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.”
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AIC Blog Archives: Conservators Converse
Former Blog of the American Institute for Conservation