Painting on Location
by Donald A. Jusko

Fresco Pigment Tests, Blue Color Absorption
Layered Strokes

Buon Fresco, #28

Tile #9 broke. Large side, thin layer of large and small sand. Intonico, 3/16 inch thick, soaked 2 hours, skim milk on top.
7:15, 3-30-4, intonaco finished.

3-30-4, Testing Zecchi's Thalo blue, ultramarine blue, cobalt blue light, with titanium white and lime white. Combinations of each in 5 columns, each column has another pass of color. This is a test for lime fastness and absorption times.
4-8-4, RESULTS

09:20,09:29,11:01,11:50,12:40,Line 1, Thalo blue and limewater. 1 TO 2 COATS GOOD
0922,0932,1102,1151,1234,Line 2, Thalo blue + lime cream. 1 TO 5 COATS GOOD
0925,0934,1103,1152,1244,Line 3, Thalo blue + titanium white + lime cream. 1 TO 4 GOOD
0927,0936,1105,1153,1246,Line 4, Thalo blue + titanium white. 1 TO 2 GOOD
0948,1029,1109,1206,1248,Line 5, Thalo blue + Ult. Blue + limewater. ONLY THIN WORKED IN 1
0949,1030,1109,1207,1250,Line 6, Thalo blue + ult. blue + lime cream. 1 AND 5 GOOD
0950,1031,1110,1210,1253,Line 7, thalo blue + ult. blue + titanium white + lime cream. 1 GOOD
0952,1035,1111,1212,1254,Line 8, thalo blue + ult. blue + titanium white. 1 GOOD
1000,1036,1119,1217,1255,Line 9, Thalo blue + cobalt blue light + lime water. 1 GOOD
1002,1037,1121,1218,1256,Line 10, Thalo blue + cobalt blue light + lime cream. 1 TO 4 GOOD
1003,1038,1122,1220,1257,Line 11, Thalo blue + cobalt blue light + titanium white + lime cream. 1 GOOD
1005,1040,1124,1222,1258,Line 12, Thalo blue + cobalt blue light + titanium white. 0 WORKED
1007,1042,1125,1225,0102,Line 13, ultramarine blue + lime water. 1 GOOD
1008,1043,1126,1226,0104,Line 14, ultramarine blue + lime cream. 1 TO 5 GOOD
1010,1044,1128,1227,0107,Line 15, ultramarine blue + titanium white + lime cream. 1 GOOD
1011,1046,1129,1229,0108,Line 16, ultramarine blue + titanium white. 1 GOOD
1015,1048,1131,1230,0111,Line 17, cobalt blue light + lime water. fast pick-up, slow absorption. 1 GOOD
1017,1049,1132,1231,0112,Line 18, cobalt blue light + lime cream. 1 TO 5 GOOD
1020,1051,1133,1233,0112,Line 19, cobalt blue light + titanium white + lime cream. 1 TO 5 GOOD
1021,1053,1135,1235,0116,Line 20, cobalt blue light + titanium white. 1 GOOD

The bottom two rows.

Thalo blue 01:18 SPLOTCHY BECAUSE OF THE SMOOTH SURFACE. Ultramarine blue 01:21 GOOD. Cobalt blue light 0127 GOOD. Titanium white 0128 GOOD. Lime cream GOOD

Thalo blue + lime cream 01:19 GOOD. Ult. blue + lime cream 01-23 GOOD. Cobalt blue light + lime cream 01:27 GOOD. Titanium white + lime cream GOOD. Blank.
Six hours of painting time may have been too long.. I'm glad I have each boxed color's time.

04-08-04, It was too long a painting time. Thalo blue didn't absorb after the third layer of pigment. All of these blue colors are good when only one or two layers are used with lime water. All of the colors are good for 5 coats if lime cream is added to the color. Here is the results photo taken eight days later. Extra layers = Extra splotchy. I don't know why, maybe the pigment loads up too much.
09-05-04, I washed and scrubbed the tile. It cleaned up nicely.

One thing is really boggling up my mind.
It's Zecchi's and Sinopia's ultramarine blues.
On 1-20-4, In a lime jar test for Zecchi's ultramarine blue it turned white . In this 3-30-4 test painted on intonaco, Zecchi's blue stayed blue 4 months later.
On 4-16-4 I bought Sinopia's lime stabilized ultramarine dark and did a lime jar test on it. On 5-21-4 it was still blue.
BUT.. the on the 5-21-4 lime painting test the Sinopia blue got lighter by 9-1-4.
Ok.. I'll do a fresco test using both colors side by side, one in the lime and one on the lime in both colors. In the meantime I'll make my ultramarine blues with Thalo blue PB15.6 and cobalt blue light mixed together.
9-6-4. Here it is, lime in and lime on Sinopia and Zecchi ultramarine blues, Zecchi in the left corner, PB15.6 with cobalt blue light and a touch of titanium white in and on lime in the middle and Sinopia's ultramarine dark stabilized for lime on the right. Notations in titanium white.

blue lime test

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