Association of Manitoba Museums

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Are the old fashioned pull-down roller blinds suitable for use in museums that are in historic buildings? Can you recommend a hardware supplier?



Roller blinds are a simple, effective and historically accurate method of controlling light in older buildings. Roller blinds were commonly used in houses for approximately 300 years, beginning in the early 18th century when a couple of enterprising Scotsmen imported linen fabric from Holland and began making the first window blind using Scotch Holland cloth. Settlers brought the idea over and blinds made of heavy linen or cotton cloth would be found in many homes in the 19th and 20th century homes.  

The first roller blinds did not have the sometimes deadly spring mechanism that many of us remember from our schooldays. Instead, the wooden bar sewn into the bottom of the blind was simply raised and dropped when a cord was pulled. The spring mechanism for the roller blind was invented separately in the US and the UK in the mid-late 19th century. The company that first patented the spring mechanism in Britain still manufactures them for the National Trust’s historic buildings.

Ready-made roller blinds, made by companies such as Levolor, are available from chain stores such as Home Depot, Walmart, Canadian Tire, Sears and Rona. Ikea also sells roller blinds. They come in standard sizes, and most hardware stores will cut them down to the non-standard sizes that you find in historic houses. It is also possible to purchase ready-made roller blinds made from light filtering fabrics, room darkening fabrics, blackout fabrics and solar screening fabrics. It is usually cheaper to install a roller blind made with a thermal fabric in a single pane window than to replace the window with a double or triple pane insert.  

It is also possible to make your own blinds. Instructions for home made roller blinds can be found at The hardware is inexpensive and can usually be found at hardware stores. It is installed by means of a few screws, with minimal damage to the window frame.  


We have received a donation of a porcelain doll. Since we have a seasonal museum, I am wondering if the doll should be removed from the premises when the museum closes, or whether it can be stored properly on site.



Porcelain is made from a liquid clay formulation, moulded into greenware, and then fired at a very high temperature to become bisque. Early porcelain dolls have a one-piece head-and-shoulders section and porcelain forearms and lower legs, attached to a soft body made of leather or fabric. The face is painted with mineral-based paints that fuse to the surface of the porcelain during the kiln firing. These dolls can have beautiful painted features, elaborate moulded hairdos, and intricate costumes.

Porcelain is more susceptible to environmental changes than other ceramics. Although it is not porous, the surface can crack or craze, especially if there are rapid changes in temperature and relative humidity. The leather body and clothes may also be susceptible to environmental changes. The body is often stuffed with horsehair, which is a food/bedding material for insects and rodents.

If there is a choice, it would be better to store the doll in a heated environment than an unheated one, particularly if the porcelain is already cracked or crazed. If there is no other choice, the doll needs to be properly packed for over-wintering in a closed seasonal museum.

Wrap the doll in layers of clean cotton and place it in a nest of bunched-up acid-free tissue or more cotton, inside a box. If the doll has moveable eyes, store it face down to keep the eye-rolling mechanism working. The box acts as a buffer, slowing down changes in temperature and relative humidity. A Rubbermaid box will protect the doll from any water leaks and be easier to store and handle. If a plastic box is not the Rubbermaid brand, look for the letters PP or PE in the recycling symbol found on the bottom. This confirms that it is made from a stable polymer and will not off gas and damage the artifacts stored within. Place the box well inside of the building, away from exterior walls.

Storing the doll in this manner will ensure that it is kept dry, buffered from the extremes of temperature and relative humidity, cushioned against any physical damage, and protected from pests.

For more information, or to ask a question of our CSP conservator, contact


We have on display a leather dog collar that had been buried in the ground until dug up in the 1950s. It has recently developed a white “bloom” on the surface that we think might be mould. What can be done to clean and preserve the collar?


It can be difficult to tell at first glance whether the white bloom is mould or a surface deposit that is efflorescing on the surface of the leather. However, it is most likely a white surface deposit known as “spew”. A leather artifact affected by Spew may also shrink or become distorted.

Spew on leather is thought to be the result of an over-application of leather dressing, or the use of poor-quality or homemade dressings. As the leather dressing ages, it can redeposit on the surface of the leather it was once applied to. Alternatively, an improperly applied leather dressing can leave a surface residue that forms Spew.  

Spew does not always look the same. It has been found on wooden artifacts, where it often has a crystalline appearance. The appearance of Spew is determined by the fats or oils present in the artifact, the formulation of any finish or dressing that has been applied, and the storage conditions. Environmental conditions (temperature and relative humidity) are thought to play a role in the migration and crystallization process that results in Spew. Spew is usually found on areas of an artifact that are exposed to air. Ironically enough, your dog collar may have been safer when buried in the ground!  

Surface Spew can be carefully wiped off with a soft cloth with the aid of Q-Tips to clean out any nooks and crannies. It must be done on a regular basis as it will return. It is possible to remove Spew so that it does not return but that is a procedure best carried out by an objects conservator due to the chemicals involved. If the collar is otherwise in good condition, it is not necessary to do anything further than wipe it over carefully whenever necessary. Be sure to take the same precautions that you would with any cleaning process, using latex or nitrile gloves and disposing of the cleaning cloths and gloves in a sealed garbage bag.

At one time, it was considered a good thing to apply leather dressing to leather objects. Studies have indicated that the dressing does not actually do much good and can actually cause harm as it ages. A discussion of this subject can be found in the following Conserve O gram:
If you are interested in reading more about this condition, the following report by the British Museum shows that you are not alone in your experience with Spew:


With recent heavy rains we were wondering what we should do to prevent and recover from a wet basement or flood?


There is always a real risk of flooding in Manitoba.  

This situation could put many museums in danger of flooding or cause normally safe locations to experience waterlogged basements.  Even if a basement isn’t actually wet, it can be damper than usual and create an environment conducive to mould, especially those museums that store artefacts in a basement or below grade.  

If it appears that your institution is at risk for flooding, begin planning now.  Ask yourself and your Board the following questions:
•    How will your security, fire department and available staff/ volunteers function in the event of a flood?   
•    Does your insurance cover flood damage to buildings? To collections?
•    Is there an evacuation plan for your collections?  
•    Who will decide if the collections have to be evacuated, and how will it be done?
•    Have you a back up location where collections can be stored?  
•    If a seasonal museum, are you prepared for a delayed opening?
•    What will you do while waiting for the floodwater to recede?  Is it possible to open a satellite location?
•    What is your plan for business resumption?

To reduce the potential for water damage in your museum:
1.    Check the drainage system (storm sewer) on your street and if it is blocked, report the condition to the authority or try to unblock the sewer. If you live in a rural area, check culverts and other waterways and remove any blockages if it is safe to do so.

2.    If yours is a seasonal museum that is not yet open, or has buildings still closed up, open them up and monitor for water damage.  
3.    Make sure your sump pump is working properly. Consider installing a secondary back up pump in the event of a power failure. Make sure the batteries in the back up pump are fully charged.
4.    Keep the eavestroughs of your museum clear of debris to help drain melting snow and prevent ice from backing up under the shingles. Ensure down spouts are draining water away from the foundation.
5.    Check the basement for water on a regular basis, especially in times of heavy rain. Consider elevating artifacts off the basement floor to prevent possible water damage or move them to the upper floors of the museum.
6.    Store important papers in watertight containers in a safe place.

7.    Follow directions from your local authorities and monitor the situation in your area.

If your museum does not face actual flooding, it may still be at risk of water infiltration.  If so, the following general guidelines may help you avoid problems or minimize them if they exist:

•    If you suspect that your museum is experiencing levels of high humidity, obtain the best quality thermometer/hygrometer that you can get on short notice, place it in the affected space, and check the temperature and relative humidity readings regularly.  

•    If relative humidity reading is above 65% and stays there for several days, there is a risk of mould developing.  Use fans, dehumidifiers and portable heaters in the area to get the air moving and dry it out.

•    If you find water in your museum, locate the source of the water and take steps to stop it.  This may require the services of a tradesperson.

•    If the water in your basement contains sewage, or you see mould growing, contact your local health department for advice.  Refer to the Canadian Conservation Institute’s Note Mould Outbreak – An Immediate Response at

•    If the water is clean, drain it out if possible, using a submersible pumps followed by Wet/Dry Shopvacs, and mops.  Wear protective clothing including gloves and a mask.  

•    If you have artefacts sitting in water, locate a suitable secure storage place before attempting to move them.  A school gymnasium, a Community Centre, a dry outbuilding or a clean, dry upper floor will all do as a place to air-dry your artefacts.  You will need to put down something absorbent such as old blankets or towels.  Have fans and dehumidifiers running.  

•    Keep in mind that waterlogged artefacts can be heavy.  The glues used for older furniture can give way when wet.  The bottom can fall out a wet cardboard box.  Ceramics and glass can be slippery.  Make sure that you have plenty of volunteers to help move artefacts to a drier place.

•    Maintain intellectual control by copying information off waterlogged boxes and labels and keeping it with the artefacts.

•    Paper based artefacts (books, documents) and textiles can be bagged and frozen until there is time to safely air-dry them.

•    For help in drying water logged artefacts, view the 10 minute video, Coping With Water Damage, at

•    Keep checking the artefacts for mould until they are completely dry (several days).  Do not return artefacts to a previously-wet space until it is thoroughly dried out.  This may take several days or even weeks.

The following supplies may come in useful:

Supplies and equipment for salvage
•    Polyethylene sheeting
•    Unprinted newsprint and/or blotting paper
•    Polyethylene bags
•    Tape
•    Towels and blankets
•    Disposable masks and gloves
•    Handcarts
•    Two-wheel hand trucks
•    Milk crates or standard-size boxes

Supplies and equipment for mucking-out and clean-up
•    Detergents/Bleaches/Disinfectants/Cleaning powders
•    Brooms/Mops/shovels
•    Sponges or rags/Buckets
•    Water hoses
•    Plastic bags
•    Large window or floor fans
•    Dehumidifiers
•    Portable water pump
•    Wet/dry Shop Vac

The Association of Manitoba Museums is available to provide advice to its members on any concerns they may have regarding flooding or high levels of humidity in their buildings.  During office hours, you can contact us at 947-1782 (toll free 1-866.747.9323) or .

 In case of emergency, contact the AMM conservator anytime by email at  

Association of Manitoba Museums


Why do some instructions for freezing insect-infested artifacts tell you to take them out of the freezer, let them thaw, then put them back in? Why not just leave them in longer?



The Canadian Conservation Institute (CCI) Note 3.3 “Controlling Insect Pests with Low Temperature” is one of the best basic primers on how to freeze your artifacts to get the bugs out. It explains the basic principle of freezing, which is to put your artifacts in an environment that is colder than the infesting insect can tolerate, and to leave it there long enough that the insect cannot recover. To quote Note 3.3, A major guideline to follow when using freezing to control insect pests is to expose them to temperatures that drop as low as possible, as quickly as possible, for as long as possible. A practical recommended treatment is -20°C for one week.

One reason to undertake a second period of freezing is when an older freezer cannot freeze to the required temperature quickly enough, or when a freezer is too full and takes more time for all the contents to reach -20oC. Under these conditions, an insect can go into a dormant condition that is known as diapause whether it is an egg, a pupa or an adult. It can go for weeks, months or years in this dormant condition and awaken when conditions are more favourable – such as when you take infested artifact out of the freezer and return it to storage or display.

To see how efficiently your freezer works, try putting a Ziploc bag of water inside along with your artifacts, and see how long it takes to freeze. You can also put in a Ziploc bag containing a few live insects, and see if they recover after the period of freezing. Remember not to pack the freezer too full.

The recommendation to bag artifacts before putting them in the freezer is to protect them from condensation when they are removed from the freezer. Keeping an artifact in the bag after removing it from the freezer also allows you to check for any awakening insects after freezing. Monitor the artifact for at least a week and preferably one month. If you see any signs of insect life, repeat the freezing operation again. This is extra insurance that the freezing has actually worked.

CCI Note 3/3 can be downloaded free of charge in English or French


Our museum is located in an historic house in rural Manitoba. When we checked on it last fall after closing it up, there was a swarm of ladybugs inside on the curtains, doorframes and windows of the south side. How can we get them outside again? And how did they get inside in the first place?


Coccinellids – also known as Ladybugs - are outdoor insects with an adult lifespan of 2-3 years. At the end of the summer, they look for a warm, protected place to overwinter. Buildings that are near woods and fields are a logical choice to a ladybug. They are attracted to light-coloured houses or houses with nice warm southern exposure and will swarm onto sun-warmed structures during the fall. Many older buildings have small cracks and gaps around windows, under doors and between siding slats. The ladybugs find a way inside where they gather in groups to reproduce and hibernate. If you see one in a house in the fall, there will most likely be others.

If the ladybugs have been hibernating inside your historic house and the temperature rises, due to a sudden warm spell or the house being heated for a seasonal event, the ladybugs may think it’s spring and emerge. If you discover them, you have two choices: leave them alone or remove them. 

Ladybugs eat only insects and are not harmful to museum collections. They will find their way outside when spring arrives. You may have a housekeeping task as there will probably be a number of dead ladybugs to clean up, killed when the temperature dropped before they could re-enter hibernation mode, or when the air became too dry.

If you do want to remove them before hosting the annual Christmas levee, vacuuming them up is probably the safest and easiest method. You can use a shop vac with a clean bag, and release them outside in another protected area such as an outbuilding.

If you are going to vacuum them up, be aware that ladybugs protect themselves when threatened by secreting a yellow fluid that is bad smelling and foul tasting. If they become alarmed, as they may be while being vacuumed up, the fluid may stain light coloured surfaces such as wallpaper or textiles.

Another removal method is to purchase or build a ladybug trap, though this may not be fast enough when there are hundreds of them milling about on your curtains. Pest control businesses sell ladybug traps but you can make your own and have it ready to go when the problem arises. Instructions can be found on the internet at:

Whatever method you use to remove the ladybugs, the pheromones that they release to attract others can linger inside your historic house and continue to attract other ladybugs. Cleaning may not be thorough enough to remove all traces of the pheromones, so sealing up the spaces around windows and doors, and the cracks in damaged siding is necessary to keep them from getting back inside.


The "ABC of Collections Care" (AMM publication) says to use nail polish when numbering artifacts, but other more recent sources state not to use nail polish as it contains cellulose nitrate. Is there an alternative to nail polish for labelling our artifacts?


The ABCs of Collections Care was published in the late 1980s and contains the best practices and knowledge of that period. At that time, it was standard practice to seal a spot on an inorganic artifact with clear nail polish, prior to and after numbering. Until recently, the Canadian Conservation Institute Note 1/5, Applying Registration Numbers to Paintings and Sculptures, included the use of clear nail polish to seal registration numbers on artifacts, though it was optional. (CCI removed Note 1/5 from its website last summer for updating.)

The problem is that clear nail polish is a commercial product designed for short-term use and most brands contain cellulose nitrate, an unstable substance. There are water-based nail polishes, and also solvent-based "natural" formulas, that contain acrylate copolymers. However, these cannot be recommended as the formulation of any commercial product can be changed by the manufacturer without notice, and a safe product can become unsafe without anyone being the wiser.

Fortunately, there are alternative products for adding a registration number directly to an artifact. A reversible synthetic varnish known as Paraloid B-72 can be used on unpainted non-porous surfaces (but not on plastics). An earlier formulation, Paraloid-67, is also available but it cannot be used on wax artifacts, and is also known to yellow with age.

As in all museum work, the standards for the application of numbers on artifacts must be met. Care must be taken not to apply these products to materials that are porous (such as non-fired ceramics and unfinished wood) where the lacquer will infuse and be difficult to remove.

Paraloid B-67 and Paraloid B-72 can be purchased in Canada from Carr McLean and Gaylord, in pellet form or liquid. The solid has to be dissolved in a solvent such as acetone. Due to their solvent content, they must be used with care, in a ventilated area. Ensure that staff and volunteers have read the MSDS sheet that accompanies each order.

The Northern States Conservation Center also sells a Collections Labeling Kit that contains a variety of products and tools for direct numbering and labelling, and instructions on how to use them. Their website has an excellent series of on-line articles that discuss the pros and cons of tags, labels and direct numbering. It includes a list of artifacts commonly found in museums, and how to label them.
Carr McLean also sells an Artifact ID Kit that includes a variety of labelling and numbering tools and supplies. (


We have several pieces of farm equipment in our collection, and the tires have become hard and flat on the bottom. Is there anything that can be done to restore them to working condition?



Until the 1930s, tractor wheels were usually made of lugged metal as solid rubber tires. They were fine on the road, but did not have enough traction to work in the field. Pneumatic tires were introduced in 1932 and were composed of an inner tube that contained compressed air and an outer protective casing that also provided traction. They proved superior to the metal wheels and by 1940 over 90% of new tractors were sold with rubber tires.

These early pneumatic tires were made from vulcanized rubber which is strong and flexible when new but liable to degrade over time. As time went by, the formulation and manufacturing process changed. Today, rubber tires are made with one of any number of synthetic rubbers, and contain curatives, adhesion promoters, anti-degradants and reinforcing chemicals that increase working life.

If older tires have not yet distorted and the equipment they are on is running, then regular use will help keep them from getting flat. Keep them clean but avoid commercial dressings which may contain undesirable additives intended for modern rubber. A mixture of paste wax and carbon black pigment can be used to protect the tires.

There is not much that can be done to restore older rubber tires to a “like new” condition as their degradation is due to a continuing chemical reaction that was originally responsible for curing the rubber. As the rubber molecules crosslink and shrink, cracking occurs. Reducing the temperature will slow down the rate of degradation, and this will occur seasonally if the tractor is kept outside. Keeping machinery in the shade during summer will provide a cooler temperature. Avoid light exposure as much as possible, as light accelerates decomposition of the rubber. Good ventilation will disperse any sulphur compounds that are off-gassed by the rubber.

When it is not in use, the tractor could be mounted on stands to keep weight off the tires and also off the axle. CCI Notes 15/2, Care of Machinery Artifacts Displayed or Stored Outside and 15/7 Rubber Components in Industrial Collections contain practical suggestions and includes a section on Protective Structures that discusses bases, blocking and covers. Mounting the tractor off the ground will also prevent the corrosion, mould and water damage that comes from contact with the soil. 


For many years, the museum community has been told about the importance of controlling temperature and humidity in their museums. We were told to try for a temperature of 21oC and 50% humidity. I’ve heard that’s changed. What temperature and humidity are we supposed to have?


Over the last few years, there has been a change in the way that temperature and relative humidity are addressed in heritage institutions. Instead of trying to reach what may be unrealistic setpoints of temperature and relative humidity, the current approach emphasizes stability of the environment over a specific setpoint. In other words, even a setpoint that is not in the ideal range is acceptable, providing it can be kept with a minimum of fluctuation.

The Canadian Conservation Institute has an excellent article ( that defines five levels of control according to a museum’s resources, collection needs and the type of building housing the collections:

Level AA - precision control, minimal seasonal changes to temperature only
Level A - good control, some gradients or seasonal changes, but not both
B - control, some gradients plus winter temperature setback
C - prevent all high risk extremes
D - prevent dampness

Although it is not possible to determine a museum’s level of control without environmental monitoring, most seasonal museums  would be Class C, which is defined as within 25–75% RH year-round, with temperature rarely over 30°C and usually below 25°C. This level is suggested by CCI as a target for open display collections in historic buildings where the building is as important as the collection.

According to information provided by CCI, this level of environmental control offers a high risk of mechanical damage to artefacts like musical instruments or veneered furniture; moderate risk to most paintings, most photographs, some artifacts, and some books; and tiny risk to many artifacts and most books. Although chemically unstable objects such as 20th century plastics and paper will become unusable within decades, the unheated winter conditions may retard the rate of deterioration considerably.

For museums in the C category, additional protection for special artifacts can be provided through use of cases, cabinets, use of packaging during storage. These buffer the artefacts against sudden changes in the environment which may cause mould, corrosion or desiccation.

Monitoring the environment in your museum will help you determine what the environmental conditions are so you can plan for improvement. Monitoring equipment is available free of charge from the Association of Manitoba Museums, through the Cultural Stewardship Program (CSP).


Our museum is an old two storey brick building that used to be a general store. It has two large windows composed of three tall panes, each side of the front door. We rotate displays of our collection in these windows about once a month. We have noticed that some of the clothing has faded from the sun.

These clothes are not necessarily in the window, but are on mannequins in the front of the museum. The windows have metal frames which frost up in the winter as we do not keep the heat turned up very high in the museum.

We spoke to a contractor about putting UV or solar film on the windows and he advised against it as he said he had several experiences where the outer window cracked when the inner window frosted up after putting film on them. We had a film on the windows we had in previously, but they had wooden frames and that did not happen to them.



There are really two questions here. The first is, why would the windows crack when film was applied to the inside? And secondly, what can be done to prevent collections being damaged by light coming in through windows?

Gordon Menzies, Building Technologist with Historic ResourcesBranch, explained that the metal frame in contact with the single pane of glass does not offer a “thermal break” to prevent heat loss. At cold winter temperatures, it is the slightly warmer air inside the building that touches the cold glass and condenses on the inside of the window that causes it to ice up and even crack.


The application of a UV-filtering to window glass is an effective method of reducing the damaging ultra-violet rays found in daylight, but it is not the only one, and is not necessarily the best choice for older, brittle glass. If you do not wish to adhere film directly to a window, Gordon suggests installing a piece of UV-filtering Plexiglas on the inside of the window frame, at least 6 inches from the actual glass and metal frame, held in place with a wooden rabbet. If UV-filtered Plexiglas is unavailable, purchase ordinary Plexiglas and apply UV-filtering film.


3M™ makes a Sun Control Window Film that removes up to 99% of UV rays. It can often be obtained through window blind suppliers, and automotive window-tinting companies. UV-filtered and regular Plexiglas can be obtained from suppliers of commercial plastics and often from picture framers.


Remember that it is not only the ultraviolet light that causes damage to organic artefacts. All light will cause irreversible damage over time. UV-filtering film will not reduce the amount of visible light – the brightness – entering the room.


High light levels can be prevented or reduced by using blinds or curtains to reduce the amount of light entering the room. And, by reducing visible light, you automatically reduce the UV levels.


During a recent regional meeting at the Commonwealth Air Training Plan Museum (Brandon), I had the opportunity to take light readings in front of three adjacent identical windows that were fitted with roller blinds and curtains. The first set of readings was taken with the blind up and curtains pulled back. Visible light was 330 Lux and the UV reading was 692 mw/lumen. Recommended levels for organic artifacts vary between 50 and 300 Lux, and UV levels should be less than 50 mw/lumen.


Readings were then taken in front of the second window with the blind pulled down. Visible light was 54 Lux and the UV reading was 33 mw/lumen. The last set of readings was taken in front of the third window, with the blind pulled down and the curtains closed. Visible light was 32 Lux and the UV reading was 0 mw/lumen.


In other words, just by using the type of window treatments common to historic homes, you can reduce the amount of light and UV to reasonable levels.


Please note that the amount of light recommended for the display of artifacts varies according to the nature of the artifact. Organic artifacts with coloured components (feathers, fabric, watercolours) are much more susceptible than metal or rock.


If you want to experiment with this yourselves, the Association of Manitoba Museums can lend you the equipment to take light readings in your museum as well as a complete list of recommended light levels for artifacts. The equipment is available free of charge to members, who pay only for the return shipping.


Please contact for more information.

The Association of Manitoba Museums acknowledges that we are on Treaty 1 territory and the land on which we gather is the traditional territory of Anishinaabe, Cree, Oji-Cree, Dakota, and Dene Peoples, and the homeland of the Métis Nation.