In a presentation related to the Disaster theme of the conference, speakers Colford and Christie spoke of the recovery of flood damaged photographic collections of the Peterboro Municipal Archives, in Ontario in 2004. The area wide disaster created such demands on affected infrastructure that the response began two weeks after the peak flood, which led to a decision to freeze all the of works, including glass plates and film negatives as other methods of drying had not been possible. The PMA participated in a CCI risk assessment which reported back with recommendations to keep all film stabilized in freezers for continued cold storage, and to identify cellulose acetate negatives as a specific priority for treatment due to their autocatalytic behavior, leading to eventual change and loss of values.
The authors, looking to Pavelka & Naipavel-Heidushke’s paper on successful treatment and separation of gelatin image layer from acetate support, called out Pavelka’s suggestion that insurance companies might provide financial assistance for treatment in their coverage. Following the protocol suggested in the article, the authors proceeded and achieved inconsistent results. They noted the process per negative could take up to ninety minutes, resulting in only four negatives treated over two days, They cited concerns of prolonged exposure of the negative to solvents, yet found it hard to keep solvent from evaporating, which could induce curl and tensions while drying. A new question developed, what was the difference between the article’s case studies vs. theirs? An obvious variable was the fact that these items had been frozen. Whether or not this actually factored into the negatives’ behavior. Consulting further with Greg Hill (currently of the Canadian Conservation Institute) & Gayle McIntyre (Sir Sandford Fleming College), the protocol was revised to include the following steps, which helped increase the reliability of the method across different negatives:
1. Remove material by cutting away some of the lip/edge of the negative to allow ingress of solvent
2. Prewet the negative using sequential solvents
3. Use visual and tactile clues to determine the moment of separation (need slide 3.1, 3.2.) not a fixed amount of time
4. If the gelatin is still disrupted, reshape while it is still wetted using gentle prodding (with brushes on silicon release Mylar*) to lay flat before drying completely. The unsupported pellicle, thin as tissue, can be left to release final residues of solvent in a non-stick drying pack in fume hood to offgas.
(More images of these steps available in the downloadable Kiss Your Acetate Goodbye images of layer separation, pdf file kindly provided by the speakers.)
The images, now supported on Mylar sheets, were digitized, and the storage solution after treatment includes use of polypropylene sleeves in a clamshell binder. In an added benefit, the items are no longer taking up space in cold storage. The authors report that after eight years, the images appear unchanged in these conditions. While having a positive outcome, the speakers note that is still a lengthy process involving time and material costs, requiring trained professionals. This technique may not be a catchall for all collections, but for prioritized ones, it can be effective management tool for severely decaying negatives.
*Additional note: Silicon tip tools may also be useful here. See related content from 2016 BPG Tips Session on Silicon Shapers, as found in art supply stores today among the brush selections for working thick paints, in the BPG wiki.
Author: NoraLockshin
44th Annual Meeting – May 15th – (Textiles session) Dark Side of the Force: Magnets, Velcro & Unintended Consequences – Maureen Merrigan and John D. Childs
A site-specific artwork to span the distance of a corridor which joins the two central thematic halls was commissioned for the National September 11 Memorial and Museum, which was awarded to Spencer Finch for his proposal,“Trying to Remember the Color of the Sky on That September Morning”. The museum’s exhibition staff worked with the artist to design a suitable mounting understructure, which only revealed problems within days of the official opening.
The underlying structure proposed by the exhibition staff was to mount the 2,983 pieces of heavy watercolor paper that make up the composition onto a steel mesh grid using bulldog clips. However, the artist’s desire was for the watercolors to appear to float, with a varied distribution – the clips restricted positioning to a linear grid, so the team worked to create a more randomly positionable mounting strip using earth magnets, contained in small coin enclosures affixed to the back of each component piece.
The work had to be installed during construction phase, and so when completed, the team wrapped it entirely in polyethylene sheeting. Despite these precautions, when checked prior to opening day, it was noted that a circular pattern of dirt, focused around the underlying magnets, had appeared upon pieces of the art work, which would be come to be called the “owl eyes” phenomenon.
For a quick fix, the visible dust was lifted in-situ with low-tack masking tape, but the team kept watch and eight weeks after opening, they repeated the cleaning upwards to a distance of eight feet from the floor level, based upon the ladder height. Due to high profile and high numbers, all exhibit maintenance has to be done after hours, and the work cannot be blocked from use or view, so scheduling and moving the scissor lift was prohibitive.
Knowing that repeated intensive cleanings were not a solution for an installation expected to last five years (and likely longer), the team considered a new mounting protocol for reinstallation that would reduce the attractive force of the magnets to atmospheric dust. The first intervention mocked up placed greater distance between the primary support and the magnet by embedding the mounting magnet into Velcro attached to the emptied magnet pocket but it was ultimately unsuccessful due to differential relative humidity causing curl of the papers away from the pressure sensitive adhesive on the back of the hook tape attached to the envelopes; the hook portion remaining attached to the loop up on the grid.
The dust/dirt were tested by both air sampling and particulate identification. The museum has a regular health and safety sampling protocol due to a high level of nuisance dusts from entries, and potential of asbestos release from the collections themselves. Interestingly, no iron was detected in the air sample, potentially because the deposition settles at a rate too slow or is too diluted over a volume for an eight hour test. Conversely, particle identification showed that seventy-five percent of the dust were definitively iron particles. Environmental sources for airborne iron in cities such as include vehicular traffic exhaust, brake dust, incinerators and more. (An aerial view of the site was provided to show adjacent high-contaminant zones, and sources of pollution near the intake vents.) Although the intake air for the museum is filtered, there are many sources of these at the densely settled and circulated location at the tip of Manhattan that can also enter via the access doors, loading dock, and on dust carried by visitors and staff. The thought that dust was one-time construction related was disproved, from having noted that other objects in cases that mounted with magnets around the same time do not have the same problem.
Therefore, with cooperation from the artist, elimination of the magnets was decided to be the best solution. In the full intervention, the team sliced away the leading side of the coin pockets, removed the magnet, and placed the pressure sensitive adhesive Velcro onto the remnant pocket, a total of 11,932 instances, which was performed in overnight shifts over four weeks. Unfortunately, within a few weeks, this was shown to be ultimately unsuccessful due to differential heating and cooling of the front of the artwork causing curl and failure of the pressure sensitive adhesive (from which to which?). A new round of testing was undertaken, with a goal to maintain the artist’s careful non-linear placement, by continuing to depend on the hook and loop attached to the wall mesh. The primary supports were carefully adhered overall to a mat board, which would be pressed to the receiving tape, now stapled through the mount support.
These test mounts using extra paintings supplied by the artist, were installed between the upper two air vents for an observation period. When the new method proved successful, 150 facsimile prints made from digital captures of the artwork components were created as placeholders while the artwork components were switched out overnight for remounting, so as to avoid interruption for the visitors, numbering in the thousands daily, and include in rapid succession heads of state, such as the Presidents of the United States, the Duke and Duchess of Cambridge, and the Pope.
The question and answer period was lively with the following exchanges:
Q: if dust is still in the air, is that not a problem elsewhere for unglazed works such as paintings?
A: Yes, dust has been noticed also on vertical surfaces, and so there is a regular housekeeping program to clean these
Q: How do you protect against fading for this long exhibition?
A: In discussions with the artist, he selected Winsor & Newton colors with the highest lightfastness ratings, plus created digital captures. If fading becomes noticeable, they will be replaced with digital facsimiles, and there is a record copy of the artworks to compare against for the long term 5 year timeline, but that could be extended.
Q: [Gwen Spicer, conservator and author of a forthcoming book on magnets in conservation commented:] Noting that aerosols of particulates can be up to 10-20% in cities’ air [for more info on particulate matter and Air Quality Index, see data from the Environmental Protection Agency]. The particle size is critical to the attractive force – and in lower Manhattan with it many towers, you have a canyon effect for intake of highly concentrated flows of fine iron oxide particulates. This is a real health issue – and research is ongoing into low tech ways of finding and binding pollutants. In Oregon, tree moss is being used as a particle sink to identify pollutant sources. Also, it is now common for computers to have magnetic shielding/filtering to protect electromagnetic media, but not buildings. [In a suggested technology transfer, she noted] Could RFID blocking scrim be repurposed to protect indoor air?
Q: Why was choice made to use Lascaux in uncontrolled environment, versus paste & paper? Why were the artworks mounted to another hygroscopic board overall versus an inert support – was there a weight issue?
A: The choice was due to the need to turnaround multiple objects in limited space and time, without ability to lay out and weight a water based adhesive with a water soluble artwork. A paper support was preferred to reduce the differentiation in dimensional change or moisture uptake between the artwork and the support.
Q: Was actual Velcro(TM) used or generic hook and loop tape?
A: “We used generic hook and loop tape from Eastex Products. They were able to provide the custom sized pieces in the timeline we needed.”
43rd Annual Meeting, May 15, 2015, “The How and Why of Reusing Earth Magnets”, with Gwen Spicer
As we approach another conference in which Gwen Spicer will share her vast knowledge in the workshop sessions Ferrous Attractions, the Science Behind the Magic (spots available as of this writing), we call attention to her 2015 session in which she explained attention that can be paid as to the sustainability of their use. This content has also been submitted to The Book and Paper Group Annual 34, but for those who are not BPG subscribers, is available on her website: The How and Why of Reusing Earth Magnets.
First she addressed what exactly are the “rare earths” from which these strong magnets are made. Chiefly, they appear among the lanthanide series of elements from the lower part of the periodic table – elements 57 through 71 and a few more. They are called rare because although they are naturally found intermingled, early on in industrial mining history, they were hard to separate due to their chemical similarities. (More information including a timeline of refining and increased production may be found on Spicer’s website and blog.)
Addressing the primary theme of the conference, Spicer asked “is it sustainable or not to use these elements, and if so, why?” Today, advanced industrial processes have made these rare earth elements easier and cheaper to separate, leading to their relative ubiquity, to a point that they are now are considered disposable. You may be surprised to learn that they make up components in so-called green technologies, such as hybrid cars and wind turbines. Because they make rapid electrical transmission in miniaturized components possible, they are one of the things that make inexpensive portable electronics possible, such as small appliances, earphone/buds, and mobile phones. While recycling/e-cycling the more expensive products such as phones is becoming more common and a cash value is placed on turn-in programs, those smaller items represent a non-recoverable portion of an ultimately finite resource.
To refine these rare earth elements, because they appear “rarely”, mining companies actually have to go through a very large amount of product to recover a small amount of valuable stock, resulting in industrial waste. As with any mining process, there are sad truths of waste management, such as polluted tailing ponds, release of atmospheric dusts, and junk metals discarded, all of which are potential contributors toward environmental pollution.
While there was production in the US, a highly visible mine incident in Mountain Pass, CA, led to closure based on EPA citations. Not surprisingly, much of the world’s production (95%) comes from China, where environmental standards are considerably more lax. To make the most profit, some countries will also offshore the labor intensive refining and processing of ore to poorer countries, leading to other uglier truths, such as the protection of the worker and environment coming down to an economic compromise, or conflict. Population studies in some countries show higher incidence of higher cancer rates and shorter life span for workers in these industries.
Spicer reported that economic and political tensions has caused Japan to invest in production of more efficient technologies and reexamining of older technologies, so as to use less material overall. As the trend shifts from the cheapening of the source material to what may eventually become more costly due to the consumer waste and reduced availability. (For further reading, Spicer goes into more detail on geo-economic and political tensions in the BPG article linked above.)
On a more positive note, Spicer turned back to what the conservator interested in using earth magnets can do; first she advises becoming a wiser and more informed consumer and user. (Just reading this article is a start!) Proper care and handling of earth magnets, chiefly the Niobium-Ferric-Bromide type, can reduce one’s overall impact by conserving the intensive material resources needed to make them. There is an excellent table of information in the article; as example, tips drawn from this session discussion include:
⁃ Earth magnets have sensitivities: protect them from extremes of heat, mechanical shock, moisture.
⁃ Use appropriate techniques to adhere or countersink them into substrates. For instance, use of hot melt glue can deactivate a magnet.
⁃ To ensure longevity during storage and use, separators are key, such as foam padding, or sinking them into other materials such as corrugated boards or foam.
⁃ Use smaller containers such as the ones they are shipped in, or pill separators, to keep them from banging into each other or ferromagnetic surfaces. Recycle other small containers, such as contact lens cases, to increase separation in small cubic space.
⁃ Keep like materials together and unlike apart – niobium apart from ferromagnetic surfaces to avoid demagnetization.
⁃ See further references in Spicer’s bibliography.
Lastly, as a watchword, Spicer leaves us with the mantra “let us be aware of best environmental practices just as we do in other areas of treatment…”
In the Q&A period, the following discussions arose:
Q: About suppliers: do any companies have more sustainable practices than others?
A: There are kind of two categories – some companies are affiliated with the mining sources, converting earths to magnets; and then there are those that just sell them. For instance, the Mountain Pass mine has started up again in US, under new restrictions, using previously gathered raw material to produce new product
Q: Are there any insights into how to dispose of or recycle earth magnets?
A: There are at least 12,000 e-cycling programs across the U.S., definitely contact them! Recycling can also a present a conflict for resources as trash picking and separation is an economic way of life for some. But for broken ones, sharp or deactivated, recycling companies are a good option to divert the unusable portion versus the municipal waste stream. Harvard University Libraries suggests contacting Terracycle of NJ, to take away waste stream that is disallowed from municipal collections.
Q: At a recent symposium, the personal safety issue came up. What are current safety recommendations for bulk storage of magnets or use for persons with pacemakers or other electronic medical devices?
A: From discussions Spicer has had, generally a magnet force field limited to three inches from the pacemaker (or other medical appliance), can be a distance of concern – this could take even place where dangling earbuds with embedded magnets are present (see the tiny print warning label on packaging of these). It is important to note that the force of the magnet is a factor of its size and any shielding around it or the object it may be attracted towards. Generally an artifact in exhibition which is mounted with magnets is very far from that distance, but it could be true for workers in a lab, or someone carrying an object enclosure with an embedded magnet.
Use of signage on enclosures or mounts indicate presence of covered magnets is a good common sense warning. As magnets are brittle, and can fly across a table at each other at great speed and shatter, safety goggles are highly recommended at all times. Hand protection may also be necessary for the worker, as pinching, splinters or nail breakage, can all be issues when separating magnets, or prying them out for reuse. If you maintain a private practice with a studio in your home, or have occasional younger visitors to your lab, be aware that swallowing by children or animals is an issue! See the U.S. Consumer Product Safety Commission warning that was issued for more information on magnet dangers for small children. (This author is currently working on a Job Hazard Analysis for work with magnets with the assistance of an industrial hygiene group; potentially this may become available through AIC Health & Safety group as well.)
43rd Annual Meeting – Book and Paper Group Session, May 16, 2015. “Affichomanie: Retracing the History and Practice of Lining Belle Epoque Posters with Fabric” by Tessa Thomas
Seeing a nice grouping by the BPG program organizers of talks about big paper, I settled in to be enchanted by more pretty pictures in the second talk of the day. The work originates in the gift to Art Gallery of Ontario of well-known and more obscure works (ephemera, Christmas cards, postcard doodles, & sketches, & theater programs) from the golden age of chromolithograph poster art – some of which drew myself and others to the practice of art entirely. Thomas was a recipient of a Kress fellowship to undertake a study of the collection and has written for the museum’s blog on some of her findings.
Thomas gave a brief but thorough background on the art and cultural historical context of the rise of the poster as art, starting with the law of 1881 which allowed for the liberal posting of posters (except where noted by stenciled announcement) in contrast to when prior authorization was always required by the government. This was not exclusive to advertising posters, but an act for freedom of the press and public commentary, from which artists and culture benefitted equally. This created a mass media culture, where the newest poster was eagerly awaited by a public hungry for visual beauty and information in an otherwise grey city, giving rise to competing trends and spurring innovation in graphic communication. These were also the new publicity machine for the theatres, and advertising the artists – performing and visual. Thomas illustrated this with beautiful vintage contemporary photographs and illustrations highlighting the streets and walls of Paris – showing posters in the environment, giving “color and energy to the dim hustle of Paris”. Details in these images speak to features found on posters that were mounted, such as tax stamps, original folds, as opposed to ones printed and unused, or saved for later use or resale.
It is an oft repeated tale that at the peak of “poster mania”, fans would steal the freshly pasted posters. Did an 1893 article published by Felix Phénéon, art critic and anarchist,incite, or describe current goings-on, suggesting that fans of the poster steal them fresh off the walls. Singling out Henri de Toulouse-Lautrec’s, “these posters are really fine, …steal them, wash them, hang them in yr apartment … where of course your landlord lets the wallpaper hang in ribbons.” Thomas was curious to find evidence in the AGO collection that might support this possibly apocryphal legend. She considers it more likely the affichiomanistes rather paid off the poster pasters, and this story was a red herring to throw off the sponsor of the posters as to why so many went missing! Popularity indeed created the poster art gallery system, and Thomas sought out the archives of Sagot et Cie, one of the oldest extant galleries to inform her study. Her research there and the Designmuseum Danmark into the economics and practices of sales and after-market mountings for transport and display, when published, will help many a conservator consider the origin and value of an extant lining.
Thomas further theorizes that the practice of entoilage– lining – allowed many posters, otherwise on unstable paper and with history of environmental exposure, to survive. The survey of the AGO collection reveals a diversity of lining materials (original and restorations), adhesives and histories of exposure. Entoilage is continued today by conservators; current practice may include a preliminary lining of paper or paper-lined textile, and pasting the conserved paper object to it. When considering treatment, risk to benefit must be calculated, pending the inherent vices present and media sensitivity. For those sensitive to aqueous methods, mechanical removal of a failing lining may be preferred. Here Thomas showed treatment slides, to demonstrating use of the Peachey Carbon Lifter for slipping through brittle adhesive, and with made great use of video to show a painstaking thread by thread removal of lining material.
Discussing replacement linings, Thomas previewed her mockup trials for different scenarios. Certainly, she says, each situation is unique and should be an individual, not mass, decision. In closing, she made a parallel to “collectable” street art today, which again is transitioning from its “low” roots in graffiti, to high art, what with the occasional pasteup, “wheat pasting” or sniping by street teams or individual artists such as Banksy, and lesser known artists. Who is collecting their work, and what will it look like into the future? These and other thoughts challenged the audience, which prompted a lively Q and A.
We look forward to considering these questions critically ourselves in future treatment, and to Thomas’ final paper in which she may address these more philosophical issues.
43rd Annual Meeting – Book and Paper Group Session, May 16, 2015. “Multitasking on a Shoestring: Storage and Display Mounts for Oversized Maps at the Library of Virginia” by Leslie Courtois
The talk began with an introduction to the Library, which as a state resource, also houses the archives and is mandated to make all content accessible, from the original object to digital access. The original building was built on a Jeffersonian model, which is supplemented with a massive offsite storage comprising some 97 million items over fifty-five miles of shelving, and yet has a very small staff for conservation and exhibit preparation. The Library has a very enthusiastic curator of maps, a benefactor with a interest in sponsoring maps scholarship and a robust interest group that seeks to use the collection. As such, Courtois presented a solution she has come up with that allows her to access and mount for display their extremely oversize maps without much additional help, using a modular system of her own invention and implementation.
With insights into the use of maps, “a highly aesthetic visual documentary material”, Courtois discussed several of local interest, including: the Mitchell (1755), the primary map used to define the nation after the revolution; the Sayer & Bennett map of the Chesapeake bay (1777); the John Henry map of Virginia (1770); and the “monster” Boye Map of Virginia (1826), printed from nine copper plates. Indeed, the scale of these editions permitted the publisher space for extreme detail and decorative elements that formerly were best perceived by the original user up close in their folded, pocketed format. The irony of the preservation rehousing, a 5mm thick Mylar and map folder hybrid, which permits flat storage and prevents improper folding damage, is that it can prevent the observer from seeing the details due to enforcing a certain distance due to its dimensions (up to 40” x 60” standardized, and custom for sizes beyond that). The flat housings also take up space on tables, if not exceeding the surface area available for reference, thus limiting the number that may laid out at one time, and lastly makes for an ergonomically unsound, and risky relationship of viewer to the object. For these reasons, the goal was to go vertical, for the least cost, and without having to rehouse the object in yet another expensive format.
The solution arrived at was to use Hexamount panels (or alternately, double laminate cross-directional corrugated board) as the vertical panel support, which are fastened to arms on independent wooden floor stands (or stanchions), hand-built by Courtois of simple materials and construction. The stands themselves are sturdy and functional, and once the panel is attached to swiveling arms by hook-and-loop tape, the feet are only visible part. The stand bases are made up of 3/4” furniture plywood, and two-by-fours are used as the risers. The arms to which the panels are attached, are fixed to the risers with a hex bolt that may be loosed and tightened, to allow for an angled presentation. There is no cross-brace or frame other than the panel itself, allowing the independent stands to be adjusted in width to each other based on the size of the Hexamount panel, allowing for flexibility of size. All told, the stands cost about $184 or about $30 each to make up six, including drill bits, wood, paint, wide Velcro ™ strip; the Hexamount runs about $87 per panel not including shipping.
The maps are supported on the panel using a pass through hinge system: the storage folder is pierced with wide slits above the map, and Mylar strapping is passed through matching slits in the panel behind and below and and affixed at the back.
Difficulties include supporting wide maps in the middle where sagging is a potential issue, but this can be resolved with additional strapping. Mounting and dismounting the large panel tends to be the stickiest issue, if you’ll pardon the pun. Once a large surface area of hook-and-loop tape attaches, it can be difficult to pry apart, so when setting up, it is helpful to place a removable barrier such as a slim ruler or other in between the hook and loop to allow for a break-away point if the strips are aligned improperly. For removal, it helps to have an assistant, and using a ruler to split the hook-and-loop as sort of zipper helps to peel them apart. (It was suggested during Q and A that leaving a few thin squares of Mylar or metal foil in place could also serve as a tool entry point for later removal; although visible tabs might present a security concern). For the Boye map, which was previously treated and edge mounted with a fabric extension similar to that which is used for quilt-hangings, a folded over fabric tube at the top allows for a rigid strut piece of corrugated or other material to be slid through the tube and which is tied in with linen tapes to the support board.
Courtois suggests a couple of further tips during the Q and A:
Michelle Facini, co-author of Big Paper, Big Problems (see also:poster and tables) noted that in responses to her Kress-funded survey even the use of the term oversized is challenging – every institution’s parameter for oversize is different! However, all face the same expensive choices, as sizes increase, so do material costs. Inquiring about the Boye map, Courtois replied that indeed, that one is rolled on a core for storage.
Courtois notes that this vertical, modular system allows the observer to get really close up in viewing the map, with little risk and much reward. The reward for all this hard work “is the engagement of the users – when you go to lengths to accommodate them, people really do value that effort.” In viewing candid shots from map society visits, and random visitors walking by encountering a map of size for perhaps the first time, this reviewer can only agree.
AIC’s 40th Annual Meeting, Revisiting Suction Table 101: Getting the Most from Your Table, Workshop by Robin Hodgson. May 8, 2012
Anyone who has seen either an RH Conservation Engineering tool or met Robin Hodgson in person will first be hit with a sense of inimitable style, and then realize what precision and detail underlies that surface. I’m not sure when I realized Robin gave workshops, but found myself quite jealous of some lucky student’s write up of theirs – probably at Winterthur some time ago. Writing from the perspective of a book and paper conservator of some 15+ years, I have worked in a number of labs with a variety of inherited suction equipment and tools ranging from the crafty conservator lab-made early designs, to Rube Goldbergian attachments, and early production models from Museum Services Corporation. Many inventive conservators have created interesting adaptations and and suggested designs along the way. Facing mechanical burnout on my current table that served my lab well for many years, I have been realizing that it is not enough to simply think the mechanicals are the only variable that cause a table or tool to work well – often the operator needs an upgrade too! With this in mind, I joined the workshop hoping to get some better understanding of the systems available and how they are used most efficiently.
Robin is a practicing conservator of wooden objects and furniture in Australia, and strove to develop a new range of tools after parting from conservation school, investing at least 5 years in product research development and design. While RH Conservation Engineering is one well known brand, a great effort was made in the workshop to discuss designs from other manufacturers with a non-competitive tone. In fact, Robin’s kind words for colleagues in the same market and openness to their work and innovations was a great pleasure, because this spoke more clearly to the participants’ needs for working and getting the best out of their current machines.
To a mixed audience of paintings, objects, textile and book, paper and archives conservators, Robin presented the technology and factor variables behind and the differences between such tools as hot lining suction tables, cold tables, and high pressure small machines such as fritted disc or other spot vacuums. This was extra useful from my perspective, to hear how different specialties approach the use of these. Hot lining tables were not traditionally part of my toolbox, but as book and paper, and especially photograph technology changes in contemporary art, I think we will be seeing more use and adaptation of these tools across specialties in the future and so found it exceptionally useful to understand the difference.
I was expecting more terrifying charts, graphs and calculations (perhaps a hangover from my training in interpreting HVAC controls, ASHRAE standards and hygrometric charts), but Robin sensibly minimized the use of complex physics and presented clean design/engineering specifications that showed the essential workflow of these types of machines, and where they can go wrong, or be improved. Some relative terms were discussed to better understand the language used in atmospheric pressure (hectopascals (hPa), (inHg), millibars (mb) and torr) so that participants could navigate from one manufacturer’s machine or country’s standard to another. Simple concepts and familiar tools (home vacuums) were used to relate comparable pressures available based on the sizes of the suction device.
Robin answered the participants’ many questions readily without needing to cut into the planned time for the hands-on workshop, especially considering my many probing questions, since blogging for others was on my mind! In retrospect, I now wish I had asked more about the workings of dipole and blower motors, horsepower, and how modular one can get with components. I certainly did get my money’s worth and look forward to improving performance on my table and devices when I get back to the lab, and recommend this workshop to any starting or mid-career or long time conservator.
Some links that may be of interest:
http://www.jstor.org/stable/3179681
http://jeffpeachey.wordpress.com/2009/04/02/thin-profile-suction-platen/
http://www.museumservicescorporation.com/equip.html
www.willard.co.uk/suction-equipment
http://universityproducts.ecomm-search.com/search?keywords=suction&submit.x=0&submit.y=0