Study for approaching mold problems on photographic materials using antifungal agent and enzyme sheet
Yoko Shiraiwa and Takako Yamaguchi
Introduction
The poster shows two approaches to mold problems concerning photographic materials. The first continuing study uses the antifungal agent, Hokucide® R-150 to prevent mold on water damaged
photographs when freezing and drying may be difficult after disasters. The second, Biofree® enzyme filter sheets, is being tested to prevent and suppress mold contamination on photographic materials.

Examination of an Antifungal Agent for Use on Photographs

Study of using Biofree® enzyme filter sheets to prevent fungal problems

Antifungal Agent Hokucide® R-150 (Hokko Chemical Industry Co., Ltd, Japan) is an aqueous solution of chloromethylisothiazolinone andmethylisothiazolinone. Widely used in the architectural industry as an antibacterial and antifungal agent for construction materials, adhesives, paints,coatings, paper, and silicone oil. Used to control the germination of bacteria, fungi, algae and yeast and a surfactant is usually added to Hokucide® R-150for even dispersion and reduction of surface tension.

What is it ? How does it work?

Testing Hokucide® R-150 solutions on photographic materials for long term effectHokucide® R-150 solutions used for the testSolutions withAfter

After

After

After

Hokucide R-150 (%)

immersion

4 days7days

14 days

Distilled water (1.5)
control

-0.11

-0.08

-0.16

-0.02

Fuji Driwel K (1.5)

-0.11

-0.13

-0.17

-0.11

Kodak Photo-Flo (1.0)

-0.13

-0.13

-0.16

-0.15

ーー-0.01-0.10

Ethanol (1.5)

Table 1.

Gelatin silver print (DOP)
2.5
Control
1.5% R150+ DRIWEL
1.0% R150+ PHOTO-FLO

2.01.51.00.5Reflection density Dg

Change in transmission density (ΔTDb）Colloidal Silver Filmwith initial transmission density(after accelerated aging for 14 days)*For the solution with ethanol, 1 and 3 weretested.

Reflection density Dv

Method - Accelerated Aging Test
★ Wash samples in distilled water, immersed insolutions and dry. Place in a chamber for
accelerated aging (at 60°C/140°F, 86%RH forcolor materials and 70°C/158°F, 86% RH for therest).
★ Reflection density and colorimetric measurementsof CIE L*a*b* values were measured using aspectrophotometer before and after immersion,and after 7 days and 14 days of accelerated
aging.
★Resolution charts were viewed under optical
microscope (100x) at each stages to observe anychanges in details.

Observations and Results
1 Transmission density changes (ΔTDb) minimal(Table. 1).
2 Reflection density change values for samples
similar to the control (Fig. 1), except for POP,
which had a slight change in the middle tone
area (Fig. 2).
3 For the Photo-Flo solution samples ; slightchange of color (ΔE*ab) in magenta:+2.44(+1.01 for control) and a yellow stain in white:+3.55 (+1.58 for control). Other ΔE*ab values
remained between 0.19 and 1.76 after 14 days.
4 No loss of detail observed in resolution charts.

Samples
1 Colloidal Silver Film
2 Monochrome prints (step tablet) :Albumen print, Gelatin silver POP,Gelatin silver DOP on baryta
3 Macbeth Color Chart (chromogeniccolor)
4 Resolution Charts of monochromeprints(after accelerated aging for 14 days)

1.5% Hokucide® R-150 with Fuji Driwel K (1% v/v)
1.0% Hokucide® R-150 with Kodak Photo-Flo (0.5% v/v)
1.5% Hokucide® R-150 with ethanol (5% v/v)
Ethanol was also tested as an alternative to photographic
surfactants which are more difficult to obtain.

Gelatin silver print (POP)2.5Control
1.5% R150+ DRIWEL
1.0% R150+ PHOTO-FLO

2.0
1.5
1.0
0.5

0.0
0.0 0.5 1.0 1.5 2.0 2.5
Reflection density Dg (before immersion)

0.0
0.0 0.5 1.0 1.5 2.0 2.5
Reflection density D (before immersion)

Fig.1

Disaster in Japan (2011 Earthquake and Tsunami) resulted in a widespread loss of basic infrastructure with shortage of supplies for several weeks.
Important to find a way in which this agent can be used effectively with a limited water supply. The antifungal effect of Hokucide® R-150 of simple spraying
as well as soaking was evaluated.
Samples
1.Gelatin silver DOP on baryta
2.Developed black and white negative
film (only with ethanol solution)

Results of fungal growth
Driwel K
fungi

fungal growth
after -- week

Control

Aspergillus
niger

1 weekControlEuroteum
herbariorum

1 weekHokucide®
R-150
Driwel K andPhoto-Flo

Aspergillus
niger

9 weeks

Hokucide®
R-150
Driwel K andPhoto-FloEuroteum
herbariorum

14 weeks

Hokucide®
R-150
Ethanol

Aspergillus
niger

Not detected(2016.2.29~)

Hokucide®
R-150
EthanolEuroteum
herbariorum

10 weeks

Photo-Floethanol

Driwel K

Aspergillus niger
ControlEurotium herbariorum
Control

Aspergillus niger
Spray

Eurotium herbariorum
Spray

Aspergillus niger
ImmersionEurotium herbariorum
Immersion

Characteristics of enzyme sheets as a sustainable method for preventing and suppressing moldcontamination on photographs✤ Lytic

enzyme, an active ingredient, is immobilized on the filter media by chemical bonding thereby prevents physicalseparation from the filter media.

✤ No energy required to activate.
✤ No frequent changing required.
✤ Soft and flexible non-woven fabric (rayon), easy to handle and use.
✤ Safe for the environment and human health.
✤ Cost effective.
✤ P.A.T. passed. (ISO 18916:2007)*The sheet must be in direct contact with the object in order to exhibit its effect, therefore P.A.T. was conducted in 2015.

Effect of enzyme filter sheets on photographic prints contaminated with fungi
Samples (Eurotium herbariorum)

Method A★Place enzyme sheet onto photographs heavily
contaminated with fungi; in this case,
Aspergillus niger and Eurotium herbariorum.
★Cut out a small square from each print as
control, cover the rest with the enzyme sheet.
★Place in a chamber at 27°C/80°F and90-100%RH for 10days.

Gelatin Silver DOP on baryta / Macbeth Color Chart (chromogenic color)
control

sheet

control

sheet

Fig. 2

Antifungal effect by spraying and soaking Hokucide® R-150 solution

Method★Prepare groups of prints: control, spray with solution, immerse in solution.
★Place onto prints, spores of fungal strains Aspergillus niger and Eurotium herbariorum (paper disks).
★Place petri dishes with prints in a chamber at 27°C/80°F and 90-100%RH until fungal growth detected.

Enzyme sheets are widely used as filters in air conditioning systems. Their primary function is to kill airborne microorganisms caught on
their surface to protect against secondary contamination. Against bacteria, they dissolve the binding sites of a cell membrane byhydrolysis and then burst the cell membrane. Inner osmotic pressure then causes cell death. Against fungi, they deactivate the hyphae
and maintain a bacteriostatic effect to suppress further fungal growth and contamination. Biofree® is manufactured by Nikki-Universal Co.,
Ltd. Japan.

Photo-Flo

Method A - Observation and result
Samples observed under a Scanning Electron
Microscope.
Compared with control;•Spores dispersed and scattered, some lookcrushed.
•Some individual spores shrunken or contracted,changing their shapes and size.
•Some hyphae lost their distinctive shape.
These observations cannot confirm whether
fungal activity has been suppressed or not,however dramatic changes in shapes of sporesand hyphae noticed.

200x200x

200x200x

ethanolConclusion
The study suggests a method to be considered in preventing a mold outbreak. The results confirm that Hokucide® R-150 solution with a surfactant(Fuji Driwel K, Kodak Photo-Flo) or ethanol can suppress microbial damage to photographs and furthermore, does not show any significant
negative impact on the photographic materials after accelerated aging. To conserve water during emergency situation, spraying the solution proved
to be an effective application method. The solution is simple to make, easy to use, and can be sprayed on. Great benefit when treating large
numbers of objects during emergency recovery.

Method B★ Place two paper disks with spores of fungal strains on each prints. (Aspergillus
niger and Eurotium herbariorum)★ Leave one disk uncovered as a control and cover the other disk with theenzyme sheet.
★ Place in a chamber at 27°C/80°F and 90-100%RH until fungal growth detected.

Method B- Observation and result
First 7 days mold growth more apparent on thecontrol; after 14 days, mold growth seen on all
samples. Due to the high humidity(90-100%RH), the sheet absorbed excessive
moisture.

Conclusion and further research
Changes observed on the configuration of fungi spores and hyphae in contact with sheets. Further investigation is necessary to judge
effectiveness of the enzyme sheets.
-Monitor long term effects under normal circumstance as opposed to accelerated tests. Elevated humidity causes condensation on thismedia.
-Test using spore fluid, rather than disks with spores, as the enzyme sheet needs to be in close contact with the object.
-Cultivate the fungal strains which were in contact with the sheets to see how the shapes and growth differ from the ordinary strains.
Yoko Shiraiwa, Paper and Photograph Conservator

Takako Yamaguchi, Conservation Scientist

Shiraiwa Conservation Studio
www.shiraiwaconservation.com / ys-i@gol.com

Tokyo Photographic Art Museum
www.topmuseum.jp / t.yamaguchi@topmuseum.jp