Buon Fresco Painting #37, pg7

September 9th, 2004
Nice color. Snow peas, quomquats, a hybrid plum and peach called Dinosaur Egg and red tamarillos from New Zealand.
The intonaco was made of 1.5 lime, 1 small grit sand #30, .5 marble dust.
6:45, Layout in Indian yellow.
7:15, 100% coverage done with the #9 Series 7 W/N sable. I started with this set of transparent primaries, Williamsburg Quinacridone Magenta, PR122, PB15.3 Sinopia's true Phthalocyanine cyan and Zecchi's Nickel Complex PY153 Indian yellow. Plus titanium white. This triad should make the greatest verity of neutral darks.

Just a note, Sinopia's Indian yellow is labeled PG10 F = Green Gold, it could be called Indian Yellow G/s but it's not. Williamsburg Magenta does not match the perfect color of Liquitex's Acra Violet, it's name was changed to Liquitex Acra Magenta PR122.

Williamsburg Magenta has more like a Alizarin Crimson base with PR202 added, it's not a clean color, not the PR122 that Liquitex uses. I thought the ASTM was to eliminate confusion.

This is a quote from the Artist's Handbook of Materials and Techniques, 1940.
The following list of ASTM-approved pigments is arranged according to the color index name. This system of color index names has been developed to eliminate the confusion brought about by the excessive use of various color names for pigment identification.

Well we need a new system, this 1940 Color Index system doesn't work anymore. One reason is because it is based on Chevreul's red, yellow and blue colorwheel instead of the correct yellow, magenta, cyan colorwheel. Another reason is it does not show the position relationship between any two colors.

PV19 is quinacridone, the chemical can be a transparent color from red to magenta to violet.
Don't confuse Quinacridone Magenta PV19 with Quinacridone Magenta Y, PR122. PR122 is not only the right color but it's "The most lightfast organic colorant in this hue range."
Mayer's says the same thing about PV19 but I have a lime fresco test where it turns white.

Today I notice a lot of distributers using only the PV19 to cover the whole magenta range. Don't be mislead!
Sennelier's PR122 is called quinacridone red, go figure. It all goes back to calling magenta the primary red. Chevreul started it in 1839 and our government backs it with the ASTM and the State School Standards, teaching it in all our schools, red, yellow and blue are the primaries. Very sad..
Sennelier's PR122 is the only pure magenta.

7:30, I let it set for ten minutes then wet the whole fresco with lime water. I paint with the panel in an upright angle, wet it with spray in the horizontal position.
7:40, added thioindigoid red PR88 and cad yellow medium. We need a warm transparent yellow, the chemical is called Flavanthrone, an Anthraquinone Class pigment, PY112. This would be the best Indian yellow O/s. But no one has it yet.
7:45, added cad orange and viridian. Williamsburg Magenta PR122 is not the same as Liquitex PR122, it does not make a decent orange or red as it should have.
9:00 sprayed it down with limewater again. I'm real close to finished.
9:15, finished.

09-11-04, The Williamsburg Magenta PR122 is turning brown in the wet lime jar test and fresco already, this is not a PR122 trait. It is an alizarin crimson trait though.

Start 6:00 Am, brushed on lime water until it soaked in all over the fresco. This removed any building crust that will impede color absorption. The next day's crust can be removed with a light wet sponging.

Sinopia Priderit yellow PY157 RCW#36.0 is a yellow green that is made similar to cad yellow light and viridian mixed. This makes a warmer yellow-green than if you mix it with Thalo blue.
Yes, you could use Thalo green PG7. I store Thalo green in alcohol because it's so hard to break down in water each time I want it. It still has to be worked from getting dry on the palette. Viridian PG16 is easier to use and gives me the same colors including neutral dark.
This Color # for both pigments on the Real Color Wheel would be RCW#31.0.
That is Green, Arc #31 of 36 arcs in the circle. 10 degrees of analogous colors are available in each arc.

Daniel Smith's Magenta is PR212, is a transparent violet side magenta. It does not make good reds or oranges. That would be RCW#14.6 Transparent on the Real Color Wheel.
The point six is the transparent mass-tone of Magenta-violet/side. RCW#14.0 would be a tint of the transparent mass color.

Zecchi Thioindigoid red PR88. RCW#7.0 Opaque is better than the same colored pigment cadmium red. Both colors have similar opaque qualities. Thioindigoid red stays brighter on the fresco and has better painting qualities.

Cobalt blue light PB28. RCW#22.00 Opaque is the only cobalt blue I found permanent. The rest turned dark gray.

Cadmium orange PO20. RCW#4.0 Opaque Cadmium orange.

Sinopia phthalocyanine 15.3. RCW#25.6 Transparent is a clean cyan.

Viridian green PG18. RCW#31.0 is easy to use and works like phthalocyanine green, in fresco only.
Here is my set up.

8:50, 90% finished, sprayed it down completely.
9:20, sprayed again.
9:45, finished.

10:15, Sprayed again.

6:30, finished. I fixed the chip at the bottom later that day, soaked it good, mixed some fresh intonaco, matched the color and painted it. I can't even tell where it was.

Cadmium red would not have given me this brilliance in the Red Bottle. Thioindigoid red PR88 (same as Grumbacher Red) is the better choice in all media.
Two days later I decided to do some experimenting. Gloss the bottle with Cera Cola and make it shiny with bees wax, then add a glass painted in cera colla with pigment.

TIP: Add to a painting with ammonia, remove paint with water.
I also want to try repairing. I drew another glass on the left with pencil, it erases very easily off the fresco and nothing moves. It was washed this morning and all colors had absorbed beautifully. I want to cut out the new glasses outline and lay new intonaco, maybe even shape it in bas relief.

9-25-4. The glass is drawn in, the wine bottle got it's first coat of cera colla. In the morning I'll soak it and start chipping away at the glass area of the intonaco. The applied cera colla media looks milky tonight.
9-26-4. It still looked milky in the morning so I put some more on and laid it in the sun. Hmm.. It's still milky in areas, it's going to take more buffing heat. Instead I added some turpentine to the cera colla. This was a better answer, the wax stayed transparent.

I shot the picture, soaked the panel and started removing the intonaco for the glass. Lime hardens from the top and this one is already getting a hard crust that has a slight sheen. Under the crust the mortar is easy to remove. This picture is the buon fresco.

The next fresco page #38 shows the new giornate added and the Cera Colla work done to this fresco.