Displaying & Lighting Glass

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2008-04-17 Rev. 2008-11-29, 2009-07-15

Glass & Light Center

Light is the leading requirement of enjoying glass.  Localized light adds to the experience with a few exceptions such as paperweights and paperweight style vessels where the detailed inclusions are featured.  Lamps, windows, vessels, patterned paperweights, and other glass objects provide additional rewards when spot lighted, up lighted, washed or otherwise provided with feature lighting.  This page discusses a few of those methods.

various MR16 fixtures in booths at Ft.Worth Main St. Art FestWASH LIGHT - If glass is displayed with many pieces in the same space, be it a set of shelves or across a long shelf, it may not be practical to highlight individual pieces, so that a restricted wash of light attracts the eye to the display compared to the darker surroundings.  Because of its "white" characteristics and easy aiming, halogen lighting in the form of high or low voltage floods is a favorite for this purpose.  MR-16 low voltage miniature reflector lamps are interchangeable in most fixtures that take them and come in spot, narrow, medium and wide flood in various wattages.  Because they are 12 volts, safe for contact, the housings can be placed on exposed wires, rods, or brackets that allow adjustment in space including placement in midair with the slenderest of supports.  120 volt medium base screw in floods and spots are also available in several sizes - all of which have heavy glass envelopes for capturing hot fragments in the event of failure.   Caution: Any halogen bulb where the small cartridge surrounding the filament is exposed must not be touched with the bare hands, the oils and acids if left on the quartz will lead to early failure - use a cloth to handle.  Multiple shelves may require careful arrangement of the glass so that shadows of pieces on the higher shelves avoid the lower pieces.

UP LIGHT - Up lighting is available in three significant forms - a transparent shelf of glass or plastic with lights shining through it, a frosted shelf with light immediately below it, and individual lights directly below each piece.
Clear shelves lighted from below allow placement of fixtures below eyesight while putting shadows and light patterns on the walls behind the glass.  Often it is not possible to light the front or upper parts of opaque pieces so this may not be the best choice unless some top lighting is also available.
Frosted shelves with the lights directly below are ideal for fluorescent bulbs which given even light and solve the problem of heat in a confined space.  A shelf can be made rather thick for housing even larger diameter bulbs if the thickness tapers to a relatively thin front edge and newer T8 bulbs take two-thirds the space of T12 (the number is 8ths of an inch in the diameter.)  With care it is easy to build custom units, the primary requirement being a grounded metal plate within 1/2" of the bulb along its length and a metal housing for the connections if the glass/plastic lifts off.
Up lighting for individual pieces normally requires matching the diameter of the base to a mask that directs the light into the base and shadows the sides.  Obviously, this works better with non-opaque pieces.  The mask can be thin cardboard on a clear or translucent surface with the light below, but more spectacular results occur when there is a fixture closely matched to the piece, perhaps matted to exact size.  One caution is heat - an MR16 or other source placed closely below a heavy chunk of glass can break the glass.  Placing it lower down with vent holes or providing forced air via a quiet computer fan may be required.

SPOT LIGHT - Lights picking out individual pieces of glass and providing sharp shadows require the most setup but may produce the greatest effect.  As with wash lights, the availability of a variety of wattages and beam spreads of bulbs allows more convenient lighting from conducting wire mounts.  For larger pieces of glass and those lighted from further away, small fixtures with lenses modeled after stage lighting allow placing a small circle of light 8-10 feet away from the fixture.  There are a huge number of fixtures available for concealed lighting with the trade off that once installed, the object can be moved but the fixture is fixed.

WINDOW LIGHT - Window light is back lighting and provided the actual window does not glare and overwhelm the glass, can be delightful.  Light from the east, north, or west is more likely to avoid glare most of the day compared to south light although a shade may subdue the south light appropriately.   Using a window also provides a more or less shifting pattern of light and shadow to play through the glass which can add interest to long term viewing.  Providing an artificial back light that approaches the quality of outdoor light is difficult and seems rarely tried.
A certain amount of caution is needed when window light exposes the glass to direct sunlight, which may happen with a low sun in winter even when most of the year is indirect.  Spherical glass objects - mostly clear paperweights, globes at the base of vases, etc. - can focus the sun's rays into a bright spot that may heat the shelf or paper on the shelf to the point that charring may occur, perhaps leading to a fire.

TIMERS - If the purpose of the lighting is to show off pieces to the best advantage when guests are present, then a switch may be the best choice for getting the light on.  In olden days it was common to have an outlet connected to a switch near the door to allow a floor or table lamp to be turned on upon entering.  This seems much less common today.  However, a variety of remote switching options are available to provide the same convenience and effect.  These range from sound activated ("Clap On, Clap Off") to single and multifunction wireless remotes (X10, Plug n'Power)
For glass in a case, modules are available which have a wire that connects a hinge to a control box allowing the hinge to be a touch switch for low, medium, and high lighting.  The modules can be used with any metal object: the human body's capacitance is sensed to change the setting.
But timers are the best choice if the purpose of the lighting is to delight the owner.  As part of the ambient lighting, the indirect light from the lighted glass provides a background for the room and accents the glass, while not hurting the security for a lived in look.  Timers come in electronic and mechanical form and most suffer from the problem of losing track of time if the power fails.  A few free standing electronic units have a battery backup on the time so they can continue correct timing of light when power returns.  The X10 system, besides allowing remote control, provides free standing timers as well as a unit programmed from a computer that retains settings through a power failure.  Enhanced software can change the settings to match changing sunrise and sunset times during the year.   More complicated built in lighting, security, and audio setups are becoming available as household control appliances.

Contact Mike Firth