O C TO B E R / N OV E M B E R 2 0 0 3 S C R A P B O O K R E TA I L E R 1 3 3

SC

IEN

CE

OF

SC

RA

PB

OO

KIN

G

SCIENCEof Scrapbooking

Preservation Q&A

BY DANIEL BURGE

W H AT A R E M O L D A N DM I L D E W A N D W H E R E D OT H E Y C O M E F R O M ?

Mold and mildew are both fungi. Unlikeplants that make their food using chloro-phyll, fungi get their food by digestingthe living or dead organic matter onwhich they live, and they do not needenergy from light to grow. They thrive inareas of high humidity and plentifulfoodstuffs. Unfortunately, they are ratherpartial to eating scrapbooks. The twoterms, mold and mildew, are often usedinterchangeably. Biologists may havetechnical meanings that separate the two;however, for simplicity’s sake, I will useonly the word mold.

As mentioned above, molds need bothhigh humidity and food. But like any liv-ing thing, it has to be borne from somethingsomewhere. Molds are carried from placeto place through the air as spores. Thesespores are like microscopic seeds that,once planted, develop into a growingmold colony. Even in areas where no moldis visible, spores still exist and are readyto infest your memorabilia. If mold is wetand slimy it is active, but if it is dry anddusty it is probably inactive. Be carefulwhen testing for activity that you don’tbrush dry, inactive mold into the air whereit can spread or be inhaled, or smear wet,active mold across the page.

Mold is not only ugly, but it alsoexcretes enzymes that digest their food-stuff. In the case of paper, this would bethe cellulose fibers and organic sizingagents. This digestion weakens the paper,robbing it of its function as a support.Molds can also excrete colored substancesthat cause stains. In the case of photo-graphs, the harm done would be to thegelatin coating that holds the image.Mold on gelatin is particularly damaging.It digs down into the photo makingremoval very difficult.

H OW D O E S M O L D G R OW ?

When you plant a flower or vegetableseed, it takes a while before you seesprouts stick up from the ground. It alsotakes a while for mold spores to begingrowing into mold colonies. This periodof time is referred to as germination. Thetime it takes for germination is variable,but it is largely dependent on the tem-perature and humidity of the envi-ronment. The higher the humidity, thefaster the germination will occur. This isalso true for temperature, but higher tem-perature won’t speed things up as muchas higher humidity.

In the table, Figure 1 (see page 134),the effect of humidity on time to germi-nation is very clear. At humidities less than65% molds usually cannot grow. Forthose of us whose natural environmentsare relatively dry (like Phoenix or Denver),

Controlling humidity to prevent mold will also help in other ways toensure that your scrapbooks and photos last a long time.

Q : I A M F R O M H AWA I I W H E R E I T I S V E RY WA R M A N D

H U M I D A L L Y E A R L O N G . M A N Y S C R A P B O O K E R S H E R E

S T RU G G L E W I T H M O L D A N D M I L D E W G R OW I N G O N

T H E I R A L B U M S . I S T H E R E A N Y T H I N G W E C A N D O TO

P R E V E N T T H I S ?

— K RYS T I K U R A S H I G E , A L O H A S C R A P B O O K I N G

A : Many scrapbookers will never experience mold or mildew in their

albums. It is possible though, as Krysti has found out, especially in the

warmer, wetter areas of the country. If mold or mildew does begin to

grow on and mar your customers’ albums, it is in your best interest to

already have some helpful solutions to help them through it. Better

yet, offer tips now on how to prevent it in the first place.

Note: a special case of mold occurs when there has been a flood. Scrapbookers everywhere are at risk for thistype of mold. We’ll deal with this as well as other flood issues in a future article.

1 3 4 S C R A P B O O K R E TA I L E R O C TO B E R / N OV E M B E R 2 0 0 3

SC

IEN

CE

OF

SC

RA

PB

OO

KIN

G

mold is not much of a problem. For thosewhose natural environment is usually wetand hot (like Miami and Hawaii), moldcan be a constant struggle. Thankfully, thetimes listed in the table aren’t the times itwill take to see a big, ugly mold colony.They simply represent the time it takes forthe spores to begin growing into actualmold. It may take a while until you actu-ally see anything yucky.

What about people who live in envi-ronments that are sometimes dry andsometimes wet? Most people do not live inconsistently dry or consistently wet envi-ronments. In my home in upstate NewYork, it tends to be very humid during thesummer months and very, very dry duringthe winter. This is because I have no dehu-midifier during the summer, and the forcedair heating system I use during the winterdries the air to 20% RH or less. The ques-tion is, are my photos and paper memo-rabilia sensitive to mold growth during theshort, moist summer?

The answer is yes and no. Moldgrowth will be dependent on whether themoisture is high enough for long enoughto germinate and develop the colony. Forexample, let’s say the average temperaturewill be 70° in my home and that thehumidity will be consistently above 75%RH for the month of July. Will that beenough for mold to grow? According tothe table, time to germination will be 38days. If the temperature and humiditydrop at the beginning of August, then the70° and 75% RH for the 31 days in July

would not have been long enough formold to germinate.

However, it is possible for mold tobegin growing from spores at high humid-ity and then continue to grow even thoughthe humidity drops somewhat. It is alsopossible for some spores to remain dor-mant for years until they have enoughmoisture to begin mold growth. Spores arereally resistant to great variations in tem-perature and humidity, so, while dry airmay kill the mold, the spores will survivein a dormant state.

H OW C A N YO U P R E V E N T M O L D ?

Our controls over mold are humidity, air-flow, and cleanliness. Reducing the mois-ture in the air around our scrapbooks willsignificantly reduce the chance that moldwill grow on our scrapbooks. Moving airencourages evaporation of moisture fromthe surface of scrapbooks and memora-bilia. Keeping storage area surfaces cleanand dry will also help prevent coloniesfrom developing.

H OW TO M E A S U R E H U M I D I T Y

Determining how the temperature andRH behave over time will help you use thetime-to-germination table to determine ifyour scrapbooks are at risk. Calling yourlocal weather station for temperature andhumidity data would only tell you whatwas going on outside your home. Tomeasure the temperature and humidityinside your home you will need special

tools. But don’t worry. They are not tooexpensive, and they are easy to use.

There are many devices available tomeasure the humidity inside your homeor storage area (such as a closet). Youknow that a thermometer measures tem-perature, but a hygrometer is what is usedto measure relative humidity. Weatherinstrument supply stores (there are manyon the Web) sell a variety of thermome-ters and hygrometers. The easiest to use,and probably most accurate, are thedigital, electronic versions. Combinationtemperature/hygrometer units are avail-able. Some even have remote sensors formeasuring temperature and humidity out-side or in different rooms around thehouse. This is what I use. Keeping a re-mote sensor with your scrapbooks andphotos can help you keep an eye on highmoisture threats to your memorabilia.

C O N T R O L L I N G H U M I D I T Y

The easiest way to control the humidityaround your scrapbooks is simply byavoiding putting them in areas that arenaturally humid in the first place. Themost humid place in the home is usuallythe basement. The moisture levels in thebasement can be significantly higher thanthe rest of the home. Dehumidifiers can do a good job of preventing mold fromgrowing in a basement. You do have tokeep an eye on them. If they break down,even for a few days, the moisture level inthe basement can become so high thatmolds germinate and begin to form

T I M E TO G E R M I N AT I O N ( I N DAYS )

65%RH 70%RH 75%RH 80%RH 85%RH 90%RH

60ºF NO RISK NO RISK 43 15 7 4

65ºF NO RISK 168 40 14 7 4

70ºF NO RISK 163 38 13 6 4

75ºF NO RISK 157 37 13 6 4

80ºF NO RISK 154 36 13 6 4

Figure 1

Not all mold is actively growing andconsuming food. If the mold is wet andslimy it is active, but if it is dry and dusty it is probably inactive.

Continued on Page 136

1 3 6 S C R A P B O O K R E TA I L E R O C TO B E R / N OV E M B E R 2 0 0 3

D E H U M I D I F I E R S

There are two ways that dehumidificationsystems can remove moisture from the air:desiccation and refrigeration. Desiccationis not a good method for reducing humid-ity in homes. That would involve usinghuge amounts of a desiccant like silica gelto trap moisture out of the air. You mayalready be familiar with silica gel, as it isused in some pharmaceutical containers tohelp preserve the medicine or vitamins. Itis also used in the packaging of many elec-tronic devices to keep sensitive instrumentsdry. In room-sized dehumidification sys-tems, silica gel can be used, but becausesuch large amounts are needed andbecause it has to be occasionally rechargedit’s not practical for the average scrap-booker. For home use, the next method,refrigeration, is more appropriate.

Air conditioners and refrigeration de-humidifiers operate on the same basicprinciples. In these mechanisms, coolantflows through a matrix of flat pipes caus-ing the surface of the pipes to be colderthan the air in the room. Blowing airacross the cold pipes cools the air andtherefore the room. But because the pipesare colder than the dew point of the air(the temperature at which water vaporcondenses) being blown across them,water condenses from the warm intake airand forms droplets on the pipes that thenare drained out of the air conditioner ordehumidifier. The amount of air moistureis thus reduced.

Air conditioners are different fromdehumidifiers in two ways. First, the heatgenerated by the mechanism in an airconditioner is dissipated outside thehome, while the heat from a dehumidifierstays in the home. The reason that theheat from a dehumidifier is not ventedoutside is that it is used to reheat the coldair back up to room temperature. De-humidifiers cannot cool your house. Sowhy would you use a dehumidifier asopposed to an air conditioner? There aretimes where air conditioners won’t beable to handle the moisture load. A dehu-midifier will be more reliable. If you

Our controls over mold are humidity, airflow,and cleanliness. Reducing the moisture in the air around our scrapbooks will significantlyreduce the chance that mold will grow on our scrapbooks and album covers.

SC

IEN

CE

OF

SC

RA

PB

OO

KIN

G

colonies. It is for this reason that it is stillprobably best to keep scrapbooks andmemorabilia out of the basement and inthe living areas of the home.

Use venting fans in the bathroom andkitchen to eliminate moisture that is created in bathing, showering, and cook-ing. The moisture in these rooms tends tomove into other areas of the home,either quickly through obvious openingssuch as doorways or slowly though thewalls. It’s also a good idea to vent clothesdryers outside the house. In the winterthough, venting inside the home can helpprevent conditions that are too dry. Justmake sure to change back in the spring.

O C TO B E R / N OV E M B E R 2 0 0 3 S C R A P B O O K R E TA I L E R 1 3 7

SC

IEN

CE

OF

SC

RA

PB

OO

KIN

G

monitor your indoor humidity, you willbe able to tell if your air conditioner issufficient to keep the humidity down.

I am often asked if small packets of sil-ica gel could be placed inside boxes withphoto materials or albums to keep thehumidity down and reduce the chance ofmold. It is likely that this method will notprove successful. For it to work therewould have to be enough silica gel to notonly dry out the air in the box but alsopull out all the moisture in the scrapbooksand photos themselves. Scrapbooks arehygroscopic, meaning that they naturallyabsorb and retain water from the atmos-phere. It would take more than a littlepack of silica gel to dry them out. The boxtoo, would have to be completely sealed.If it weren’t completely sealed, the silicagel would attempt to dry out not only theair inside of the box but the air out of thebox as well. Another option would be to keep the albums inside large sealedZiploc® bag (that would be attractivewouldn’t it?) with packets of silica gel. Ofcourse, if the album were originally cre-ated in high humidity, the silica gel wouldstill have to be strong enough to pull outany moisture already stored in the album.

K E E P T H E A I R M OV I N G

Another way to reduce the moisturearound your scrapbooks is to keep the airaround them moving. Air circulation helpsprevent mold growth through evapora-tion. This is how fans cool your body inthe summer. The air blowing across yourskin evaporates your sweat and cools youdown. Moving air may also help keepsmall, local areas sensitive to high humid-ity get drier air from adjacent places in thehome. The average humidity of the entirearea will go down. Other places to watchfor are closets, especially those with wallsadjacent to the outside. Cold walls cancause higher humidity or even condensa-tion. If the door to the closet is kept closed,humidity can build up. Also avoid closetsadjacent to bathrooms or kitchens wherehumidity can be high. I personally hadsome boxes containing photos damaged

by moisture moving through the wallfrom my bathroom into the closet.Luckily, I caught it before the photosinside the boxes were damaged or moldcould begin to grow.

K E E P T H I N G S C L E A N

Mold can also grow inside air condition-ing units. They need to be kept clean.Change filters and clean coils. Mold canalso grow in ductwork. These too shouldbe kept clean. Quality air purifiers canhelp reduce the number of spores in theair, but keep in mind that while keepingthings clean is important, reducing hum-idity is still the priority. Mold can stillgrow in a clean, but wet, environment. Agood example is the mold growth thatoccurs in bathrooms.

What do you do with moldy scrap-books, photos, and paper memorabilia?

Here are some steps to deal with moldthat has already developed. Wear rubbergloves when handling moldy materials.Dust masks may reduce, but won’t elimi-nate, the potential for inhaling moldspores. Special HEPA filter masks areneeded. Isolate affected memorabilia.Replaceable items should be discarded.Throw away infected storage materialssuch as boxes. Determine the source ofmoisture. Measure the humidity andcheck for standing water or condensation.Find a drier storage area or reduce themoisture levels of the original areathrough ventilation and/or dehumidifica-tion. Clean walls, floors, and shelvingusing mold killing cleaners like Lysol® orClorox®. Just make sure to use thesesafely and keep the area well ventilated.Active mold should not be wiped as thestaining may spread.

One recommendation is to put the moldy surface out in sunlight for 30 minutes. Longerperiods may begin to fade colors and damagepaper fibers.

1 3 8 S C R A P B O O K R E TA I L E R O C TO B E R / N OV E M B E R 2 0 0 3

SC

IEN

CE

OF

SC

RA

PB

OO

KIN

G When it does happen, very gently liftingthe plastic up from the surface of thephoto will usually separate them.

High humidity can also cause inks tobleed. These can be inks applied to thepage by pens or stamps, or it can be inksfrom computer printers. Inkjet printersoften use dyes that are sensitive to highhumidity. These dyes are used for text,graphics, and photographic images.Bleeding inks can transfer the image toadjacent materials or migrate across thesurface of the print making the picturelook fuzzy. The same thing can happen topen and stamp inks. Controlling humidityto prevent mold will also help in otherways to ensure that your scrapbooks andphotos last a long time.

Daniel Burge is a Research Scientist at theImage Permanence Institute at the RochesterInstitute of Technology. He has been investi-gating the potentially harmful interactionsbetween photo storage products and photo-graphs for the last 12 years. He is also activeas a member and educator in the ScrapbookPreservation Society.

H OW TO C L E A N M O L D F R O M S U R FAC E S

After deactivation, a vacuum can be usedto pull most of the mold from the surfaceof the scrapbook or photo. Place thepages, sheets, or photos under a wirescreen so that you don’t destroy thepage. Home vacuums are powerfulenough to crumple paper sheets. Test theprocess with either the most badlyaffected or the least valuable. Make surethe vacuum cleaner bag can trap moldspores. If in doubt, do the vacuumingoutside. You don’t want to spread themaround your house. Dispose of the vac-uum cleaner bag promptly.

M O R E H I G H -H U M I D I T Y P R O B L E M S

High humidity can cause many otherproblems besides mold for your scrap-books and photo collections. Theseinclude paper degradation, metal corro-sion, photo sticking, and ink bleeding.Paper degradation and metal corrosionoccur slowly over the long-term. Photosticking, called blocking, can occur rela-tively quickly at high humidities. Thisoccurs when high humidity and tempera-ture cause the surface of the photo tosoften and become tacky. It then acts likeglue adhering to any smooth surface itcomes in contact with. Sometimes thishappens in frames, if the photo wasmounted directly in contact with the glass.When this occurs, it is often impossible toseparate the photo from the glass. It canalso happen to photos in contact withpage protectors, but not as easily becauseof lubricants on the surface of the plastics.

Deactivate mold by moving the moldyobjects to a drier area or exposing it toUV radiation (see below). After deactiva-tion, clean the mold from the surface (seebelow).A professional conservator shouldtreat valuable, fragile, or seriously dam-aged heirlooms. Professional conservatorscan be found through the American In-stitute for Conservation by phone (202)452-9545, ext. 1 or on the Web at http://aic.stanford.edu/faic/refer.html. An openbox of baking soda can help removeodors. Finally, monitor for mold regrowth.

H OW C A N YO U K I L L M O L D ?

Sunlight reduces mold growth. It is theultraviolet radiation (UV) in sunlight thatkills many molds. The UV from fluores-cent bulbs will do the same thing. Butremember, UV does not kill spores; itonly kills active mold. One recommen-dation is to put the moldy surface out insunlight for 30 minutes. Longer periodsmay begin to fade colors and damagepaper fibers. Taking your precious mem-ories outdoors is risky, though, especiallyif it’s really humid.

There are some chemicals that can beused to kill molds. However, if the condi-tions that caused the mold still exist, itwill only return again. Also, the chemi-cals may not be safe for your scrapbook,and most of these products are poison-ous. Using dry air to kill mold is the bestapproach. Do not attempt to dry themold quickly with a hot air source like ahair drier, as that can cause materials tobecome deformed. Find a dry, room-tem-perature environment instead. Monitorthe mold until it becomes inactive.

T H E L E A S T YO U N E E D TO K N OW :

� Retailers should be prepared to deal with customer mold problems.

� The first sign of mold infestation may be a musty odor.

� Mold is dependent on humidity.

� The paper and photos in scrapbooks are good sources of food for mold.

� Mold may be a health hazard.

� The greatest risk for mold in the home is in the basement.

� High humidity also causes paper degradation, metal corrosion, photo sticking,and ink bleeding.

� The best way to prevent mold and to slow other scrapbook decay processes is to keep the air dry.