December 9, 2014
In June of 2014 we opened a time capsule that held three newspapers, two business cards and seven handwritten pages. These handwritten pages found in the Kings County Academy (Kentville, Nova Scotia) time capsule from 1929 have been transcribed by a volunteer at the museum. Most pages have faded or missing letters or words. In some cases these can be inferred via context but the transcription author acknowledges it does introduce the possibility of errors in transcription. As you will see he has marked in red those places where he had to make a judgement call on what was written. Sadly there are a few passages where it is unknown. On the other hand, this document is a priceless record of the state of the school district from 1888 until 1927 (earliest and latest dates mentioned).
The original author is unknown since it was not signed. But by not signing we can infer the intent was to give an overview rather than a personal account. Certainly, it does give an overview of the changes to the school including the names and terms of the Principals, changes to curriculum, classes offered, library initiatives, staffing changes and so on.
We are grateful for the considerable time and effort on the part of our transcriber who continues to selflessly devote many hours to all things historical. It is just such volunteers who are the mainstay of our community museum.
Previous posts related to the Time Capsule in this blog have had photographs of some of the handwritten pages which show the faded lettering and water staining. All of these entries and additional related information may yet become part of an exhibit on the history of education in Kings County.
I have attached a link to the transcription in PDF form below. Anyone who may have additional information on this important educational history can let us know at the museum. See our website Kings County Museum for contact details.
NOTE: the abbreviation ms in this document refers to the handwritten pages as manuscript.
KCA Time Capsule Handwriting Transcription
Documenting conservation work on objects in community museums in Nova Scotia CANADA.
Wednesday, 10 December 2014
Sunday, 24 August 2014
Teapot Repaired - Randall House Museum
August 19, 2014
I was asked to repair a broken teapot at Randall House museum after it had been broken in transit on a flight from Alberta. A set of china had been carefully wrapped in bubble wrap and placed in a hard shell carry-on bag but, sadly, the teapot split into two large pieces. The good news is that the break was relatively clean and given that they were larger pieces were easier to handle for repair.
I would recommend that china and other fragile artifacts be packaged in layers of foam and tightly secured in a hard shell case to avoid movement while being transported. Foam can be carved to the shape of the artifact both on a bottom and top layer which can then be wrapped to prevent movement.
Firstly, a general statement - conservators are not restorers. Restoring is a very specialized field requiring considerable training and experience. For example, ceramics restoration would require a solid grounding in chemistry to understand glazing, painting, firing, and general analysis of the many materials used in creating a ceramic piece. A restorer would fill cracks and do colour matching for the plain parts of the repair and the coloured parts. Their work can usually produce results that would be able to render the break (fracture) invisible to the naked eye. As you can imagine, this is a time consuming and expensive process and therefore is normally only undertaken where budget permits.
Secondly, conservators can do minor repairs such as putting this teapot back together without the crack filling and colour matching. Conservation work is normally done with the caveat that the repairs are reversible and at least visible under a microscope. These are ethical considerations in all conservation work.
Here is a photograph of the teapot prior to the repair work.
Tools and materials used in this repair....exacto-knife, wooden skewer (sanded to a fine point), small soft brush, and HMG B72 adhesive.
Here are the steps I took in the repair of the teapot....
With this repair done the teapot can be put in a display with proper lighting and placed in such a way that the break would be either not visible or essentially invisible. The break and repair along with this description now become part of the history of the artifact.
I was asked to repair a broken teapot at Randall House museum after it had been broken in transit on a flight from Alberta. A set of china had been carefully wrapped in bubble wrap and placed in a hard shell carry-on bag but, sadly, the teapot split into two large pieces. The good news is that the break was relatively clean and given that they were larger pieces were easier to handle for repair.
I would recommend that china and other fragile artifacts be packaged in layers of foam and tightly secured in a hard shell case to avoid movement while being transported. Foam can be carved to the shape of the artifact both on a bottom and top layer which can then be wrapped to prevent movement.
Firstly, a general statement - conservators are not restorers. Restoring is a very specialized field requiring considerable training and experience. For example, ceramics restoration would require a solid grounding in chemistry to understand glazing, painting, firing, and general analysis of the many materials used in creating a ceramic piece. A restorer would fill cracks and do colour matching for the plain parts of the repair and the coloured parts. Their work can usually produce results that would be able to render the break (fracture) invisible to the naked eye. As you can imagine, this is a time consuming and expensive process and therefore is normally only undertaken where budget permits.
Secondly, conservators can do minor repairs such as putting this teapot back together without the crack filling and colour matching. Conservation work is normally done with the caveat that the repairs are reversible and at least visible under a microscope. These are ethical considerations in all conservation work.
Here is a photograph of the teapot prior to the repair work.
Randall House Teapot - before repair |
Tools and materials used in this repair....exacto-knife, wooden skewer (sanded to a fine point), small soft brush, and HMG B72 adhesive.
Here are the steps I took in the repair of the teapot....
- photographs are taken before and after the work
- using a small, soft brush I carefully brushed along the break on both pieces over a sheet of paper to see if any smaller fragments came loose....none did....and to make sure no loose pieces would hamper fitting the larger pieces together,
- apply a minimum amount of conservation grade adhesive along the break,
- hold the pieces together for at least two minutes by hand in this case but larger clamps can be used in some cases. The adhesive used is flexible for two minutes and then hardens allowing for minor adjustments.
- carefully remove excess adhesive with an exacto-knife all along the join, inside and out. The knife is held at a very flat angle to just pick away without doing further damage.
- examine the join by moving the exacto-knife from side to side at various points along the break to determine the evenness of the join. If necessary, the join can be reversed and redone if not satisfactory. The adhesive used can be softened with a hairdryer at a low setting.
Here is a photograph of the teapot with the excess adhesive and a gap showing. The break did have a very few of the gaps and was otherwise a very clean break. The small and minimal bits of adhesive were carefully removed with the exacto-knife.
Randall House Teapot - before clean-up |
With this repair done the teapot can be put in a display with proper lighting and placed in such a way that the break would be either not visible or essentially invisible. The break and repair along with this description now become part of the history of the artifact.
Monday, 21 July 2014
Time Capsule Contents (Continued) - July 19, 2014
July 19, 2014
Handwritten Page 1 - enhanced |
Perhaps the most important artifact in the Time Capsule from June 19, 1929 is the seven handwritten pages discussing the Kings County school at the time. The title on the first page is Kentville Schools and there is no signature at the end which likely signifies it is a short history of the school rather than a personal account. From the first paragraph mentioning a report from 1888 it captures our attention considering it may hold information from that time until 1929. I have a photograph of the first page which will help to set the tone for future transcription and exhibit. Our intent is to show these pages sealed in mylar envelopes to prevent deterioration. Mylar is used because it is inert and has been proven to be safe for longer term storage and display. Mylar is one of several choices (polypropylene bags being another) in comic book storage particularly for Golden or Silver Age comics but also for any truly valuable comics. Either types of bags are clear so can be used for display purposes. However, polypropylene bags may yellow over a longer period of time so is not the best choice. Additionally, we can keep each page in the mylar envelope with an acid free backing board to ensure that it will not bend. It is best for these pages to be unfolded once only and stored flat which we have now done. Repeated unfolding may damage them. Think of them as fibrous material which may break from repeated bending. These pages are currently stored unfolded, flattened and in acid free folders pending purchase of mylar envelopes (on order). Displaying them in an exhibit in mylar envelopes can allow for viewing of the pages which will show the public the handwriting, fading, staining, etc. of the original. These are all important parts of the history of the artifact.
Handwritten Page 7 - enhanced |
Transcription of all seven pages will be done. As you can see by the photographs there is some fading along the right side and water damage in a few spots. This next photograph shows the last page which will be a challenge to transcribe due to more serious fading from water damage. However, with the use of image enhancement software we can attempt to bring out the more faded writing. You can also see that there is no signature at the bottom. This begs the question, who is the author?
Inks used in writing from the time period as with many other inks will fade over time. Direct sunlight is particularly damaging so these pages will be displayed and stored away in a carefully controlled low light setting for exhibit and stored in acid free boxes for longer term storage in a humidity and temperature controlled environment.
I mentioned in the last post that there are techniques to bring out faded writing. There are two worth mentioning: ultraviolet light (UV-A light or black light) and infrared light. Both are light at a longer wavelength and depending on the ink used each may work better. Since ultraviolet is the easiest and lower cost we would normally try it first. It is commonly used to authenticate oil paintings, antiques, and bank notes. Infrared light is more challenging because it uses more expensive equipment in a special setting. The phrase "infrared reflectography" is used for a technique that will show underlying layers in oil paintings such as drawings used as a guide by the artist. I mention these for use with the handwriting on the inside corner of the time capsule lid and possibly for some of the faded writing in the handwritten pages if it is necessary.
Conservation Tips:
Use mylar envelopes for storage of fragile paper, pamphlets, etc. You can purchase these in various sizes from comic book stores or on-line. Although more expensive than polypropyline it is well worth the extra expense. Measure your artifact first to determine the best size to use. Note: modern comics are smaller than 8.5 by 11 standard page size so be sure to order the correct size. Most comic stores (at least in my area) stock the modern comic size only.
Always keep fragile papers away from direct sunlight and strong lighting of any kind. Light is particularly damaging to inks and some papers. You can bring these artifacts out from time to time to look at them but minimize light exposure. In a museum environment lighting may be set to come on when someone enters a room to view them or limited to only a few hours of viewing.
Sunday, 13 July 2014
Time Capsule Contents - July 2, 2014
July 2, 2014
First thing was to take the capsule measurements:
Two weeks after the public opening of the time capsule I opened it again to start the conservation work necessary to record the objects as they are removed. This photograph shows the tools I will use (starting from the far right):
Getting Ready |
- an exacto-knife with a larger flat blade,
- a probe flat on one end, pointed on the other,
- a metal ruler for measurements, and
- a pen and paper to take notes.
First thing was to take the capsule measurements:
- 18.8 cm long, 11 cm wide, and 8.5 cm tall including the lid,
- 18.5 cm long, 10.5 cm wide, and 8.2 cm tall without the lid
The contents of the time capsule are (more details following):
- 7 handwritten sheets of paper
- 3 newspapers (details to come later)
- one small business card - Dominion Atlantic Railway
- one large business card - Town of Kentville
The capsule reacted strongly to a magnet implying that it has high iron content. The exterior and interior does show patches of reddish coloured corrosion which is another clue to iron content. The lid was made of a single flat piece of metal with notches in the four corners and folded over to produce an edge. One of the consequences of this is that there are minute openings in each corner which could allow moisture to enter the capsule. Moisture was evident on opening day on the paper observed.
Small business card |
Handwritten pages - pinned together |
The first thing I noticed upon opening the lid was that the handwritten sheets of paper folded on the top were now loose from the sides of the capsule. It is likely that it dried out to the point where it came loose. However, the newspaper below it was still attached to the sides. The folded up, handwritten pages came out easily with no tearing. On the other side a small business card in very bad shape was attached to the paper but came loose very easily. It is not easily readable but does have two lines printed in the lower left corner: Dominion Atlantic Railway and Engineer and Mechanical Supervisor. The person's name in larger lettering is printed in the middle. All is obscured by black spots and general deterioration. It is very fragile and requires special handling.
Carefully releasing edges |
Below this was a folded up newspaper with some parts attached to the sides of the capsule. I used an exacto-knife with a larger, flat blade to scrape along the sides to loosen the attached bits. This was done all around the sides. The newspaper came loose after a few minutes with minimal damage. This newspaper was dated April 18, 1929, two months before the capsule was placed.
Beneath this was another newspaper. I was able to loosen the newspaper using the exacto-knife. It was dated June 19, 1929. The date the capsule was placed.
What is in the bottom? |
Below this was a third newspaper and unlike the others this one had attached itself to some parts of the capsule beneath it causing slightly more tearing. This could not be loosened via an exacto-knife due to the location. However, it came out with only minimal damage. Some bits of newspaper are left intact in the bottom of the capsule along with a very well preserved business card for a Mr. Henry Morse Kentville Town Clerk and Treasurer. Although some small pieces of the newspapers were torn on removal all the text is readable except for the pieces shown at the bottom which will be left as is.
In my next blog entry I will show details of the handwritten pages. It is currently being transcribed by one of our museum volunteers. I will also write about the inscription on the inside corner of the lid. There are a few techniques that can be used with the right equipment to make the inscription clearer.
Sunday, 29 June 2014
Time Capsule Opened - June 19, 2014
June 27, 2014
The lid came open relatively easy with very little pressure applied. As shown in photograph "First view after opening", inside was found two distinct collection of papers: one a handwritten letter of several pages folded and stuffed on top; below it is a newspaper page. In both cases the papers show evidence of effects of moisture: both black and red spots as well as some other obvious water marks. In addition both of these papers are obviously "fused" to the sides of the capsule and the bottom newspaper could be "fused" to something unknown below it. The accompanying close-up photograph shows these in detail. How did this occur? It is quite possible that this is the result of repeated freezing and thawing cycles over 85 years. Condensation will form on the surface of metals below 10 degrees Celsius. The fusing presents a significant problem to their removal. There is the possibility that the two documents could be fused together which means they could tear apart and destroy some of the writing if removed separately. With some parts fused to the side it introduces more chances of tearing. Another photograph (see lid inscription below) shows evidence of tearing in the corner of the handwritten page. It is likely this occurred when the lid was removed.
The inside of the lid shows bits of paper and an inscription initially transcribed as:
Ben (or is it Eric?) Schofield
Rockwell Mtn
June 19/29
On the left, centre in the photograph is a fragment of the handwritten paper torn from the pages. This occurred when the lid was pulled off.
85 year old time capsule |
On June 19, 2014 at the Kings County Museum in Kentville, Nova Scotia I had the opportunity to open a time capsule 85 years to the day when it was deposited in 1929. The capsule as shown in the photograph consists of a metal box approximately 10 cm wide, 10 cm high, and 25 cm long (exact measurements will be posted at a later date). It was deposited in a granite block with a carved out space specifically made for it. The capsule was one of two found on the site of the Kings County Academy, a decommissioned school demolished recently in Kentville, Nova Scotia. It has corrosion on the outside and what appears to be patches of cement throughout the exterior. The corners of the lid show gaps which introduced the possibility of moisture getting inside. The other time capsule found onsite in fact was opened by demolition staff and was a mass of muddy brown watery material. It has not been processed to see if anything solid is inside but will be at a later date.
First view after opening |
I will explain the best approach in conservation of this historically precious artifact and its contents. Keep in mind that the museum has a mandate to preserve and protect the cultural history of Kings County which means we must take the safest approach in examining, evaluating, documenting and exhibiting historical artifacts. Most activities of this nature would be done in a laboratory setting where environmental conditions can be carefully controlled. These photographs show the artifact outside of the sealed plastic envelope it was stored in. It is kept in a humidity and temperature controlled and secure area until worked on and returned to it when done. It is critical to maintain moisture levels at a steady state to ensure the artifact and its contents do not dry out or become moist in high or low humidity levels too rapidly. This latter condition can rapidly deteriorate some artifacts.
Documents close-up - water marks |
Paper tearing from lid removal |
The lid came open relatively easy with very little pressure applied. As shown in photograph "First view after opening", inside was found two distinct collection of papers: one a handwritten letter of several pages folded and stuffed on top; below it is a newspaper page. In both cases the papers show evidence of effects of moisture: both black and red spots as well as some other obvious water marks. In addition both of these papers are obviously "fused" to the sides of the capsule and the bottom newspaper could be "fused" to something unknown below it. The accompanying close-up photograph shows these in detail. How did this occur? It is quite possible that this is the result of repeated freezing and thawing cycles over 85 years. Condensation will form on the surface of metals below 10 degrees Celsius. The fusing presents a significant problem to their removal. There is the possibility that the two documents could be fused together which means they could tear apart and destroy some of the writing if removed separately. With some parts fused to the side it introduces more chances of tearing. Another photograph (see lid inscription below) shows evidence of tearing in the corner of the handwritten page. It is likely this occurred when the lid was removed.
The best approach is to use a tool which is flat and narrow with a sharp edge to carefully break apart the papers fused to the sides and then carefully try to remove the papers as a package. The other option might have been to apply a small amount of steam to the edges which might facilitate releasing them from the sides. There are steam tools that can be used with a wand to pinpoint accuracy. However, this is not a good choice in this case since the handwritten sheets are already showing evidence of moisture damage. Where documents are "water fast" this would be a viable option.
Interior lid inscription |
Ben (or is it Eric?) Schofield
Rockwell Mtn
June 19/29
On the left, centre in the photograph is a fragment of the handwritten paper torn from the pages. This occurred when the lid was pulled off.
I will be doing further work on the capsule over the next few weeks and will post the results over time. In all cases the contents and the capsule will be carefully measured, the handwritten letter transcribed, everything photographed and catalogued. It is anticipated that an exhibit will be put together to show the results to the public at a later date.
Saturday, 19 April 2014
Silver Artifacts Conservation - April 17, 2014
April 17, 2014
Small trophy - full view - before |
Tarnish is formed on the surface of silver when it is subject to high humidity, moisture or air pollution. The silver combines with sulphur in the air or moisture to form silver sulfide (AgS) which is black in colour. Removing this black material is usually done by polishing with a soft cloth. Silver is easily scratched when polished. In fact, no matter what you use to polish it there will be minute bits of silver worn away each time you polish often only visible by using a microscope. Over time this will become a critical issue with silver laminates since the silver itself can be worn down to the base metal. Not only do the scratches become unsightly but then you may have the brass colour showing through in some other parts of the artifact. Often the base metal is a copper alloy such as brass but can be many other types of metal. This photograph shows a trophy with a black sheen of tarnish, silver laminate on a copper alloy base, dust on the wooden base, and a strip of scotch tape. The tape was loosely attached at the top back edge (reason unknown).
Small trophy - close-up - before |
Conservation of silver involves several steps but the intent is to avoid or at least minimize scratching the surface. This is accomplished by using the softest materials readily available and a few simple techniques. There are many commercial silver polishes available that are widely used and certainly perform the polishing quite readily. However, what many conservators use is precipitated calcium carbonate which is a more pure form of chalk that is very gentle in the polishing process. This material can be purchased relatively cheaply at most pharmacies. You need very little every time perhaps only a tablespoon which you mix with distilled water to make a paste. So the combination of the chalk with no impurities and a pure form of water will combine to make a polishing substance with very limited chance of scratching.
Small trophy - close-up - after |
Small trophy - full view - after |
Always use nitrile gloves to handle the silver to reduce contact with the oils, salts, and ammonia found on skin. With every artifact the first step is to gently wipe the surface with a soft cloth to remove dust or any other grainy substances that may be present. Moistening the cloth with distilled water may be done as well. The polishing paste is then applied to the silver artifact with a soft cloth. I apply it gently in a circular motion over the area to be polished. I usually do this twice and find that in most cases there is still a bit more tarnish removed a second time. The polishing process is finished by a gentle wiping with a clean soft cloth. Again, the cloth can be moistened with distilled water.
Lastly, the best way to store silver is wrapped in acid free paper within a tightly sealed polyethylene bag and at a relative humidity of 40% or less. There are some conservation grade treatments that can be applied as a layer to the surface. Also, there are anti-tarnish strips that can be stored in the bag with the artifact wrapped in the acid-free paper so it does not come in contact with the strips.
These photographs are of a trophy that was conserved in this manner. This trophy dates from 1950 and was awarded during the Apple Blossom Festival in Kentville Nova Scotia Canada.
Sunday, 9 February 2014
Prescott House Metal Objects - February 9, 2014
February 9, 2014
In a previous post I showed how I re-assembed a glass bottle that was found in pieces at an archaeological dig at Prescott House, near Wolfville, Nova Scotia. The first photograph here shows us working on the dig. We were in a class at Acadia University learning about archaeology and history in the area. The three of us on the left are working in an area that appeared to be part of the wall or foundation of a building. The original house from the early 1800's can be seen in the background at top right. Behind us is a road to a grounds keeper's shed.
The bone handled knife was the best example of the stresses of moisture. It was moist when it was removed from the soil and rapidly dried out. One part of the bone handle came loose within minutes. I suspect the moisture was holding it together. This is repairable with the same adhesive used to reassemble the bottle in my previous post, Acryloid B72 restoration adhesive. The blade of the knife was obviously broken at the end with a jagged edge. There is an obvious pattern to the material showing as a layer over much of the blade. I suspect that this was the sheath in which the blade was kept. Very little cleaning was done on the blade to preserve this material for possible future testing. All loose material was carefully brushed off and the wax applied overall as a preventive measure. The wax had the added benefit of sealing up many small fractures in the bone and making them much less visible
The button shown here proved to be one of the more interesting objects to work on because after cleaning and treatment a very clear pattern became visible on the back. It is characteristic of fibres in cloth suggesting that this is either the remnants of the material the button was sewn onto or a piece of cloth it was laying next to while in the ground. I did very little cleaning of this side - using only a very fine, soft brush to ensure that none of this material would be removed. It is possible that in the future someone may wish to have the material removed and examined so preserving it was my priority. The front had a pattern of two small circles and bumps but was very obscured due to corrosion. The condition was such that we cannot identify a date or its usage. Once again, a fine layer of museum grade wax was applied to seal it from further moisture damage.
In all cases these metal objects were accompanied with a two page laboratory record document that provides a detailed description, measurements, structure, possible history, manufacture, treatment applied, before and after photographs, storage and exhibit environmental control suggestions, and any other additional notes that were relevant. These documents becomes part of the permanent record for the province of Nova Scotia and Prescott House the owners of these important objects.
Prescott Hose - Archaeological dig, Fall 2013 |
I was given the opportunity to work on four metal objects that were found at the same location. These are a belt buckle, ice creeper (not discussed here), button, and bone handled knife. Each of these came to me in a plastic bag labelled with the location in which it was found and still immersed in the original soil in which it was found. This is the best way of removing these from their original location because it allows me to assess the impact of separating them from their environment and perhaps, if budgeting permitted, to get the soil analyzed. For precious objects this would be a necessary exercise to determine the best route of treatment. The constituents of the soil would help make the decision on which chemicals to use for cleaning, preventive measures, and storage. Since, in this case, we are dealing with a limited budget and non-precious objects (objects of lower value) this was not done. However, it does not stop us from doing some basic conservation work on these interesting objects.
I have provided photographs of three of these showing before images in which you can see the results of cleaning. There are
several important lessons to be learned from this work. All these had a
very serious amount of corrosion products in an active state. This was
the result of many years where they were immersed in soil and sand
subject to rain and snow with alternating freezing and thawing
conditions typical of Nova Scotia. All of which exert considerable
stresses.
|
Bone-handled Knife |
Buckle - front - before cleaning |
Buckle - Front - Finished |
The buckle shown here was a mass of corrosion, sand, soil, and plant root. The layers of corrosion were heavy enough that it could not be completely cleaned off. No parts of it was movable and the underlying metal is not visible at all. Once again, any loose material was carefully removed and a layer of wax was applied. This object reacts strongly to a magnet so is likely made of iron.
Button - Back - Finished |
Button - Back - Cleaned |
In all cases these metal objects were accompanied with a two page laboratory record document that provides a detailed description, measurements, structure, possible history, manufacture, treatment applied, before and after photographs, storage and exhibit environmental control suggestions, and any other additional notes that were relevant. These documents becomes part of the permanent record for the province of Nova Scotia and Prescott House the owners of these important objects.
Tuesday, 21 January 2014
Environmental Considerations For Mixed Collections of Historical Artifacts - 2014
January 21, 2014
Basic Environmental Factors and Recommended Levels
This document is a general discussion and overview of environmental factors. Please refer to the references below for more detailed information.
The following discussion
focuses on artifacts that are comprised of metals, glass, ceramics, papers,
textiles, organics or in-organics all kept in the same space. This document outlines the environmental considerations
and conditions for their storage and display in general terms for community
museums. I have provided several
references at the end for further detailed information specific to each type of
material.
Many historical artifacts are made up of several different materials attached and combined in various ways and would benefit from careful environmental considerations. Temperature and moisture fluctuations put undue pressure on their structure and in some extreme conditions can cause fractures. Different metals expand and contract with temperature changes to different degrees. This is also true for different woods which will have different moisture content as well. Particularly fragile are some older papers, wood, and porous ceramics that are hygroscopic – meaning they can absorb and give off moisture. Higher and lower moisture levels can be particularly damaging to their cell structure. Condensation can appear in some metals at temperatures below 10 degrees Celsius. This promotes corrosion and can negatively affect other materials when they are stored in close proximity. Storage materials can also play a role in deterioration since we know that materials such as some plastics can give off gases and over a lengthier period of time when combined with moisture form a mild acid. Glass is more stable as is acid free wrapping paper, storage boxes and envelopes.
Some general information for artifacts kept in a community museum environment follows where it is assumed that special air conditioning or lighting controls are not available for storage or display of these artifacts. This is true for most community museums in Nova Scotia, Canada and in general terms, elsewhere. However, Nova Scotia is subject to a climate similar to United Kingdom in that we have on average 85% relative humidity over the course of a typical year but colder weather (and snow!) in a slightly longer winter. The freeze and thaw cycle over the winter months is particularly challenging when some museums shut off the heating systems or set the thermostat too low while the museum is closed. This is also a concern for those who have historical artifacts in their homes and leave for a few months with the thermostat turned down and the humidifier turned off while vacationing where it is warmer.
In all cases it is best to keep things in a steady state. That is, to avoid rapid fluctuations in humidity, temperature, light levels and so on. Even moderate fluctuations are to be avoided but are not as damaging. Where possible, monitor the temperature and humidity as a minimum watching for wild changes over a short time. There is relatively inexpensive equipment available to do this but it requires effort on someone’s part to check the results. If you must turn the temperature down or bring the relative humidity up or down (for example, when doing building repairs) do it over a longer period of time and return it back to normal settings over a longer period of time. This allows the artifacts to slowly adjust without cracking, getting condensation, and so on.
Dust levels and vibrations are also a consideration if work is being done nearby or in your building. Recently we became concerned at a community museum when roadwork outside caused serious vibrations inside our building when heavy machinery was working on the street outside our door. We packed some things away to ensure they did not suffer damage from dust, falling over or off shelves.
Many historical artifacts are made up of several different materials attached and combined in various ways and would benefit from careful environmental considerations. Temperature and moisture fluctuations put undue pressure on their structure and in some extreme conditions can cause fractures. Different metals expand and contract with temperature changes to different degrees. This is also true for different woods which will have different moisture content as well. Particularly fragile are some older papers, wood, and porous ceramics that are hygroscopic – meaning they can absorb and give off moisture. Higher and lower moisture levels can be particularly damaging to their cell structure. Condensation can appear in some metals at temperatures below 10 degrees Celsius. This promotes corrosion and can negatively affect other materials when they are stored in close proximity. Storage materials can also play a role in deterioration since we know that materials such as some plastics can give off gases and over a lengthier period of time when combined with moisture form a mild acid. Glass is more stable as is acid free wrapping paper, storage boxes and envelopes.
Some general information for artifacts kept in a community museum environment follows where it is assumed that special air conditioning or lighting controls are not available for storage or display of these artifacts. This is true for most community museums in Nova Scotia, Canada and in general terms, elsewhere. However, Nova Scotia is subject to a climate similar to United Kingdom in that we have on average 85% relative humidity over the course of a typical year but colder weather (and snow!) in a slightly longer winter. The freeze and thaw cycle over the winter months is particularly challenging when some museums shut off the heating systems or set the thermostat too low while the museum is closed. This is also a concern for those who have historical artifacts in their homes and leave for a few months with the thermostat turned down and the humidifier turned off while vacationing where it is warmer.
In all cases it is best to keep things in a steady state. That is, to avoid rapid fluctuations in humidity, temperature, light levels and so on. Even moderate fluctuations are to be avoided but are not as damaging. Where possible, monitor the temperature and humidity as a minimum watching for wild changes over a short time. There is relatively inexpensive equipment available to do this but it requires effort on someone’s part to check the results. If you must turn the temperature down or bring the relative humidity up or down (for example, when doing building repairs) do it over a longer period of time and return it back to normal settings over a longer period of time. This allows the artifacts to slowly adjust without cracking, getting condensation, and so on.
Dust levels and vibrations are also a consideration if work is being done nearby or in your building. Recently we became concerned at a community museum when roadwork outside caused serious vibrations inside our building when heavy machinery was working on the street outside our door. We packed some things away to ensure they did not suffer damage from dust, falling over or off shelves.
Basic Environmental Factors and Recommended Levels
Relative humidity, the recommended acceptable level day
and night throughout the year is 50
or 55% +/- 5% with the acceptable
range of 45 to 60% for mixed collections.
Light exposure,
recommended generally acceptable
level is 100 lux (lumens per metre squared), high levels of lux
exposure are not usually harmful to metals, glass or ceramics but are
detrimental to coloured objects since it can result in fading of colours; levels above 300 lux can cause eye
adaptation difficulties for visitors in some facilities. Light
exposure can be measured with a light metre as used by photographers.
UV radiation, the
general recommended level of Ultra
Violet exposure is 75µw/l (microwatts per lumen). Extended
exposure to sunlight is the most damaging although quartz halogen lamps are
also a concern. Do not hang or
store any painted artifact in an area that is subject to direct sunlight.
UV can be measured with broadband UV sensors, for example, which is specialized
equipment usually outside the budget of most community museums. Just
ensure that all painted or coloured artifacts (examples: samplers, paintings,
prints, papers, most textiles) are kept out of direct sunlight.
Temperature, the
general acceptable level in winter is
19 C +/- 1 C and 24 C +/- 1 C in summer with a minimum temperature of
10C at any time to avoid condensation particularly in metals.
References
This document is a general discussion and overview of environmental factors. Please refer to the references below for more detailed information.
1) This is an excellent overview of general
preservation guidelines and recommendations for mixed collections thanks to the
Minnesota Historical Society:
2) Canadian Museum of Nature – Collection
Conservation:
3) Environmental Guidelines for Museums by the
Canadian Conservation Institute:
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