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Articles
LIGHTING IS THE WORD IN LIGHTING RESTORATION:
Lighting technologies create new issues for the historic project.
By John M. Corbett
INSIDE, OUTSIDE, EVERYWHERE I GO, IT RAINS. Gas jets alight, a 1813
City Hall Park lamp awaits its turn in the "storm machine" at Aurora Lampworks'
Brooklyn studio where it will have a chance to demonstrate its ability to keep
burning in all weather. Note beveled glass and cast finial, weighty and
problematic aftermarket additions to the original work.
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Lighting fixtures distinguish themselves from other building fabric by
delivering a commodity much affected by changes in taste and new technology.
By understanding how the client's expectations of lighting performance may have
evolved, a durable specification can be developed, one that will survive the
project intact and continue to serve the client for years to come. This is
restoration, after all, and the goal is to develop solutions that can endure
right along with the historic fabric of which they are a part. Appetite for
light in public places has grown and so has the number of technologies capable
of delivering it in an acceptable form. The historic lighting artisan can
aspire not just to restoration, the mere recovery of what was, but to better
delivery of natural looking, energy efficient light. In so doing, however,
a number of constituencies are encountered which may be unfamiliar to most
restoration professionals. Lighting choices have consequences that affect
security, energy costs, purchasing inventory and maintenance costs. It is
not always possible to please everybody, but the time to try is at the
beginning of the project, during the design phase.
New technologies can offer compelling benefits but a light source upgrade
is rarely simply a matter of swapping parts. Dawn Ladd, owner of
Aurora Lampworks, a lighting restoration
specialist from Brooklyn, NY, observes that designing upgrades to historic
lighting fixtures is done backwards from how fixture design is generally taught
and practiced. It is most efficient to start with the light source and
design the fixture around its requirements, but the lighting restoration
professional must do the reverse, transforming the existing fixture into a
suitable platform for new expectations and new technology. As an example,
she cites a current project, ten bronze deco exterior fixtures at the 1930's
Westchester County Office Building in White Plains. Evaluated by a
conservator (see photo caption), recreation of their original antique bronze
finish has been specified. It is possible that the existing light source,
incandescent, will be reproduced as well because incandescent furnishes a
warm, familiar light, with excellent rendering of colors. It is, however,
expensive to run and more expensive to maintain as the lamps need to be
frequently replaced. Metal halide, by contrast, is a more energy efficient
source and one with more modest maintenance requirements. Formerly, it cast
a greenish glare, but with recent corrections in its ability to produce the
full spectrum of light, it has found more frequent employment in important
spaces. The savings in energy and labor offered by metal halide over time
will be substantial, but they must be balanced against the initial cost of
adapting the fixtures to the new light source. New mount locations will
be required and, since it requires a separate ballast, additional wiring
chases, internal shelving and maintenance access as well. No upgrade
specification for these fixtures can be considered reliable until it
has been demonstrated and approved under field conditions. This can
require construction of a demonstration mockup as every light source has its
own physical configuration and characteristic way of distributing light, both
of which need to be evaluated in terms of the existing historic fixture.
Such preparation may seem tedious but it is the most efficient way to develop
a design that effectively addresses all client interests.
The long and varied career of the lampposts in City Hall Park in New York
illustrates how the interplay of lighting constituencies and evolving tastes
for light can force a redesign even without any obvious technology upgrade.
Four fixture heads dating from 1813, they were originally gas, then electrified
at the turn of the 20th century, changed to high pressure sodium in the 60's,
metal halide in the 80's and then back to gas in the year 2000. The current
gas conversion was lodged in the original soldered sheet metal housing which
itself was retrofitted with new heavy beveled glazing and an eight pound
finial eagle cast out of bronze. To insure the gas flame was visible amidst
high levels of background light in the Park, three gas jets were specified
where, it was suspected, there had originally only been one. With the added
weight of the new design elements and the suspected additional heat of the gas
jets, the solder joints began to fail and the lamp housings collapsed.
It would appear that an unintended accumulation of factors such as the weight
of the design retrofit, a decision to restore a historical light source and
the need to compete with modern levels of background light combined to
overwhelm the stability of the original design. A new design was required
that could safely support these elements while maintaining the existing look
and fabric. Aurora rebuilt the fixtures around a steel armature capable of
supporting the weight of the additional design elements and equipped them
with concealed vents sufficient to prevent overheating. There was no change
in the light source, but since the venting detail was unproven, Aurora tested
the design in their in-shop "storm machine," an assembly of fans
and spray nozzles, to confirm its ability to maintain the gas flame in wind
driven rain. With a tested design, the fixtures in City Hall Park are now
well matched to their light source.
Durable historic buildings are best served by a durable lighting design
but the principles for developing such specifications are not universally
understood. Aurora Lampworks believes that the field would benefit if
established standards for the performance of restored lighting fixtures were
to find wider distribution. Until they do, clients are advised to consider
whether language such as "restore, as necessary" or "upgrade, making alterations
as necessary" completely address all their potential concerns. Lighting
restoration is only in part the restoration of artifacts. The recommendations
of the conservator (see sidebar) are not the end of the design process but
often just the beginning.
LAMP BACKWARDS STORY TELLS. A 1930 bronze fixture at the Westchester
County Building reveals its layered history, peeling brown paint and,
visible beneath, a heavy coat of verdigris, neither matching the intent of
the designer. Verdigris is a natural buildup of oxides while the paint
remains from a crude attempt to suppress oxidation and to approximate the
original finish. That finish, "antiqued" bronze, was discovered
on an unexposed surface. It will be recreated using the original technique,
torch applied hot-patination, and further oxidation prevented by a coat
of clear lacquer.
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CONSERVATOR'S TOOLBOX
Discovering the original intent of the designer is a most valuable tool for
producing a satisfactory specification for the conservation of historic
lighting fixtures, according to Mark Rabinowitz, architectural conservator
with Conservation & Sculpture Co. These artifacts were produced by
anonymous but often very sophisticated designers and the effects that they
achieved are frequently masterful and subtle. The means by which they
achieved them are not always reproducible under today's conditions, but they
are always useful to know, as they often point directly toward the simplest,
most elegant design solution. Previous "restorations" and the attrition of
time may have obscured finishes or destroyed detail, but you may uncover
its original form by using the tools below, listed in ascending order of
invasiveness:
- AN OPEN MIND. Don't assume, verify. These artifacts often
employ considerable artifice to create calculated illusions.
- RESEARCH. Check client archives for documents that may identify a
known manufacturer. Lighting was often produced by sizeable companies so
seek out period catalogs and museum collections. Search the site for examples
which may have escaped alteration by being in storage or located in an
underutilized space.
- MAGNIFYING GLASS. Clues may be right in front of you, if you
look closely enough.
- MAGNET. Base metal can be bronzed or otherwise concealed,
so don't assume.
- DETERGENT. Clean it up so that you can see what you are
looking at, distinguish mere dirt from oxides or even finishes.
- DISASSEMBLY. Look for hidden surfaces in their original
condition that may have escaped damage or alteration.
- SOLVENTS. These will damage the finish, which is kind of
the idea. Finishes will reveal their composition by resisting some solvents
and dissolving in others. Look for tints or pigments to dissolve out
of "clear" lacquers.
For further information about architectural conservators and conservation, visit The American Institute for Conservation of Historic and Artistic Works.
Lighting Restoration & Repair Specialists:
Aurora Lampworks, Inc., Brooklyn NY, Lighting Restoration and Retrofitting.
Griffin Brothers and Company, LLC, Farmington CT, Lighting Restoration. Reproduction Lighting.
Fine Architectural Metalsmiths, Chester NY, Custom Ornamental Ironwork.
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