Presentation given at the Royal Society of Chemistry ChemCareers 2011 postgraduate competition final.

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CENTRE FOR SUSTAINABLE HERITAGE
Stability of Colour
Photographs in Mixed
Archival Collections
Ann Fenech
ChemCareers 2011 Postgrad competition

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Research Questions
• What are the principle degradation
factors in the storage environment?
• Can the stability of chromogenic
prints be characterised in a rapid
and non-destructive manner?
• How is material change perceived
by users of archival photographs?

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Context: The National Archives
What materials are
stored in boxes?
75% paper,
0.7% photographs
99% of original record
available within 60mins Information it contains
What are the public service How is the material to
standards expected? be archived chosen?

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Looking at what causes change
THE ARCHIVAL ENVIRONMENT

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Environmental Conditions in Archives
Temperature
?
Relative
Pollutants
Humidity
Temperature & RH: continuously monitored in archival collections
Pollutants: sporadically monitored, if at all

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The Archival Environment: Pollutants
140 Ozone
130 Nitrogen Monoxide
120 Nitrogen Dioxide Indoor generated pollutants, particularly
110 Sulphur Dioxide acetic acid, by far the most abundant
100 tVOCs pollutants within archival boxes
Concentration (ppb)
90 Acetic Acid
Volatile Aldehydes
80
Formaldehyde
70
60
50
40
30
20
10
0
External Environment Repository Archival Boxes
Fenech A, Strlič M, Cigid IK, Levart A, Gibson LT, de Bruin G, Ntanos K, Kolar J, Cassar M (2010)
‘Volatile Aldehydes in Libraries and Archives’ Atmospheric Environment 44(17): 2067-2073

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Looking at Change
Materials Research

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Dye Analysis
Chromatography
Developed methodology for extracting and separating
photographic dyes
Colorimetry
Compared spectroscopic data of individual dyes extracted from a
photograph to colorimetric data obtained prior to extraction
Non-destructive Monitoring of Dye Concentrations
Identified sRGB as the best colour system to monitor changes in
dye concentrations
Fenech A, Strlič M, Degano I, Cassar M. (2010) ‘Stability of Chromogenic Prints in Mixed
Archives’ Polymer Degradation and Stability 95(12): 2481-2485

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0.12
Effect of Pollutants 0.10
R
G
B
0.08 Rate of Change (Day-1)
0.06
Rate of Change
0.12
0.04
0.10
Conditions of Ageing 0.02
Closed vial ageing 1998, unknown 0.08
0.00
Temperature: 80 °C 0.06
-0.02
RH: 60% 0.04
R
G
Control Acetic Acid Formaldehyde Nitrogen dioxide
-0.04
Pollutant: 250 ppb B
Rate of Change
0.12
0.02
0.11 Control Acetic Acid Formaldehyde Nitrogen dioxide
2000, Fujifilm 0.10
0.00
0.09
0.08
Acetic acid causes the -0.02
0.07
greatest rate of change 0.06
-0.04 R
0.05 G
and is also the most 0.04 B
Rate of Change
abundant pollutant in 0.03
0.02
archival boxes. 0.01
2005, Kodak 0.00
-0.01
-0.02
Control Acetic Acid Formaldehyde Nitrogen dioxide
-0.03
-0.04
Fenech A, Strlič M, Degano I, Cassar M. (2010) ‘Stability of Chromogenic Prints in Mixed
Archives’ Polymer Degradation and Stability 95(12): 2481-2485

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Experimental Methodologies
Traditional Experimentation Statistical Experimental Design
x varied; y and z constant
y varied; x and z constant
z varied; x and y constant
y
z
x
k=f(x)+f(y)+f(z) k=f(x, y, z)
Statistical experimental design principles for designing degradation studies
provides information on factor effects as well as factor interactions

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Degradation Studies
@ 80 °C
ΔERGB /year
*
Fenech A, Strlic M, Ntanos K, Bell N and Cassar M. (2011) Lifetime of Chromogenic Colour Photographs in Mixed Archival Collections
Preprints 16th Triennial Conference Lisbon, 19-23 September 2011, ICOM International Committee for Conservation

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Looking at how change is perceived
Determining Damage

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Assessment workshops based on
psychophysical principles carried out with
stakeholders to answer the following question:
How do you evaluate the information content in the
degraded colour photograph in comparison to the
original?
Favourable [5]
Acceptable [4]
Just Acceptable [3]
Unacceptable [2]
Poor [1]

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NO
YES
Do assessor characteristics affect Do image characteristics affect
acceptability outcomes? acceptability outcomes?
• Job • Content Type (landscape,
• Experience people, technical)
• Interests • Age of original image
• Knowledge rating • Fading Profile (selective dye
fading vs equal dye fading)
• Detail in image

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Summary
Environmental monitoring at TNA to Accelerated degradation experiments
identify the most abundant under different environmental
pollutants conditions to investigate image stability
Non-destructive material Lifetime determination based on
characterisation using colorimetry acceptability considerations
determined by stakeholder input