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Historic Preservation - Technical Procedures

Spectitle:

Preservation Briefs: 25 The Preservation Of Historic Signs

Procedure code:

1043001S

Source:

Preservation Briefs 25, National Park Service, Pad

Division:

Specialties

Section:

Exterior Signs

Last Modified:

09/05/2012

Details:

Preservation Briefs: 25 The Preservation Of Historic Signs



PRESERVATION BRIEFS:  25

THE PRESERVATION OF HISTORIC SIGNS  

 

The link immediately below connects to the latest version of Preservation Brief 25:

 

http://www.nps.gov/history/hps/tps/briefs/brief25.htm


Michael J. Auer

This standard includes the bulk of information contained in the
original Preservation Brief developed by the National Park Service.
To obtain a complete copy of this brief, including figures and
illustrations, please contact:  

              Superintendent of Documen= ts
              P.O. Box 371954
              Pittsburgh, PA  1525= 0-7954

              GPO #024-005-01086-6
              $1.25

Please call the Publication Order Information Desk at 202/783-3238
or FAX 202/512-2250 to verify price and availability.  


"SIGNS" REFERS TO A GREAT NUMBER OF VERBAL, SYMBOLIC OR FIGURALMARKERS.  POSTERS, BILLBOARDS, GRAFFITI AND TRAFFIC SIGNALS,
CORPORATE LOGOS, FLAGS, DECALS AND BUMPER STICKERS, INSIGNIA ON
BASEBALL CAPS AND TEE SHIRTS: ALL OF THESE ARE "SIGNS."  BUI= LDINGS
THEMSELVES CAN BE SIGNS, AS STRUCTURES SHAPED LIKE HOT DOGS, COFFEE
POTS OR CHIPPENDALE HIGHBOYS ATTEST.  THE SIGNS ENCOUNTERED EACH
DAY ARE SEEMINGLY COUNTLESS, FOR LANGUAGE ITSELF IS LARGELY
SYMBOLIC.  THIS BRIEF, HOWEVER, WILL LIMIT ITS DISCUSSION OF
"SIGNS" TO LETTERED OR SYMBOLIC MESSAGES AFFIXED TO HISTORIC
BUILDINGS OR ASSOCIATED WITH THEM.

***INTRODUCTION***

Signs are everywhere.  And everywhere they play an important role
in human activity.  They identify.  They direct and decorate.  They
promote, inform, and advertise.  Signs are essentially social.
They name a human activity, and often identify who is doing it.
Signs allow the owner to communicate with the reader, and the
people inside a building to communicate with those outside of it.

Signs speak of the people who run the businesses, shops, and firms.
Signs are signatures.  They reflect the owner's tastes and
personality.  They often reflect the ethnic makeup of a
neighborhood and its character, as well as the social and business
activities carried out there.  By giving concrete details about
daily life in a former era, historic signs allow the past to speak
to the present in ways that buildings by themselves do not.  And
multiple surviving historic signs on the same building can indicate
several periods in its history or use.  In this respect, signs are
like archeological layers that reveal different periods of human
occupancy and use.

Historic signs give continuity to public spaces, becoming part of
the community memory.  They sometimes become landmarks in
themselves, almost without regard for the building to which they
are attached, or the property on which they stand.  Furthermore, in
an age of uniform franchise signs and generic plastic "box" signs= ,
historic signs often attract by their individuality: by a clever
detail, a daring use of color and motion, or a reference to
particular people, shops, or events.  Yet historic signs pose
problems for those who would save them.  Buildings change uses.
Businesses undergo change in ownership.  New ownership or use
normally brings change in signs.  Signs are typically part of a
business owner's sales strategy, and may be changed to reflect
evolving business practices or to project a new image.

Signs also change to reflect trends in architecture and technology:
witness the Art Deco and Depression Modern lettering popular in the
1920s and 1930s, and the use of neon in the 1940s and 1950s.

The cultural significance of signs combined with their often
transitory nature makes the preservation of historic signs fraught
with questions, problems, and paradoxes.  If the common practice in
every period has been to change signs with regularity, when and how
should historic signs be kept?  If the business is changing hands,
how can historic signs be reused? The subject is an important one,
and offers opportunities to save elements that convey the texture
of daily life from the past.

This Brief will attempt to answer some of the preservation
questions raised by historic signs.  It will discuss historic sign
practices, and show examples of how historic signs have been
preserved even when the business has changed hands or the building
itself has been converted to a new use.


***HISTORIC SIGN TYPES AND PRACTICES***

PRE-NINETEENTH CENTURY:

American sign practices originated largely in Europe.  The earliest
commercial signs included symbols of the merchant's goods or
tradesman's craft.  Emblems were mounted on poles, suspended from
buildings, or painted on hanging wooden boards. Such symbolic signs
were necessary in a society where few could read, although verbal
signs were not entirely unknown. A sheep signified a tailor, a
tankard a tavern.  The red and white striped pole signifying the
barbershop, and the three gold balls outside the pawnshop are two
such emblems that can occasionally be seen today.  (The barber's
sign survives from an era when barbers were also surgeons; the
emblem suggests bloody bandages associated with the craft.  The
pawnbroker's sign is a sign of a sign: it derives from the coat of
arms of the Medici banking family.)

Flat signs with lettering mounted flush against the building
gradually replaced hanging, symbolic signs.  The suspended signs
posed safety hazards, and creaked when they swayed in the wind:
"The creaking signs not only kept the citizens awake at night, but
they knocked them off their horses, and occasionally fell on them
too."  The result, in England, was a law in 1762 banning large
projecting signs.  In 1797 all projecting signs were forbidden,
although some establishments, notably "public houses," retained the
hanging sign tradition.

By the end of the eighteenth century, the hanging sign had declined
in popularity.  Flat or flush-mounted signs, on the other hand, had
become standard.  Like symbolic signs, however, the tradition of
projecting signs has survived into the present.


NINETEENTH CENTURY SIGNS AND SIGN PRACTICES:

Surviving nineteenth-century photographs depict a great variety of
signs.  The list of signs discussed here is by no means exhaustive.

Fascia signs, placed on the fascia or horizontal band between the
storefront and the second floor, were among the most common.  The
fascia is often called the "signboard," and as the word implies,<= br> provided a perfect place for a sign--then as now.  The narrowness
of the fascia imposed strict limits on the sign maker, however, and
such signs usually gave little more than the name of the business
and perhaps a street number.

Similar to fascia signs were signs between the levels of windows
across the upper facade.  Such signs were mounted on horizontal
boards or painted on the building.  Signs of this type tended to
use several "lines" of text, the name of business and short
description, for example.  The message, reading from top to bottom,
sometimes covered several stories of the building.  Other painted
signs presented figures, products, or scenes.  Such signs were
typically more vertical than horizontal in emphasis.  Whether such
painted signs featured text or images, they became major features
of the building, as their makers intended them to be.  The building
itself often became a backdrop for the sign.

Signs in the form of plaques, shields, and ovals were used on many
nineteenth-century buildings.  Such signs had the advantage of
being easily replaced as tenants came and went. They also easily
incorporated images as well as lettering.

Hanging or projecting signs, both lettered and symbolic, were also
common in the nineteenth century, although less so than previously.
Projecting signs were often paired with another at a 45=F8 angle for
increased visibility.  Occasionally a sign would stretch out from
the building across the sidewalk, supported by a post at the
street.

Goldleaf signs, and signs painted or etched on glass in windows,
doors and transoms were quite common.

Porcelain enamel signs were also very popular in the latter half of
the nineteenth century and into the mid-twentieth century.  Signs
carved from stone or wood also appeared frequently, especially on
institutional buildings.  Painted shutters and even window shades
provided additional advertising space.

Posters found their way into display windows when they weren't
pasted onto the building.  Sidewalk signs or "sandwich boards&quo= t;
offered another chance to catch the eye of any passerby not
watching the graphics overhead.

Nineteenth-century tenants looking for additional advertising space
found it in unexpected places.  They used the entrance steps to
mount signs in a variety of ways: Handrails, risers, skirts, and
balusters sported signs that gave businesses on upper levels a
chance to attract notice.

Awnings offered other opportunities for keeping a name before the
public.  The fringe or skirt of the awning, as well as the panel at
the side were the usual places for a name or street number.  Flags,
particularly hung from the upper floors, and banners, sometimes
stretching across the sidewalk, also appeared on buildings.

Rooftop signs appeared with greater frequency in the second half of
the nineteenth century than previously.  Earlier rooftop signs
tended to be relatively simple--often merely larger versions of the
horizontal signs typically found on lower levels.  Late in the
century the signs became more ornate as well as more numerous.
These later rooftop signs were typically found on hotels, theaters,
banks and other large buildings.

The sign types described here were not used in isolation. Window
and awning signs attracted sidewalk pedestrians and people in the
street.  Upper level signs reached viewers at greater distances.
If signs were numerous, however, they were nonetheless usually
small in scale.

As the century wore on, signs increased in size and scale. Wall
signs several stories high were not uncommon in the second half of
the century.  This development reflects changes in urban life as
the century headed to its close.  Cities were experiencing rapid
population growth.  Buildings became bigger and taller.  Elevated=
trains and electric trolleys increased the pace of city life.  And
when it comes to signs, speed alters scale.  The faster people
travel, the bigger a sign has to be before they can see it.

TWENTIETH CENTURY SIGNS AND SIGN PRACTICES:

The advent of the twentieth century approximately coincided with
the coming of electricity, which gave signs light and, later,
movement.  Illuminated signs were not unknown before electricity.
An advertisement printed about 1700 mentioned a nighttime sign lit
by candles, and in 1840 the legendary showman P.T. Barnum built a
huge sign illuminated by gas.  But electricity was safer and
cheaper than candles, kerosene and gas.  Its widespread use gave
signs a prominence they retain today: illuminated signs dominate
the streets at night.

Electricity permitted signs to be illuminated by light shining onto
them, but the real revolution occurred when lightbulbs were used to
form the images and words on signs.  Lightbulbs flashing on and off
made new demands on the attention of passersby.  Lightbulbs
blinking in sequence could also simulate movement.  Add this
property to the mix, and a dramatic transformation of American
streets resulted.

Moving signs were not unknown prior to the advent of electricity,
for wind-driven signs had made their appearance in the nineteenth
century.  But electricity gave signs an unparalleled range of
motion.  This movement added yet another element to the life of the
street.

Neon is another great twentieth-century contribution to the
signmaker's art.  "Neon," coined from the Greek word for "new," is
a "new gas."  It has the useful property of glowing when an
electric charge passes through it.  (Argon, krypton, xenon and
helium share this property.  Only neon and argon, however, are
typically used in commercial signs.)  Encased in glass tubes shaped
into letters or symbols, neon offered signmakers an opportunity to
mold light into an infinite variety of shapes, colors, and images.
Combined with an electric timer, the neon tubing could present
images moving in succession.

Neon first appeared in signs in the 1920s, and reached its height
of popularity in the 1940s.  The first documented neon commercial
sign in the United States was at a Packard Motor Car dealership in
Los Angeles in 1923.  After a period of decline, it underwent a
renaissance, beginning in the 1970s. Artists experimented with neon
as a conscious art-form, and several notable architects further
helped in its revival.  Renewed interest in this colorful medium
also sparked interest in preserving historic neon signs.

Along with such developments as the coming of electricity and then
neon, stylistic movements influenced twentieth-century signs.  In
particular, Art Deco and Streamlined Moderne affected not just
buildings, but their signs as well.

Architects working in these styles often integrated signs and
buildings into a unified design.  This was particularly true of
storefronts built using pigmented structural glass, commonly known
as "Carrara glass," and porcelain enamel on steel panels.  T= hese
materials allowed words and images to be etched into the glass or
enamel, or to be constructed in different colors and patterns as
part of an overall design for the building.  Such storefronts were
popular from the 1920s into the 1940s.

As the century advanced, new styles took hold.  The late 1950s
brought signs with fins, star bursts, and other images reflecting
a new fascination with outer space.

In the decades after World War II signs were also transformed by a
group of materials now known generically as "plastic." Plastic had
several advantages over wood, metal and other traditional sign
materials.  As the name indicates, "plastic" can take almost any
shape.  It can also take almost any color. Plastic is translucent.
Lit from behind, it appears to glow. It is relatively durable.
Above all, it is inexpensive, and can be mass produced.  Plastic
quickly became the dominant sign material.

Another profound influence on signs in this period stemmed from
business trends rather than from technological breakthroughs or
design movements: the rise of chain stores and franchises.
National firms replaced many local businesses.  Standard corporate
signs went up and local trademarks came down.  The rise of mass
culture, of which the national chain is but one expression, has
meant the rise of standardization, and the elimination of regional
differences and local character.

The decline of gold-leafing and other traditional sign techniques
contributed to these trends.  Mass-produced signs have replaced
local signs that differed from owner to owner and from signmaker to
signmaker.  The result is not just sameness, but impersonality as
well.  It is becoming rarer, for example, to find owners' names on
signs.  Whether the trend toward sameness can successfully be
resisted is yet to be seen.  (Some crafts, such as gold-leafing and
porcelain enameling, for example, have experienced a revival of
sorts.) But the preservation of historic signs is one way to ensure
that at least some of these expressions of local history continue
to enliven our streets.


***SIGN REGULATION***

Historic commercial areas have customarily been a riot of signs.
Yet if clutter has ample precedent, so do efforts to control it.
Early attempts to regulate signs in this country include those of
professional associations of advertisers, such as the International
Bill Posters Organization of North America, founded in St. Louis in
1872.

However, early efforts by municipalities to enact sign regulations
met with disfavor in the courts, which traditionally opposed any
regulatory effort based on aesthetic concerns.  Early successes in
the legal arena, such as the 1911 case, St. Louis Gunning
Advertising Company v. City of St. Louis, were realized when
proponents of sign controls argued that signs and billboards
endangered public health and safety.

Yet gradually courts found merit in the regulation of private
property for aesthetic reasons.  In 1954 the U.S. Supreme Court
handed down the landmark decision, Berrnan v. Parker, in which the
court declared: "It is within the power of the legislature to
determine that the community should be beautiful as well as
healthy, spacious as well as clean, well balanced as well as
carefully patrolled."

With the blessing of the courts, communities across the nation have
enacted sign controls to reduce "urban blight."  And where historic
buildings are concerned, the growth of local review commissions has
added to the momentum for controls in historic districts.

Typically, sign controls regulate the number, size and type of
signs.  In some cases, moving or projecting signs are prohibited.
Often such ordinances also regulate sign placement--owners are told
to line up their signs with others on the block, for example.
Materials, likewise, are prescribed: wood is encouraged, plastic
discouraged or forbidden altogether.  Sign controls often specify
lighting sources: indirect illumination (light shining onto the
sign) is often required instead of neon tubing, bare lightbulbs, or
"back lighting," used in most plastic signs.  Some ordinance= s
forbid lighting completely.  (Neon, especially, is still held in
disfavor in some areas.)  Finally, ordinances sometimes require
signs to be "compatible" in color and other design qualities with
the facade of the building and the overall appearance of the
street.

Existing signs frequently do not meet requirements set forth in
sign controls.  They are too big, for example or project too far
from the building.  Typically, sign ordinances permit such
"nonconforming" existing signs to remain, but only for a specifie= d
period, after  which they must be removed.  If they need repairbefore then, or if the business changes owners, they must likewise
be removed.  Sign controls offer communities the chance to reduce
visual blight.  They can also assist in producing both a new
visibility and a new viability for historic commercial districts.
Yet sign ordinances are not without problems.  Sign controls
satisfy contemporary ideas of "good taste."  But "bad taste" has
ample historic precedent.  In any case, tastes change.  What is
tasteful today may be dated tomorrow.  Sign controls can impose a
uniformity that falsifies history.  Most historic districts contain
buildings constructed over a long period of time, by different
owners for different purposes.  The buildings reflect different
architectural styles and personal tastes.  By requiring a standard
sign "image" in such matters as size, material, typeface and other
qualities, sign controls can mute the diversity of historic
districts.  Such controls can also sacrifice signs of some age and
distinction that have not yet come back into fashion.  Neon serves
as an instructive example in this regard, once "in," then "o= ut,"
then "in" again.  Unfortunately, a great number of notable signs
were lost because sign controls were drafted in many communities
when neon was "out."  Increasingly, however, communities are
enacting ordinances that recognize older and historic signs and
permit them to be kept.  The National Park Service encourages this
trend.


***SIGN AS ICON***

Signs often become so important to a community that they are valued
long after their role as commercial markers has ceased.  They
become landmarks, loved because they have been visible at certain
street corners--or from many vantage points across the city--for a
long time.  Such signs are valued for their familiarity, their
beauty, their humor, their size, or even their grotesqueness.  In
these cases, signs transcend their conventional role as vehicles of
information, as identifiers of something else.  When signs reach
this stage, they accumulate rich layers of meaning.  They no longer
merely advertise, but are valued in and of themselves.  They become
icons.


***PRESERVING HISTORIC SIGNS***

Historic signs can contribute to the character of buildings and
districts.  They can also be valued in themselves, quite apart from
the buildings to which they may be attached.  However, any program
to preserve historic signs must recognize the challenges they
present.  These challenges are not for the most part technical.
Sign preservation is more likely to involve aesthetic concerns and
to generate community debate.  Added to these concerns are several
community goals that often appear to conflict: retaining diverse
elements from the past, encouraging artistic expression in new
signs, zoning for aesthetic concerns, and reconciling business
requirements with preservation.

Preserving historic signs is not always easy.  But the intrinsic
merit of many signs, as well as their contribution to the overall
character of a place, make the effort worthwhile.  Observing the
guidelines given below can help preserve both business and history.

RETAINING HISTORIC SIGNS:  

Retain historic signs whenever possible, particularly when they
are:

-  Associated with historic figures, events or places.

-  Significant as evidence of the history of the product,  busine= ss
or service advertised.

-  Significant as reflecting the history of the building or the
development of the historic district. A sign may be the only
indicator of a building's historic use.

-  Characteristic of a specific historic period, such as gold leaf
on glass, neon, or stainless steel lettering.

-  Integral to the building's design or physical fabric, as when a
sign is part of a storefront made of Carrara glass or enamel
panels, or when the name of the historic firm or the date are
rendered in stone, metal or tile. In such cases, removal can harm
the integrity of an historic property's design, or cause
significant damage to its materials.

-  Outstanding examples of the signmaker's art, whether because of
their excellent craftsmanship, use of materials, or design.

-  Local landmarks, that is, signs recognized as popular focal
points in a community.  

-  Elements important in defining the character of a district, such
as marquees in a theater district.

MAINTAINING AND REPAIRING HISTORIC SIGNS:

Maintenance of historic signs is essential for their long term
preservation.  Sign maintenance involves periodic inspections for
evidence of damage and deterioration.

Lightbulbs may need replacement.  Screws and bolts may be weakened,
or missing altogether.  Dirt and other debris may be accumulating,
introduced by birds or insects, and should be cleaned out.  Water
may be collecting in or on sign cabinets, threatening electrical
connections.  The source of water penetration should be identified
and sealed.  Most of these minor repairs are routine maintenance
measures, and do not call for special expertise.  All repairs,
however, require caution.  For example, electricity should be
turned off when working around electric signs.

More extensive repairs should be undertaken by professionals. The
sign industry is a large and active one.  Sign designers,
fabricators and skilled craftsmen are located throughout the
country.  Once in danger of being lost altogether, gold leaf on
glass and porcelain enamel are undergoing revivals, and the art of
bending neon tubes is now widely practiced.  Finding help from
qualified sources should not be difficult.  Before contracting for
work on historic signs, however, owners should check references,
and view other projects completed by the same company.

Major repairs may require removal of the sign to a workshop. Since
signs are sometimes damaged while the building is undergoing
repair, work on the building should be scheduled while the sign is
in the shop.  (If the sign remains in place while work on the
building is in progress, the sign should be protected).

Repair techniques for specific sign materials are discussed below.
The overall goal in repairs such as supplying missing letters,
replacing broken neon tubing, or splicing in new members for
deteriorated sections is to restore a sign that is otherwise whole.
Recognize, however, that the apparent age of historic signs is one
of their major features.  Do not "over restore" signs so that all
evidence of their age is lost, even though the appearance and form
may be recaptured.

REUSING HISTORIC SIGNS:

If a building or business has changed hands, historic signs
associated with former enterprises in the building should be reused
if possible by:

-  Keeping the historic sign unaltered.  This is often possibleeven when the new business is of a different nature from the old.
Preferably, the old sign can be left in its historic location.
Sometimes, however, it may be necessary to move the sign elsewhere
on the building to accommodate a new one.  Conversely, it may be
necessary to relocate new signs to avoid hiding or overwhelming
historic ones, or to redesign proposed new signs so that the old
ones may remain.  (The legitimate advertising needs of current
tenants, however, must be recognized).  NOTE:  Keeping the old sign
is often a good marketing strategy.  It can exploit the recognition
value of the old name and play upon the public's fondness for the
old sign.  The advertising value of an old sign can be immense.
This is especially true when the sign is a community landmark.

-  Relocating the sign to the interior, such as in the lobby or
above the bar in a restaurant.  This option is less preferable than
keeping the sign outside the building, but it does preserve the
sign, and leaves open the possibility of putting it back in its
historic location.

-  Modifying the sign for use with the new business.  This may not
be possible without destroying essential features, but in some
cases it can be done by changing details only.  In other respects,
the sign may be perfectly serviceable as is.  

-  If none of these options are possible, the sign could be donated
to a local museum, preservation organization or other group.

REPAIRING HISTORIC SIGN MATERIALS:

Porcelain Enamel:  

    Porcelain enamel is among the most durable of materials used
    in signs.   Made of glass bonded onto metal (usually steel) at
    high temperatures, it keeps both its high gloss and its colors
    for decades.  Since the surface of the sign is essentia= lly
    glass, porcelain enamel is virtually maintenance free; dirt<= br>     can be washed off with soap and water and other glass
    cleaners.

    Porcelain enamel signs can be damaged by direct blows from     stones and other sharp objects.  If both the enamel surface
    and the undercoat are scratched, the metal surface can rust at
    the impact site.  Because the bond between glass and metal is
    so strong, however, the rust does not "travel" behind the
    glass, and the rust is normally confined to localized areas.
    The sign edges can also rust if they were never enamelled.  To
    treat the problem, clean the rust off carefully, and touch-u= p
    the area with cold enamel (a type of epoxy used mostly in
    jewelry), or with enamel paints.

    Dents in porcelain enamel signs should be left alone.
    Attempting to hammer them out risks further damage.

Goldleaf or Gilding:

    Goldleaf or gilding is both elegant and durable.  These=
    properties made it among the most popular sign materials in
    the nineteenth and early twentieth centuries. Surface-gilded=
    signs (for example, gilded raised letters or symbols found on
    the exterior) typically last about 40 years.  Damage to these
    signs occurs from weather and abrasion.  Damage to gilded
    signs on glass normally occurs when the protective coating     applied over the gilding is removed by harsh cleaning
    chemicals or scratched by scrub brushes.  The sign can then
    flake upon subsequent cleanings.

    Historic gilded signs can be repaired, typically by regildin= g
    damaged areas.  An oil size is painted on the surface.  The
    gold leaf is applied when the surface has become sufficientl= y
    "tacky." Similarly, historic "reverse on glass" gold leaf
    signs can be repaired by experts.  A sample of the flaking
    sign is first taken to determine its composition.  Reve= rse on
    glass signs use gold leaf ranging from 12 to 23 karats.  The
    gold is alloyed with copper and silver in varying amounts for
    differences in color.  (Surface gilding--on raised letters,
    picture frames and statehouse domes--uses 23 karat gold.  Pure
    gold, 24 karat, is too soft to use in such applications.)  The
    damaged portions of the sign are then regilded in the same     manner as they were done historically.  The inside surface of
    the glass is coated with a gelatin, gold leaves about three<= br>     inches square are then spread over the area.  The new letter
    or design is then drawn in reverse on the new leaf, and coated
    with a backing paint (normally a chrome yellow).  With the new
    design thus sealed, the rest of the leaf is removed.  T= he sign
    is then sealed with a clear, water-resistant varnish.

    Gilded signs, both surface and reverse on glass, can be
    cleaned gently with soap and water, using a soft cloth.
    Additionally, for glass signs, the varnish backing should be
    replaced every seven years at the latest.

Neon:

    Neon signs can last 50 years, although 20-25 years is more     typical.  When a neon sign fails, it is not because the gas
    has "failed," but because the system surrounding it has broken
    down. The glass tubes have been broken, for example, thus
    letting the gas escape, or the electrodes or transformers have
    failed.  If the tube is broken, a new one must be made by a
    highly skilled "glass bender."  After the hot glass tube has
    been shaped, it must undergo "purification" before being
    refilled with gas.  The glass and the metal electrode at the
    end of the tube are heated in turns.  As these elements become
    hot, surface impurities burn off into the tube.  The resulting
    vapor is then removed through "evacuation,"  = the process of
    creating a vacuum.  Only then is the "neon" gas (neon or
    mercury-argon) added.  Neon gives red light, mercury-ar= gon
    produces blue.  Other colors are produced by using colored
    glass and any of dozens of phosphor coatings inside the tube.
    Green, for example, can be produced by using mercury-argon in
    yellow glass.  Since color is so important in neon signs, it
    is vital to determine the original color or colors.  A neon
    studio can accomplish this using a number of specialized
    techniques.

    A failing transformer can cause the neon sign to flicker
    intensely, and may have to be replaced.  Flickering neon can
    also indicate a problem with the gas pressure inside the tube.
    The gas may be at too high or too low a pressure.  If so, the
    gas must be repumped.

    Repairs to neon signs also include repairs to the surroundin= g
    components of the sign.  The "metal cans" that often serve as
    backdrops to the tubing may need cleaning or, in case of rust,
    scraping and repainting.


***NEW SIGNS AND HISTORIC BUILDINGS***

Preserving old signs is one thing.  Making new ones is another.
Closely related to the preservation of historic signs on historic
buildings is the subject of new signs for historic buildings.
Determining what new signs are appropriate for historic buildings,
to the building.  











 


Preservation Brief 25, painted signed, historic signs, preservation of historic signs, preservation of painted signs, painted sign on masonry