Art glass display lighting
Jim Miller
using AR111 lamps over MR16s? Should I be concerned about UV emissions?
Are multi-faceted points better than single point sources? What is the best
angle to light from (above)? Thanks for any input
Jim Miller
TKM
"Jim Miller" <j...@millerlightassoc.com> wrote in message
news:12mmdqn...@corp.supernews.com...
>I am lighting a very high end art glass display. Are there advantages to
>using AR111 lamps over MR16s?
Look at the candlepower distribution curves of both types of lamps and
compare them for your situation. The AR111 design can, in general, produce
a higher internsity and narrower beam than can an MR16. That's because of
the larger reflector in the AR111 which also is made in higher wattages.
One other advantage is that the AR111 has a cap over the filament tube so
that glare and stray light are minimized -- nice if you're mounting the
lamps on the ceiling and people walk into the beam.
However, the MR16 lamp is physically smaller and is available in dichroic
designs that reduce the heat in the beam. Standard fixtures can also
minimize glare and stray light via louvers.
But the real answer to your question depends upon the size of the glass
display (or objects) and the distance from the lamp to the display. For
optimum results, this is something you really need to evaluate visually
several different types of lamps.
There's an analytical approach too. Downlod a copy of the GE "Light Beams"
software from the GE Lighting web site. It compares the illumination,
intensity, etc. for various types of reflector lamps for a given geometry
that you specify.
>Should I be concerned about UV emissions? No. Two reasons: (1) glass
>objects are not normally sensitive to UV (2) there is little/no UV from
>MR16 lamps. I haven't seen any UV data for AR111 lamps, but since all of
>the light comes off the metal reflector, it should be minimal. A clear
>glass lens in front of the lamp or the more expensive "UV filter" lenses
>that fixture manufacturers provide can be used, of course, but I think
>that's overkill.
> Are multi-faceted points better than single point sources? That's a
> matter of opinion. What do you want the objects to look like? One
> approach would be dramatic black background with the objects shimmering in
> front. A second approach might involve a lighter background, multiple
> beams coming from different directions so as to reflect highlights from
> the objects as people move around the display. There's also the "key and
> fill" approach. Bathe the objects in an overall wash of light using a
> medium reflectance background. Then highlight the objects themselves with
> high intensity beams. Deciding which approach to use for a given object
> and then making it work for best appearance is what lighting design is all
> about in this case.
>What is the best angle to light from (above)? Assuming the glass objects
>are on a horizontal surface. Draw an imaginary line from the objects to
>the ceiling. Then move out from that point locating the lighting fixtures
>so the incoming beam of light hits the objects at an angle of 25-30
>degrees from the vertical line.
>Thanks for any input
>
> Jim Miller
>
Terry McGowan
Adam Aglionby
Is it art glass as in stained glass window or objects?
Is the glass painted , inherently stained or dichroic?
More information will hopefully yield more answers.
Remember you get MR series lamps down to MR8...
Adam
Thomas Paterson
Jim Miller wrote:
To maximize both sparkle and the ability to photograph cut glass
(assuming this is what you have) you generally should use more smaller
sources, suggesting lower wattage MR16s. MR16s come in a range of
qualities and beam distribution is an important factor. Cheaper MR16s
(Sylvania for example) often have a greenish tinge about them and a
less even field. If you're lighting with a long throw or to a small
piece, it is hard to go past the GE 42W 9° and 20W 7° lamps which are
beautifully even and controlled.
Whatever you use, glare control is important. The AR111s have superb
glare control from the front, but there is an annulus of light leakage
about 85° off axis which is really nasty. A simple snoot deals with
this, but left unchecked is quite a big problem.
You'll need to use accessories to slightly diffuse if you use an AR111
because the beams are very uneven. Less important on an object than a
large surface, but still a touch nasty.
Interesting site! http://www.millerlightassoc.com/portfolio.html
Remember also that art pieces will change from time to time, so
flexibility is essential. MR16s give you the widest range of beam and
accessory options, whereas AR-111s are ok, but there is a gap between
the narrows and the wides that can be a real problem.
All the best,
Thomas Paterson
http://www.luxpopuli.com
Thomas Paterson
Jim Miller wrote:
Since we all forgot to address your question of UV, I'll come back to
it.
UV only affects non-stable molecules, generally organic ones such as
paper, canvass, organic dyes, organic bonding agents, plus
non-stabilized plastics. Straight glass will be fine. Tinting of
glass is generally done with metal ligand molecules which are fairly
stable, although some artists do blend in less stable dyes. Sometimes
organic pieces (flowers for example) are set into the glass. In this
case, you need wider advice. UV absorbant glass would have been a good
investment for the art piece.
If the art is of a sufficiently high class, or was bought from a
reputable and significant auction house, there will often be a
certificate of authenticity (along with a bundle of other papers) which
will give you a lot of other information such as materials,
liabilities, insurance conditions. From this you should be able to
establish risk. You may need to write a statement as the lighting
designer as to the UV conditions for the benefit of the client's
insurance company. This can save them big percentages on their
premiums. For a recent design, we submitted an 800 page report on the
lighting conditions.
In general, the UV levels from the premium TH lamps (which generally
include UV coatings on their lamps) are pretty low. If you want to add
an extra barrier layer, a UV filter (Bausch and Lomb for example)
should set you back a few dollars and isn't a bad investment in peace
of mind. Actually, it contributes almost nothing with a good lamp, but
it can't hurt.
Finally, if there is ANY daylight in the display location, this is
going to provide FAR more UV than the lamps will. This can be
addressed with UV filtering in the window glass (expensive, but
essential in high grade art installations). A cheaper option is a UV
film, but I'd recommend against it - they lose effectivness (and you
can't tell when without a UV meter) and the labor of pealing the glass
to replace it is just NASTY. Don't go there!
The foregoing discussion not withstanding, I don't think you've got any
issue. Reputable lamps are low in UV, glass is very stable. It's
unlikely that the lighting will damage the art.
Regards,
Thomas Paterson
http://www.luxpopuli.com