in my experience are micro-pinholes, which are almost impossible to see before painting, and result in what appears to be sparkling dust on the panel, when in reality they are very small, shallow pits that refuse to accept paint even when multiple layers are applied.

3) The gesso just has something screwy in it. This is pretty rare, in my experience, with anything that is properly labeled. I suppose it could happen, but I'd imagine it would have a consistent effect over the entire panel. I just used my "Panelli"s for practice oil sketches.

And then, of course, there's Lifting, which is a whole 'nuther animal.

Catherine, I concur with Koo that degreasing a commercial panel (especially claybord) is a good idea in all cases. I will admit that I don't do that, but a) I accept the consequences, and b) I usually do a wash over my panel as a first step so I'll see right away if anything mars the surface. I also agree that claybord is OK for playing around if no other option is available, but its not a good thing to stick with and is more susceptible to lifting while working, especially with wetter broad strokes.
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Old 18-05-10, 01:37 AM
artistcb artistcb is offline
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Quote:
Originally Posted by Koo Schadler View Post
So if you work atop the clayboard, and become frustrated with your paint (i.e. find that the layers aren't building readily, you get too much lifting, etc) make sure you try egg tempera on true gesso before blaming it on the paint!
Thanks Koo, we shall see what happens! I won't be using it again after this. I just wanted a surface that I can practice technique and strokes and such that won't bother me if I make a mess of it.
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Old 18-05-10, 01:40 AM
artistcb artistcb is offline
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Quote:
Originally Posted by JeffG View Post
Catherine, I concur with Koo that degreasing a commercial panel (especially claybord) is a good idea in all cases. I will admit that I don't do that, but a) I accept the consequences, and b) I usually do a wash over my panel as a first step so I'll see right away if anything mars the surface. I also agree that claybord is OK for playing around if no other option is available, but its not a good thing to stick with and is more susceptible to lifting while working, especially with wetter broad strokes.
Thanks Jeff, and I like your idea of doing the wash over the panel as a first step. Do you do this in a color or just super lightly and wipe off or ?????
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