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mona 07-07-13 09:18 PM

Renaissance wax as a protective coating over egg tempera and gold leaf surfaces?
I am looking into the following product myself and will report back on my try with this, but has anyone so far tried Renaissance wax, an acid-free microcrystalline unique wax as a varnish substitute or protective coating which apparently has been used by several reputable museums out there, both in Britain and the U.S., at least according to this link which may be advertisement- based?

If so, have you tried it over either oil gilding, or over egg tempera as an isolating layer to paint in oil on top of, or as a final varnish? I am exploring the use of this product due to how I am currently working on a gilded panel that has 24 karat gold leaf painted over in oils, and yet I am also wanting to see if it isolates egg tempera well for a finish with oils. I read in one place that it may be less darkening over time than a shellac-based isolation layer, and yet I know we have established through Koo's research the validity of this method over egg tempera, even though Koo continues to look for alternative methods herself as do I.

Here is a link on this product which is being touted for use over gold leaf, tempera, marble, wood, and other interesting metal and non-metal surfaces: A perhaps non-neutral Wikipedia report on this wax states the cautions about its use in conservation which include polyethylene content (which makes it hard to remove), and yet perhaps that is a non-issue in a combined painting method or final varnish method (?)

thanks and regards to all, Mona

Koo Schadler 29-07-13 01:40 PM

Hi Mona,

I've tried several different wax mediums, including Renaissance (as well as Gamblin and Dorland wax mediums). They all work well over tempera; in fact, of the many different sorts of varnishes I've tried, I would say the wax mediums are most in keeping with tempera's "nature", so to speak. What I mean by that is that wax mediums don't greatly saturate and deepen the dark values of a tempera painting (unlike some other varnishes, which can really darken the darks...although I actually liking my darks more saturated) and the shine imparted by wax is soft and not overly shiny – it is more akin to the "egg shell shine" that naturally occurs on an unvarnished tempera painting.

From what I understand, all the commercial wax mediums (whether the wax is derived from petroleum, as in the Renaissance formulation; or from bees, as with the other two) also contain some percentage of resin and mineral spirits. In short, they should be used with good ventilation.

If you apply a wax medium too soon to a completed tempera, you may lift up color. Michael Bergt recommends first finishing off a tempera painting with a layer of egg yolk medium thinned with water (what is technically known as a nourishing layer), and then letting the painting cure for something like 6-8 weeks before applying the wax. Banjie Nicolas recommends waiting even longer for a painting to cure - I think she waits about 3 months, to be on the safe side. Not sure of those exact wait periods, but suffice to say that you shouldn't wax your tempera right away - give it some time to polymerize.

Michael and Banjie are both experts at applying a wax medium - they get gorgeous surfaces. I've found that it takes some practice to apply it consistently (I'm still learning to do it as well as they do...). I use a lint-free, blue shop rag to apply the wax in a gentle, circular motion, working carefully to get a consistent application. Then, if necessary, I smooth it out further with delicate strokes from a 1 1/2" wide, flat, soft-haired brush. If you make a mistake, and the wax starts to set up a bit before you have the look you want, it can be adjusted and/or removed with OMS (odorless mineral spirits). Once you are happy with your application, let the painting sit overnight (perhaps a bit longer if you've applied a thicker layer of wax). Polish the surface once its hard and dry, to pull out a really lovely finish.

Regarding shellac as a finish: to be clear, there are people who object strongly to its use as a varnish on egg tempera. Some of the objection is aesthetic – shellac saturates the darks, and is shinier than a traditional tempera surface. However aesthetics are a personal decision and if a person likes the effects of shellac, well, its okay to like those effects.

However other objections to shellac are technical: shellac is brittle as it ages, and it can be yellowing. I’ve talked to many people, including conservators, art manufacturers and woodworkers about these issues, and feel they have been addressed. If applied thinly and to a solid panel, the brittleness is addressed (tempera paint also gets brittle as it ages, which is one of the reasons we work on solid panels). Regarding yellowing, its possible to buy "platina", very pale varieties of shellac that, if applied in a thin layer, impart no discoloration. From what I’ve read shellac’s color is stable: its doesn’t continue to get more yellow as it ages, but rather stays whatever color it was when first applied - and I have a 15 year old test strip of shellac that so far bears this out; there is not one bit of discoloration. In addition to working with a "platina" shellac, it is also important to use the "dewaxed" varieties.

Despite what I've just said, you can find people who vehemently disagree to shellac being applied to tempera - just as many people strongly feel that no varnish of any sort should be put on a tempera painting, even though many traditional tempera techniques employ varnishes. As mentioned, I think, if technical considerations are addressed, varnishing is a perfectly acceptable option.

Hope that helps, Mona. I'd love to hear how it works for you. Happy tempering - hope you are staying cool...


Salamander 29-07-13 02:12 PM

Always good to hear your input Koo, thanks

dbclemons 01-08-13 04:06 AM


Originally Posted by Koo Schadler (Post 6664) well as Gamblin and Dorland wax mediums)...whether the wax is derived from petroleum, as in the Renaissance formulation; or from bees, as with the other two) ...

I'm pretty sure that Dorland's Wax medium is a mixture of several waxes including ozkerite and micro-crystalline.

To mona:

If so, have you tried it over either oil gilding, or over egg tempera as an isolating layer to paint in oil on top of...
I would avoid painting oil over wax. It's not a firm or stable enough surface for oil to be happy on top of it. If you're wanting to create a barrier between the tempera and the oil paint, I'd go with either 2# de-waxed clear shellac, or a thin resin varnish, like a retouch. You might see a color shift in the tempera when you add either of these.

mona 01-08-13 10:50 PM

Renaissance wax as a protective coating over egg tempera and gold leaf surfaces?
Dear Koo, Eric, DB, and all, I have not yet had the opportunity to test out the Renaissance wax I have purchased on either of the surfaces I was asking about, and yet I am grateful to Koo for warning me about the waiting period over egg tempera.

The actual project I have at hand is an oil painting over gold leaf on a panel that I have oil-gilded, and my decision at the moment I think will be to use the shellac varnish that Michael Bergt recommended to me, and yet he is recommending a 3-part shellac crystals to one part denatured alcohol, whereas I am wondering if I can get away with a 5 to 1 or even 6 to 1 ratio on that one. So has anyone tried the shellac varnish over the gold leaf?, and yet I know that Michael has produced a whole volume of gold-leafed panels which he has incised and these can be seen on his website. I had asked Michael about the Renaissance wax too, and yet he has been busy fielding his latest show, so I expect eventually to test that out myself when I have got less time pressure. Several surgeries this year have thrown my entire line-up off not either, but almost, and yet I am glad to be back among the useful painters out there.

Koo, thanks for patiently reviewing the shellac method again for us all, and yes, platina would be the way to go on the shellac too, as it is the blondest crystal out there as far as I have been able to determine also. DB thanks also for weighing in with your perspective on using oil over wax, since I will actually be painting over the varnished surface of the outer border on this gilded panel, and here is a link to the work I have been discussing with my question, one which is still in progress, and which will have a background of a garden and a wisteria vine, if I can pull that part off, on the outer section of the panel with portions of the gilding still visible:


best to all! Mona

Koo Schadler 02-08-13 07:32 PM

Hi Mona,

Sorry to hear about your health challenges )-: Hope you are all set with surgeries for a while and are back to the easel.

I've tried shellac over gold leaf a couple of times and it worked well (in my limited experience). I believe it is better to use less shellac than more...less yellowing, less brittleness, etc. I've had luck varnishing with a 1 part shellac to 6 parts denatured alcohol. I've also tried ratios of 1:8, even 1:12 - they can work okay as isolating layers, but tend to be insufficient coverage as a varnish. You want enough shellac to get a consistent finish on the surface, so if your ground is especially absorbent, you might need a richer all depends on your surface.

In short, its best to practice before you apply it to a treasured piece of art, to make sure you have the right ratio to achieve your goals (i.e. either to isolate paint layers, in which case you need a lesser percentage of shellac; or to varnish a surface, in which case you might need a higher percentage of shellac). As you know, it sets up quickly and shouldn't be reworked. I know you already know all this, but I want to be clear with anyone reading this for whom shellac varnishing is new - please practice first!


mona 03-08-13 06:01 PM

Renaissance was as a protective coating over egg tempera and gold leaf surfaces
Thanks for the good wishes Koo, and for your thoughts on the shellac. Caution is always advisable whenever possible, yes. :-)

happy painting, Mona

PhilS 07-08-13 04:56 PM

Hello all,

An argument against varnishing, waxing, etc.:
A couple of years back I repaired a painting I had given my parents 15 years ago (slight mold growth). It was a painting with an uneven sheen—some parts matte, some shiny—but I found that buffing with cotton balls brought the entire surface to a beautiful, overall semi-gloss. After 15 years, the surface had hardened to the point where it couldn't possibly be scratched with a fingernail. Point being: egg tempera will eventually "varnish itself" over time so why apply a surface layer that might yellow or degrade?

It takes a couple of years for ET to become scratch-proof but I've found that it can safely be buffed to an even sheen after a couple of months.


Koo Schadler 09-08-13 01:50 PM

Hi Phil,

Apologies for my sounding like a broken record, but I must, once again, defend the option of varnishing an egg tempera.

Before doing so, I'll enthusiastically agree with you that polishing a well-tempered, cured (polymerized) egg tempera painting creates a gorgeous surface that is unlike any other. I totally understand its appeal. Every tempera artist should try it at least once (if not more...)

But that doesn't mean it should be the one and only option. There are sound reasons to choose varnishing....

1. Saturation. Depending on the type used, a varnish will deepen, more or less (I prefer more), the darks on a tempera painting and expand its value range. Aesthetically speaking, I love an expanded value range.

2. Protection. Three weeks ago I had a painting due for a show, brought it to my photographer, and (to her horror) she inadvertently put a big scratch right in the middle of the painting. (It was one of the pieces in the Cape show that you and I have work in...argh, I wanted to cry!) It was an unvarnished, fresh tempera painting - they are sooo vulnerable to scratching. I fixed it but it was an arduous repair. Some artists choose to frame new temperas under glass to protect them, but this really impacts how the work looks and can lead to mold. A varnish on the other hand, depending on what sort is used, can protect a tempera against water, mold, and scratches.

3. Shine. For those who so deeply love the soft, egg-shell shine of an unvarnished tempera, I know this can be hard to believe! But, in fact, there are other beautiful surfaces to chose from; i.e. a somewhat more shiny, enameled, jewel-like finish (akin to a Van Eyck). Each to his aesthetic own.

I realize that polishing a cured tempera will also deepen the values - but only minimally, not as dramatically as would certain varnishes, and certainly not as quickly. Polymerization and polishing also harden the surface but, again, you have to wait a year or two. I don't know any professional painter who can wait that long before putting their work out in the world; it just not practical. I know this sounds crass - that time factors into one's artistic choices - but its an undeniable fact that anyone who is painting for a living contends with deadlines (or they don't make a living as a painter).

Its also important to note that not all varnishes yellow or get brittle. If a tempera artist wanted saturation and protection but not yellowing or brittleness, they could pick an appropriate varnish to achieve those goals. To whatever degree some varnishes do yellow or get brittle, the artist can take that into consideration (i.e. some artists actually don't mind a slight, unifying yellow tone on an image; or, use a final [not retouch] varnish that can be removed and reapplied at a later date, as oil painters do. Regarding brittleness, a small percentage won't necessary damage a painting that's on a well-made, solid panel support - never mind that tempera itself gets brittle as it ages, and yet that doesn't stop us from painting with it!).

In short, every material, medium and working method has benefits and drawbacks. If drawbacks kept us from working with a particular support, ground, medium, or finish we wouldn't have anything left to work with - they all have pros and cons. It seems, if we understand (to the extent possible) the choices out there, and the consequences (good and bad) to those choices, an artist should be free to work in a variety of ways, especially if it helps a painter achieve his or her artistic goals.

So, yet again I will say, that if a tempera artist likes the saturation, protection and shine of a varnish, and has considered and accepted the consequences of that varnish - then go ahead and varnish. I don't think people often object to varnishing an oil painting, even though the benefits and drawbacks are generally the same as varnishing a tempera. The only difference is, by varnishing a tempera, you lose the unique, eggshell finish that occurs only on an egg tempera. But not all tempera artists work in the medium for that reason.

I rest my case. And welcome objections. Its always fun to probe the possibilities of tempera.

Sorry to have missed you at the opening on the Cape, Phil. Hope it went well - I have no doubt that your beautiful, unvarnished temperas were greatly admired...


PhilS 09-08-13 03:05 PM

Hi Koo,

Points well taken, as usual.

God knows I've had to repair a bunch of scratched paintings (or paintings licked by gallery owner's dogs). It would also be interesting to see how my paintings would look with a little more saturation in the dark areas. But I do like the simplicity of egg yolk, water, and pigment. And I like to tell my students that unvarnished egg tempera paintings done 500 years ago are, for the most part, better preserved than oil paintings done at the same time.

OK, truth be told, I'm too lazy to try to figure out varnishing or waxing.

Missed you at the show opening. I heard a lot of ooos and ahhhs coming from the alcove where your paintings were. They just shook their heads at mine. Especially the one of the gas can spout pointing at a duck.



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