Skip to main content

Table 2 Overview of mock-up sets before cleaning and cleaning systems tested per mock-up type

From: Evaluation of novel cleaning systems on mock-ups of unvarnished oil paint and chalk-glue ground within the Munch Aula Paintings Project

Mock-up sets Typea Ageingb ‘Pre’ cleaning Layer thicknessc Chalkingd rating Water-sensitivitye rating Cleaning systems tested
Stage one: cleaning trials
 M1
 33 in total
G 1 week
30,719 kJ/m2
n/a n/a 2 4 Options tested—SPB: wheat starch, Arbocel® A and Arbocel® B. Free liquid trials: DI water, pH and conductivity adjusted waters, buffered waters, chelating agents, surfactants. Nanorestore Gel® Peggy and Dry series: HWR, MWR, Peggy 5 and Peggy 6
Pu 1 week
30,719 kJ/m2
n/a n/a 1 3
Pd 1 week
30,719 kJ/m2
n/a n/a 2 4
Stage two: comparative cleaning tests
 M2
 72 in totalf
G 4 weeks
143,349 kJ/m2
Bread loafg Ave.136 µm
Min 44
Max 338
SD: 76
2 4 SPB: Arbocel® A
CO2-snow: gas source
Nanorestore® MWR gel, 0.5% w/v citric acid/NaOH pH 6.5, 4.4 mS/cm. Clearance: MWR with water adjusted to pH 6.5
PU sponge: white, latex free
Pu 5 weeks
159,521 kJ/m2
Bread loafg Ave. 239 µm
Min 176
Max 320
SD: 38
1 3 SPB: Arbocel® A
CO2-snow: gas source
Nanorestore® Peggy 6 gel, 1% w/v citric acid/NaOH pH 6.5, 9.2 mS/cm. Clearance: Peggy 6 with water adjusted to pH 6.0
PU sponge: white, latex free
Pd 5 weeks
159,521 kJ/m2
Bread loafg Ave. 29 µm
Min 11
Max 56
SD: 13
2 4 SPB: Arbocel® A
CO2-snow: gas source
Nanorestore® MWR gel, water adjusted to pH 6.0, 1000 µS/cm. Clearance: not required
PU sponge: white, latex free
  1. aG = chalk-glue ground, Pu = undiluted cobalt blue oil paint, Pd = turpentine diluted cobalt blue oil paint. All mock-ups were composed of the following: linen canvas, hide glue size, chalk-glue ground. Pu and Pd had an additional upper layer of oil paint
  2. bArtificial ageing: Xenon-arc lamps indoor window glass filters, irradiance of 30–50 W/m2 (300–400 nm), Black standard temperature (BST) 45 °C, chamber temperature (CHT) of 30 °C, and RH 65%
  3. cAverage of 300 measurements from 6 samples of each type. The layer thickness influences the vulnerability of the surface to dry mechanical and aqueous cleaning action
  4. dUNI EN ISO 4628-6 (2011)—part 6: assessment of degree of chalking by tape method. The rating from 0 to 5 (5 = most chalking) is based on the amount of pigment particles noted on an adhesive tape after peeling it off the painted surface and comparing it to a visual reference scale in the standard. See also Additional file 2: Table S1
  5. eMills et al. [46]. DI moistened swab rolls. Rating from 1 to 5 (5 = most water-sensitive)
  6. f12 for cleaning tests and 12 controls (3 unsoiled, accelerated aged; 3 soiled, accelerated aged; 3 unsoiled, naturally aged; 3 soiled, naturally aged)
  7. gUnsoiled, naturally aged controls were not bread cleaned