under what expectations is a photograph expected to perform
Temperature and RH monitored by TNA staffPollutants needed to be monitored
What did I find?Outdoor generated vs indoor generated.Indoor generated much more abundant
Having identified which pollutants are most abundant: acetic acid and nitrogen oxides, and having developed a non-destructive way for monitoring these changes, I could then start looking at the effects of a number of environmental factors relevant to an archival environment on these materials.Acetic acid and nitrogen oxides seem to be the ones which are causing greatest degradation. However, in light of the fact that acetic acid is present in concentrations around 10 times higher than nitrogen oxides, acetic acid was prioritised as the pollutant for further studies.
Traditional Experimentation:You keep all factors constant, and then vary one. Then keep all other factors constant, and change another, and so on and so forth till you have varied all factors.
Multi-parametric damage functions
under what expectations is a photograph expected to perform
So now we have data on environmental conditions inside archives, on the effect of various environmental conditions on these materials, and end of useful lifetime, all the data can be pulled together to provide a holistic look at a collection.
Stability of Colour Photographs in Mixed Archival Collections
CENTRE FOR SUSTAINABLE HERITAGECENTRE FOR SUSTAINABLE HERITAGE Stability of Colour Photographs in Mixed Archival Collections Ann Fenech ChemCareers 2011 Postgrad competition
CENTRE FOR SUSTAINABLE HERITAGE 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?
CENTRE FOR SUSTAINABLE HERITAGE 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?
CENTRE FOR SUSTAINABLE HERITAGE Looking at what causes change THE ARCHIVAL ENVIRONMENT
CENTRE FOR SUSTAINABLE HERITAGE Environmental Conditions in Archives Temperature ? Relative Pollutants Humidity Temperature & RH: continuously monitored in archival collections Pollutants: sporadically monitored, if at all
CENTRE FOR SUSTAINABLE HERITAGE 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
CENTRE FOR SUSTAINABLE HERITAGE Looking at Change Materials Research
CENTRE FOR SUSTAINABLE HERITAGE 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
CENTRE FOR SUSTAINABLE HERITAGE 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 0.10Conditions of Ageing 0.02Closed vial ageing 1998, unknown 0.08 0.00Temperature: 80 °C 0.06 -0.02RH: 60% 0.04 R G Control Acetic Acid Formaldehyde Nitrogen dioxide -0.04Pollutant: 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 0.08Acetic acid causes the -0.02 0.07greatest 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
CENTRE FOR SUSTAINABLE HERITAGE 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
CENTRE FOR SUSTAINABLE HERITAGE 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
CENTRE FOR SUSTAINABLE HERITAGE Looking at how change is perceived Determining Damage
CENTRE FOR SUSTAINABLE HERITAGE 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  Acceptable  Just Acceptable  Unacceptable  Poor 
CENTRE FOR SUSTAINABLE HERITAGE 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
CENTRE FOR SUSTAINABLE HERITAGE SummaryEnvironmental 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