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Old 22-03-09, 03:18 PM
StevenW StevenW is offline
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Hi,

I have been experimenting with Tempera for many months now to learn about them as they are new to me (in depth anyway) and apply them to natural stone, limestone and marble in particular.

The Parthenon was once painted and ancient Greeks and Egyptians used paint on their stone sculptures, presumably Tempera in many cases as it was one of the only paints available at that time.. I understand from my research that cedar and lindseed oils were used as a protectant to seal the paint, but my questions arise not from sealing, but rather binding.

Anyway, I am now starting to investigate the use of different acids in the transport because my previous experiments were not satisfactory on two accounts: Either the Tempera was too muddy or too thin using water and egg alone as the vehicle.. I had either too much pigment or too much water and although the stone took it in either case, I am by no means convinced that my attempts have been as good or as elegant as original work by the ancients.

So then, I am now going to try using lemon juice and or lime juice as an acid for the base, which will hopefully act as a penetrant to "bake" the pigment into the stone as opposed to simply laying it on the surface or using many, many thin coats.

I wouldn't expect to find people doing what I am trying to do, I only know of a few who paint/wash/polychrome stone to begin with, but they are using modern techniques and they know about stone and sculpture, but not about et so much.

Have any of you used any acids in et and do you have ay insight as to what I can expect? Are there any long-term effects that I should be aware of by using an acid in the transport?

Thanks in advance,

StevenW

Oh, P.S. I have several pieces now that have been patiently waiting the minimum 6 months (as I understand) for the tempera to rest before buffing and or sealing and I will try one piece today with a gentle cloth and a few drops of cedar oil and do a hand rub over the surface. I have tried before (too early probably) and got a muddy texture where I was looking for sheen. I have also encountered the same or similar by doing a dry rub. Any thoughts on this are also welcome..

Sincerely,

Steven

Last edited by StevenW; 22-03-09 at 03:31 PM.
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Old 23-03-09, 03:18 AM
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Koo Schadler Koo Schadler is offline
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Hello Steven,

While waiting 6 months to buff an et is ideal (it gives time for the paint to polymerize), its certainly not requisite. In fact, I start gently polishing my paintings within the first hour or two of working on them - I polish as I go along to smooth the surface, check my tempering, and just to make it look nice. So for your colors to be muddying after 6 months doesn't make sense. Possible reasons it may do this is (1) too little egg - your colors are under bound, and thus lifting, (2) too much egg - your surface is greasy, (3) perhaps you aren't blending your pigment and egg well enough when you first make your paints, and when you polish you are loosening undistributed clumps of pigment particles, (4) you are buffing too aggressively (although after 6 months the surface should be fairly durable - nonetheless use a very soft cloth and be attentive and gentle in your polishing), or finally (5) the cedar oil is acting as a solvent. Number 5 makes the most sense to me. I haven't heard of using cedar oil as a finish on tempera; where did you learn that? Is cedar oil a drying oil? If you have tempered your paints properly you don't need to buff with oil; the polymerized egg oil when buffed is sufficient to bring out a nice subtle shine. I'd like to hear more about cedar oil...

I'm interested in your stone painting effort, which is all new to me. My understanding is that egg yolk is in no way a strong enough binder for a stone surface. When they used it in the Renaissance atop dry fresco (for example, for colors that would otherwise react to the lime in wet fresco, such as lapis, or as touch up paint) it generally peeled off fairly soon (I have a book that quotes a letter from Benozzo Gozzoli to his Medici patron discussing this concern while he worked on his gem of a chapel in Florence). Hence all the Madonnas missing their lapis lazuli robes in fresco paintings. My understanding is that while drying oils weren't highly refined until the 1300s or something like that, they'd been in use as a binder in a cruder form for centuries beforehand. Perhaps the Greeks were using some percentage of oil to strengthen the egg yolk binder? I don't know, but I'm curious, so hopefully someone out there does. The one precaution I can think of regarding acid as a transport is the above mentioned reaction of ultramarine blue to it.
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Old 23-03-09, 04:56 PM
StevenW StevenW is offline
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Quote:
Originally Posted by Koo Schadler View Post
Hello Steven,

While waiting 6 months to buff an et is ideal (it gives time for the paint to polymerize), its certainly not requisite. In fact, I start gently polishing my paintings within the first hour or two of working on them -

This is the kind of information I have been looking for, thank you.. I did indeed start buffing, or more accurately rubbing the paints as they dried and this caused the muddiness I think.


I polish as I go along to smooth the surface, check my tempering, and just to make it look nice. So for your colors to be muddying after 6 months doesn't make sense.

I misspoke maybe, I just tried buffing one out yesterday after having finally waited 6-months and it worked fabulously. I only discovered tempera last year in my research on a Horus sculpture that I had been carving and other than a vague notion as an old egg-based paint I really didn't know much if anything else about it. I've been doing my homework though and read all the primers here as well as a great deal of study on google books etc..



Possible reasons it may do this is (1) too little egg - your colors are under bound, and thus lifting, (2) too much egg - your surface is greasy, (3) perhaps you aren't blending your pigment and egg well enough when you first make your paints, and when you polish you are loosening undistributed clumps of pigment particles, (4) you are buffing too aggressively (although after 6 months the surface should be fairly durable - nonetheless use a very soft cloth and be attentive and gentle in your polishing), or finally (5) the cedar oil is acting as a solvent. Number 5 makes the most sense to me. I haven't heard of using cedar oil as a finish on tempera; where did you learn that?

I do not remember which article or book specifically, but it was mentioned that the Egyptians used cedar oil as a protectant over furniture, much of it painted furniture and so I think I probably made the assumption it was tempera, which at the time made sense to me. I had also known that Greek and Egyptian sculptors would treat marble with olive oil, linseed oil and or cedar oil to seal, protect, bring out translucence in the rock and also as a lubricant for sanding and fine polishing as they did not have Home Depot and mechanical sanders and fine grit sand paper back then and so forth. :)

Is cedar oil a drying oil? If you have tempered your paints properly you don't need to buff with oil; the polymerized egg oil when buffed is sufficient to bring out a nice subtle shine. I'd like to hear more about cedar oil...

Well I don't know if it is a drying oil, but it is a good question, I simply assumed they all dried after a long enough period of time.. All I know is that I am trying every possible combination of methods that I can imagine as being pragmatic in those days. This is almost as much a history lesson as an art experience and I have become wrapped up in it.

I'm interested in your stone painting effort, which is all new to me. My understanding is that egg yolk is in no way a strong enough binder for a stone surface.

Correct, by itself it is probably not and most sculpture in those days as well as frescoes on walls and so forth had a plaster/gypsum substrate in order to take the paint, but this was not always so, they were highly experimental people and there are examples of smaller sculptures with paint applied directly to the stone as well as friezes in limestone and whatnot. What I gather is that they never "perfected" a method of painting stone to withstand outdoor environments, which is understandable, but much of the smaller sculpture in tombs for instance had no substrate and still holds pigment after thousands of years.


When they used it in the Renaissance atop dry fresco (for example, for colors that would otherwise react to the lime in wet fresco, such as lapis, or as touch up paint) it generally peeled off fairly soon (I have a book that quotes a letter from Benozzo Gozzoli to his Medici patron discussing this concern while he worked on his gem of a chapel in Florence). Hence all the Madonnas missing their lapis lazuli robes in fresco paintings. My understanding is that while drying oils weren't highly refined until the 1300s or something like that, they'd been in use as a binder in a cruder form for centuries beforehand. Perhaps the Greeks were using some percentage of oil to strengthen the egg yolk binder?

Yes, or preparing the surface with oils in order to "loosen up" the crystalline structure of the marble so that it would soak up pigment after a time. The friezes of the Parthenon were once brightly colored and Phidias must have at some point considered different approaches to painting them. I am not sure if they had substrate or not, perhaps so, but these are the kinds of questions I am here to find out and pick your brains on. I do not think it is fair to simply assume they found no good way to paint rock and therefore used substrate on every wall and sculpture. I think they were smarter than this.. Someone at some point must have known that a wine stain for instance, spilled on a marble table was almost impossible to remove and this is how I put two and two together with tempera using a weak acid transport.

I don't know, but I'm curious, so hopefully someone out there does. The one precaution I can think of regarding acid as a transport is the above mentioned reaction of ultramarine blue to it.
Sure, I have many marble and limestone tiles painted at different stages and using different mixtures and applications in order to find one that I like and one that seems genuine and this includes some with Lapis Lazuli ground as pigment. If there is one nice thing about bombing the mountains in Afghanistan it is that Lapis is falling out of the hills all over the place after it rains and the price per pound has come down considerably. Go figure...

Anyway, thank you for your time and I will see if I can get a pic up of my little Horus project, I have other questions and observations that can perhaps be addressed here as well.


Thanks again,

Steven
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Old 24-03-09, 01:18 PM
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Dennis H Dennis H is offline
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Have you tried painting with a little quicklime, as is used in fresco? Maybe that would work for you on stone, although you would be starting from a white vehicle rather than a colorless one. You'd have to slake it first, which can be a little exciting, or buy aged lime putty from someone like Kremer. Some "milk paints" as are used on furniture are composed of lime and casein. You can buy a wide range of ready mixed colors in binder from certain furniture-making supply/tool stores. Just an idea. I have no idea if it would work for you, however...
D
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Old 24-03-09, 01:25 PM
dbclemons dbclemons is offline
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What will activate the binding strength is a base, not an acid. Alkali such as slacked lime is often used for masonry paints, as with casein. I don't have any info on egg tempera and lime. It can be used with wet plaster, such as buon fresco. There are several pigments that are not alkali resistant, or acid resistant.

Cedar oil can darken considerably as it ages. I wouldn't recommend applying it on top of paint, or using any oil on paint, for that matter.

Are you painting on bare stone or preparing it somehow beforehand?
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Old 24-03-09, 03:13 PM
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Koo Schadler Koo Schadler is offline
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Hello Steven

I want to return to the topic of polishing for a bit. To be clear, if your surface is dry, and your tempering correct (not over or under), you should be able to polish immediately. It has to be very gentle - you are not trying to abrade the surface. My hand barely applies pressure, but little by little the shine begins to appear. With enough polishing you can actually bring out a shine akin to fine porcelain within the first few days of working on an et painting. It is lovely, but its not a good idea, as the surface becomes too slick and closed and not receptive to subsequent layers of paint.

Oils can be either drying or non drying. For example, linseed and walnut and poppy, when exposed to air, oxidize and polymerize and eventually form a dry paint film that can never go back to what it once was. On the other hand you could leave olive oil on your kitchen counter for years and it will merely become a tacky, gummy mess. So not every oil can be made into paint. I have never seen cedar oil referenced as a drying oil, but I don't know for sure. Also, be wary of anything used on furniture being then applied to fine art; in furniture yellowing is generally not a consideration.

(As an aside, my understanding is that the egg oil within the yolk is actually a non-drying oil, but when combined with the powerfully drying albumen in the yolk [which is actually too strong a dryer - on its own it can be brittle], [unless used in thin layers as glair, another topic, the tangents are multiplying...] ANYHOW, the non drying egg oil and the powerfully drying albumen combine and contribute their properties to each other to form a good paint film. At least that is my understanding.)

In my early et days before I knew how to make gesso I applied et directly to plaster. After all, it looked like a gesso surface, and is very absorbent. But the paint flaked off within a few months. The rabbit skin glue, and the degree to which it is "activated" every time a stroke of wet paint is applied, combined with the absorbency of true gesso, seem to be the winning combination. I mention this because I'm not clear how, even if you apply a substrate of plaster to stone, the et will stick without the glue there to do its part?

A great discussion for a tempera nerd (meaning myself), Steven. Thanks for initiating it.
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Old 25-03-09, 03:00 AM
StevenW StevenW is offline
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Gentlemen,

Thank you so much for your thoughtful and informative replies. I read them all twice to make sure I did not miss anything. Tonight I chose to do a light buffing as Koo had mentioned within 24 hours of application and I used a very soft and fine sandpaper (1500 wet/dry) that is used on BMW's and Mercedes Benz paint finishes and I am thrilled. While I did not achieve a "porcelain" finish, it was not necessarily my intent. I just wanted a little sheen and I got it.. My first few tries resulted in a finish that looked like dried egg on a car in the summer heat that was pummeled by a dozen high school students (little monsters). :)

I think my first few batches of tempera were not so well made either. This time instead of throwing the whole yolk in, I pierced the sack (as is mentioned in the primer here and is well written) and made sure none of the whites or albumen made it into the mix so I got a nice flowing paint. I also made sure I ground my Lapis Lazuli to a very fine dust and hit that with a few drops of acid to further disintegrate it and make a soft paste. The deep, deep blue I achieved was more than I could hope for and I am just hopeful that the end result will do the work justice.

Thanks again for your time and interest in helping me. I'll be around and poke my head in from time to time and perhaps pick your brains some more.

Sincerely,

Steven W
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Old 28-03-09, 04:52 PM
StevenW StevenW is offline
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Quote:
Originally Posted by dbclemons View Post
What will activate the binding strength is a base, not an acid. Alkali such as slacked lime is often used for masonry paints, as with casein. I don't have any info on egg tempera and lime. It can be used with wet plaster, such as buon fresco. There are several pigments that are not alkali resistant, or acid resistant.

Cedar oil can darken considerably as it ages. I wouldn't recommend applying it on top of paint, or using any oil on paint, for that matter.

Are you painting on bare stone or preparing it somehow beforehand?

I am also glad I did not miss this, thank you.. I was trying to paint on "naked" stone because I did not want to create the impression of having concealed the stone in gesso/bole or that it was an unknown or indeterminate material beneath. In short I wished to have it appear deliberate and with the natural marble and veining showing and leveraging the translucent properties of tempera, but it appears that I may need to gesso the stone and then use a bole for gilding etc,.. That is unless I can develop another method. I had hoped the acid would act as a transport to deliver the pigment deep enough beneath the surface so that no other binder was necessary, but I dunno to be honest. I haven't had enough time to see whether the paint will even hold longer than a year or so.. I know this much, the rock itself doesn't particularly like gilding/gold leaf unless it is taken to a very high polish and even then it can flake, so I think I'm going to go and hunt a few rabbits..
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