That's funny, try spraying it with pure alcohol, if my pigments wouldn't break down with water that's what I used. Of the pigments that I saved in alcohol, burnt umber gave me the most problems, after a few years the metal tops disintegrated. Put a plastic over the bottle before you screw on the top or your screwed.

Hi Elpa,
You hit it on the head, sandraca is an alcohol based varnish and was the varnish used.
I have a circa 1400 egg distempra painting that I had cleaned by the the best, in San Francisco's DeYoung Musium, I wouldn't varnish it at all. I got mine in the grand bazaar, Istambul in 1963.

Here is an egg tempra and mastic painting I did last year.
EGG-TEMPERA

TEMPERA'S ARE EMULSIONS, water and oil plus the stabilizer. The first tempera was made about 1000 A/D, first with mastic, than linseed oil. The ratio's went like this; one part egg, one part mastic or oil, OR, two parts egg, one part oil, one part mastic. More egg made it water based, more oil made it oil based. Later sun thickened oils or stand oil were used. Most liked to use Strasbourg turpentine [balsam], today we have to use Venetian or Canadian turpentine because no one imports Strasbourg to the U.S. except http://www.kremer-pigmente.de/

OIL OVER EGG TEMPERA

Van Eyck (1390-1441) became very skilled at this technique, painting in water based egg tempera, then glazing with oil and balsam, going back to tempera for details and glazing again, Giovanni Bellini (1430-1516), in his life time went from egg tempera to oil.

I'm going to start with egg yolk and alum.
11:30 12-03-04
Three transparent dry pigments. PY153 transparent yellow, PR122 transparent magenta and PB15.3 transparent cyan.
Black bananas, rare because they look so ugly. Most bananas are yellow, or red. These bananas are ready when the green turns to yellow which is after the brown is dark. The little apples taste just like the normal apples that is 5 times their volume.
1:2 alum sets quickly as water dries and won't move.
Sight with one eye and paint with two.
A white ground is important.
An absorbent white ground like chalk would be better then my acrylic panel, Wet sand the acrylic panel, I did it with a kitchen scrubbie.
Highlights can be scrubbed up while your painting as ground white.
Painting with egg is tedious and hard work. No wonder Botticelli championed oil.
Colors and edges have to be blended quickly as in fresco.
1:24 photo dark bkg.
Layers build up slowly.
More alum for a thicker coat, I've added ammonia also because it thickens the egg.
Woops, adding ammonia lifts lower levels. Like Venetian oil or mastic or copal or w/c on acrylic gesso.

2:04. Ammonia lifts the egg like an ereasure, and won't harm the egg. It's a gas in water and it evaporates. I've been delicating ereasing layers with the egg and ammonia mix I made.

3:24, that's it for today, the light has changed too much even though the subjects in the shade.

Here is the link showing the steps and tips for this painting.
http://www.realcolorwheel.com/eggtempera.htm

"these are my current pigments
Ultramarine violet reddish Lt.
Titanium dioxide buff off white."

I think you need a pure white more than off white.

"Ultramarine dk. blue.
French yellow- clear yellow."

  Is that clear like in clear yellow water or clear as opaque but minus a green or red side?
  If you could learn to use a transparent yellow with a transparent magenta and cyan you would have no trouble painting a whole natural looking scene.
  My transparent triad:
  Transparent Indian Yellow (warm yellow-brown, transparent nickel complex) PY153 from Zecchi.
  Transparent Quinacridone Red (neutral magenta) PR122 from Sennelier.
  Transparent Phthalocyanine Blue (neutral cyan) PB15.3 from Senopia.
  Opaque and secondary colors are used for added pazazz.

"Bohemian green earth."

  Are you doing portraits? Transparent brown and blue greens were used as under tones for warmer flesh color washes. Naples yellow and Venitian red were also used in this set.

'Raw umber from Cyprus.'

 It's the best.

'Terre ercoland - mixed orange earths.'

  You need a translucent Burnt Sienna and Raw Sienna, an opaque yellow oxide, an opaque warm red oxide and a burnt umber.

'Raw sienna yellow fr, Italy.
I have about $100.00 to spend and would like to end up with a palette to which I would not have to add to for a while. In other words a good beginning palette.'

Both opaque viridian and thalo green paint well, viridian dissolves into paint easier. Thalo green I store wet in some water and a little gum arabic, That keeps it from clumping.
I like a pale yellow -green so I mix a dry batch of Bismuth yellow and viridian.

A warmer cad yellow medium yellow and cad orange and red PR88 Thioindigoid Red should take the place of cad red which doesn't suspend as well. That round out the palette so you can paint anything with out black pigment. you would be doing without a dioxine purple, but you can mix the color.

Hi Paul,
I took this from my color course..

Egg yolk contains albumen [water], egg oil [nondrying] and lecithin [emulsifier]. Egg yolk itself is a painting medium, it bleaches white in sunlight. Mix egg yolk and water 1:1 to dry pigment, 1:1:1 is good. Egg, unvarnished looks like gouache, it's a flat finish. Egg and egg emulsions dry hard, elastic and more resistant than oil color mediums by themselves. Oil of cloves, one drop per egg, will preserve a jar sealed wet egg, kept cool for one year. The icon, painted on wood was the next medium after fresco. In Byzantium, after a ninth-century council had confirmed the defeat of the Iconoclasts and made it safe to paint in the less durable egg, the style spread over Northern Europe and stayed in Russia for eight centuries.

Egg without the addition of oil is called distemper, this was a preferred style from Giotto [1266-1337] to Botticelli [1444-1510], The addition of alum to the egg made it waterproof. Giotto also added cherry gum to make it more fluid, acting as a preservative as it was slightly alkaline. The support was wood or linen primed with gypsum or chalk. The ground had to be kept very clean because the thin medium shows through colors. A poor ground could be improved by a coat of egg and neutral lime white before painting. Sandarac (sandracca) was a good hard, final varnish. Today, damar will do the job.

When egg white is used, it's called glair medium and was used like ink on illuminated manuscripts in the 5th century, and as a size for gold leaf. Egg white and alum make a good bodied paint medium, capable of making very opaque strokes.

EGG-TEMPERA

TEMPERA'S ARE EMULSIONS, water and oil plus the stabilizer. The first tempera was made about 1000 A/D, first with mastic, then linseed oil. The ratio's went like this; one part egg, one part mastic or oil, OR, two parts egg, one part oil, one part mastic. More egg made it water based, more oil made it oil based. Later sun thickened oils or stand oil were used. Most liked to use Strasbourg turpentine [balsam], today we have to use Venetian or Canadian turpentine because no one imports Strasbourg to the U.S. except http://www.kremer-pigmente.de/

I've been doing a lot of fresco lately, so I ended up testing every dry pigment I could get my hands on. That cost over 2 thousand. The testing took a year, today I'm finished.