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The Forum for Tempera Painting Issues Sharing the knowledge and experience of fellow tempera painters. |
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#1
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Several months ago, I made some gesso panels according to the instructions in Koo's wonderful book. They are lovely and smooth and seriously pissing me off.
My problem is that no matter what variables I change (i.e. egg quantity, water quantity, new eggs, paint color, etc) after 45 minutes to an hour the paint starts acting over-tempered. No matter how little egg I add to my paint piles, the paint is still over-glossy, streaking and lifting! It also feels unpleasant, as though the paint is over-tempered, although at this point I am using next to zero egg. However, if I use the same, exact piles of paint on paper...no lifting, no overly glossy appearance and no streaking. WTF??? ![]() The only thing I can think of (after 2 days of messing around and wanting to gouge out my own eyes in frustration) is the high humidity here in central Florida. According to the Weather Channel app on my phone, it is currently 79% and was higher, like 83%, a few hours ago. Could I have seriously botched my panels? I didn't add anything strange or uncalled for in the instructions. I am just really baffled. Help!! |
#2
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It sounds as if it is an absorbancy issue. I'm not familiar with Koo's recipe, so I can't address that. But RSG may have different strengths depending on the source, so in my experience, there is a certain amount of variability in recipes.
Do the panels feel hard or soft? If I have a panel sitting for a long time, I will very lightly sand it, though mainly to clean the surface. That might work. __________________ Bron http://frame-notes.blogspot.com/ http://bronislausjanulis.com/Site/Home.html |
#3
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I don't know how to answer the "hard or soft" question, Bron, because I've never really painted on panels before. They don't feel soft, certainly. They do feel very smooth and slick. And they are very, very shiny. I will definitely try sanding them again.
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#4
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Uh oh, Vermillion! I guess I better respond to this one.
Unfortunately, I don't know what to say. I've used that recipe for over 15 years, have taught it to hundreds of students, shared it with many other ET painters, and never (as in never) have had the problem you described. I agree with Bron that glues can vary in strength, but the ratio of glue/water/whiting in my recipe does not produce an especially hard gesso (not too hard, nor too soft, but somewhere in between) - so even if you did start out with a hard glue I don't think it could have tipped the panel into non-absorbent territory. As for the humidity, it might slow things down a bit, but shouldn't make things unworkable. A few questions: What rabbit skin glue did you use - from what supplier? What did you use for whiting? Have you tried rubbing the surface with denatured alcohol before beginning work? How thickly are you applying the paint? Is each layer dry to the touch before you apply the next? Its hard to say what's wrong without seeing and working on the panel. If you wish to send me a sample (to give me a chance to perhaps figure out what's wrong - or torture me, extract your revenge - whichever) I'd be happy to try and make it behave...or not! Koo |
#5
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Shiney is not good. Sounds like too much glue. I sometimes get a little sparkle if I'm trying for a harder gesso, but not shiney.
Bron |
#6
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Bron is right - very shiny isn't good. It should appear more like an unpainted piece of sheetrock (albeit a very smooth one, once you've sanded it). A harder gesso recipe (one with more glue in it) may give you a wee bit of shine, but still there shouldn't be too much (if you want a workable surface). Does it get more and more shiny the more you sand it? This would affirm Bron's idea that there's too much glue in the mix.
(Another indication of too much glue would be fine cracking - but this may not show up right away, only after you've wetted and worked the surface for a while.) I use a ratio of 1 part glue to 16 parts water - pretty standard, and not one that makes for super hard gesso. In my experience you can go down to about a 1:12 (maybe, just maybe, even a 1:11 ratio) and still make a workable gesso - but any more glue in the mix and it gets too hard. Perhaps the glue you used is a really strong one (although I've never run into a glue so strong that at a 1:16 ratio it made gesso too hard). How did you measure the glue - by volume or weight? Any chance that you altered the 1:16 ratio?? Sorry, don't mean to be presumptive, just trying to understand what happened... Koo Last edited by Koo Schadler; 15-05-12 at 12:56 PM. |
#7
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Oh, Koo! I didn't mean to disparage your recipe. I just said that so you all would know I used an actual gesso recipe and not one I pulled out of a hat. No revenge necessary. Although, if I ever get to one of your workshops, I may bring it along so you can have an example of how not to do it to show the class!!
On to the questions: RSG is Gamblin RSG from Dick Blick Whiting is Fredrix Powdered Marble Dust, again, from Dick Blick I have not rubbed the surface with denatured alcohol. I thin the paint way, way down. At least a dropper-full of RODI water. Usually more. I like to sneak up on the color. The paint is dry before I add the next layer. In fact, I can watch it dry as I lay the paint. I also buff it a bit with some cheesecloth every once in a while. Oh, and I used approximately 1 cup of water to 1 tablespoon of RSG and I measured both the RSG and the whiting by weight using our postage scale that is accurate to a tenth of an ounce. There aren't any fine cracks, or pin holes, but I do have a few big ones. I think they were caused by me not paying attention to where I placed the drying panels in relation to the AC ducts in my kitchen. I haven't sanded it yet this morning (I need to go buy some sand paper) but I will try that and see if the surface gets more shiny. I'll also take a look at some sheet rock whilst at Lowe's and see how that looks. It's so hard to make things when you have never seen the finished product. It's like we should have a "newbie-kit" - tiny, properly gessoed panel, small sample of properly tempered paint on said panel - so we can see it and pass it on to the next neophyte in the queue. Sorry, just my crazy ET fantasy! Heck, who am I kidding. I'd pay $$$ for that. Thanks for all the advice. I'll sand and update accordingly. |
#8
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Hello Vermillion,
I don't feel you were disparaging - I'm just disappointed, after all your efforts, that you didn't get the reward of a beautiful and receptive panel. It seems you did everything correctly. I'm puzzled... Koo |
#9
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Ah, well, puzzled is where I live these days. I've been looking through the notes I took when I made the panel and nothing is jumping out at me and sanding does not seem to be altering the surface in a positive way. Perhaps I just got a strangely strong batch of RSG? I suppose anything is possible.
It's not the first time something I have made has turned out oddly. Thanks for all the feedback. I'm sure it'll be better next time... |
#10
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you could always use it for oil paint
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