| INSIDE
USE:
The 1/4 Dome and 1/2
dome mirrors are for inside use. They can be used outside in a
protected area however, they SHOULD NOT be in the open exposed to all
weather. Neither of these mirror have sealed lenses and the mirrored
backing may eventually detach from the lens. The steel backed full
dome can be used outside however it is not recommended. Excess water
leakage through the hanging bracket rivet holes could eventually fill
the dome with water. We have never seen this happen but it is
possible. If you are in a dry area or you can add a protective cover
over the top of the mirror then it should last for a long
time.
Viewing Distance:
The
distance you can see objects in a dome mirror is much different than
the round convex mirrors. Objects seem much smaller because of the
wide area a dome mirror will reflect. When sizing dome mirrors you
should base your viewing distance on 1/2 the size. For example,
a 12" 1/4 dome is actually only 6" tall. So the effective
viewing distance (the distance you are standing from the mirror when
looking at it) would be 6 feet. An 18" dome should be used when
you are at a distance of around 9 feet etc..
The effective
reflective distance for dome mirrors is around 25 feet. If you need to
clearly see objects farther than 25 feet I would not suggest using a
dome mirror. You should consider a round or rountangular convex
mirror. Generally speaking, dome mirrors should be used to see wide
areas where the maximum distance your wanting to view is around 25 to
30 feet or less. Dome mirrors work well in hallways and smaller areas
where the objects are going to be relatively close (10 to 20 feet) to
the mirror. As an added note: Technically the reflected distance is
infinite. The problem is that distant objects are so small that you
will not be able to reliably recognize them. These numbers are,
however, variable. Standing close to a 26 (13" tall) dome mirror
will allow you to see objects farther away then if standing the same
distance from a 12" (6" tall) mirror. The reason is because
as the dome gets larger, the mirrored lens has less curvature. Objects
appear larger in larger mirrors. In order to determine the size dome
mirror you should use, 1st consider how far form the mirror you will
normally be standing. If you would normally look at the mirror from 10
feet, then you could use an 18" (9" tall) or a 26"
(13" tall) mirror. Next consider how far away from the mirror
objects will be that you need to see or watch. If the objects (for
example a doorway or entrance area) is around 20 feet, then the
18" mirror would be fine. If the objects or area are 25 to 30
feet away, then you should go to the larger size. In this example that
would be a 26" dome. If the size of the dome mirror is not a
concern and you really need to clearly see an area, step up to the
next larger size.. in this example that would be a 32" dome
mirror.
1/4 Dome Mirrors: (Web
Page)
The 1/4 dome mirrors
are used for "L" intersecting hallways or corners of a room.
When placed in a corner, you can see an entire room by looking at the
mirror. This is good for an office to be used when your back is turned
toward the door. Often times when your working on your computer. A
quick glance at the mirror will allow you to see if anyone is walking
into your office. In a hallway, you can see around a corner to avoid
others walking from the opposite direction.
There are "lens
only", "hardboard back" and "steel back"
versions available. The hardboard backing and steel backing have
hangers attached to the backing which make the mirror easy to install.
We do not suggest getting the "lens-only" 1/4 domes unless
you have a specific need for only the lens. There is a 3/4"
flange around the top front of the 1/4 dome which can be used to hang
the mirror. You will need to gently drill two holes (one about 1"
from each end) in the flange to hold the dome against the ceiling. A
"lens-only" dome is sometimes the best choice however the
person doing the hanging should be careful when drilling the holes in
the flange. They should also be careful not tighten the screws to
tight or the flange will crack. In most cases the hardboard back is
what you need. In some cases, as in the food industry, the steel back
may be preferred. Not because of its strength, but because because
hardboard is a wood product and not suitable for some
areas.
1/2 Dome Mirrors: (Web
Page)
The 1/2 Dome mirrors
are mostly used at "T" intersecting hallways. They may also
be used on any flat wall where there is no corner to mount a mirror.
When facing a 1/2 dome, you can see 90 degrees to the left and 90
degrees to the right. Persons coming from either the right or left can
also see 90 degrees and therefore would be able to see you as well.
Placed on a flat wall in a room with cubical offices will allow
persons to see around the office without standing up to look over
their wall. We have seen 1/2 dome mirrors used in many different
places so your not limited to the uses described above. Just
remember, images appear very small in dome mirrors so what your
wanting to see should be rather close. Do not place a dome mirror in a
parking lot expecting to see cars coming from 100 to 200 feet away.
Even something as large as a car will only appear on the mirror in an
area of about the size of a
dime.
The
"Lens-Only" version has no backing and must be fastened to
the wall with glue, double sided tape or by drilling three screw holes
in the flange. One hole in each side and one in the middle of the
flange. A "lens-only" 1/2 dome can be securely mounted
however the person doing the hanging should be careful when drilling
the holes in the flange. They should also be careful not tighten the
screws to tight or the flange will crack. In most cases the hardboard
back is preferred. There are mounting brackets attached to the
hardboard and steel backed mirrors which make the 1/2 dome very easy
to install. As with the 1/4 dome, there is no advantage to getting the
steel backed 1/2 dome unless you can not used wood products in your
area as in the food industry. You may also opt for the steel back if
the area is going to be extreemly humid or wet. The hardboard back is
weatherproof however there is no question that steel will outlast the
hardboard in wet conditions. (Note: Water can accumulate in the bowel
shape of a 1/2 dome mirror so do not allow water to run down into the
mirror. This could damage the
mirror.
Full Dome Mirrors: (Web
Page)
Full dome mirrors are
like cutting a basket ball in half. One half of a basket ball is the
shape of what we call a Full Dome. Full dome mirrors are used where
persons are looking at the mirror from every direction or where there
is no wall to mount a 1/2 or 1/4 dome mirror. For example a four-way
hallway intersection. Full domes are mounted from the ceiling and hang
downward.
There is a flange
around the full dome mirror which may be used to hang the mirror. For
the "lens-only" version you can drill three or four holes
evenly around the flange. The lens can be mounted directly against the
ceiling with screws or you can hook three (or four) chains to the
holes for hanging from a ceiling. The Hardboard or Steel Backed full
dome has three mounting brackets attached to the back so chains can be
fastened to the brackets. The backing will also prevent dirt or dust
from building up inside the bowel shaped mirror. You can also use
mirror mounting brackets to hold the mirror to the ceiling, or screws
running through the rubber rim. There is no standard way of mounting
dome mirrors so one should always use their best judgment for the
application.
Drop-in Full Dome
Mirrors: (Web Page)
When you hade a dropped
or "suspended" ceiling which uses 24" x 24" or
24" x 48" ceiling tiles, you should consider using the
Drop-in dome. The Drop-in dome is a one-piece mirror with the dome
mirror blown from a single 23 7/8" x 23 7/8" square sheet of
acrylic then coated with a mirrored finish. The portion around the
dome mirror is painted white to roughly match a standard white ceiling
tile. The mirrored dome is available is one size 24" (actually 22
1/2"). This is the easiest ceiling dome mirror to install because
all you do is remove a ceiling tile and replace it with the dome
mirror. There is a 48" ceiling tile dome mirror but the mirror is
still only 22 1/2" in diameter. The backing or flange around the
mirror is 23 7/8" x 47 7/8" so it will replace a 2' x 4'
ceiling tile.
See-through Full
Dome Mirrors: (Web Page)
The see-through dome
mirror is like the Drop-in Full dome mirror with two exceptions:
1) The mirrored backing
has the see-through finish so a camera can be placed behind the
mirror.
2) The mirror is
available in two sizes, 18" and 24" (22
1/2).
Smoked Domes - One Piece:
The one piece smoked dome is similar to
the above Drop-in full dome mirrors only it is a smoked finish and can
be used to house a camera.
Smoked Domes - Two Piece: (Web
Page)
These are NOT MIRRORS. They are to be
used to house cameras, or to be used as fake camera housings. There
are three sizes, 9", 12" and 22". The backing plate is
the same for all three styles. The only difference is the size of the
dome and the spacer ring around the dome. Remember when sizing the
dome for a camera, remember the size is the diameter of the top of the
dome. The depth of the dome is 1/2 the diameter so a 9" dome is 4
1/2" deep.
Note about using cameras:
We do not sell or claim to know
technical specs of cameras or their mounting brackets but there are a
few suggestion which may help in an installation.
1) A piece of hardboard (the brown
stuff that pegboard is made from without the holes) cut to the same
size as the backing plate or ceiling tile makes a good mounting
surface for the camera. Once the camera is mounted and is working
without the dome covering it, you can lift the board you've mounted
the camera onto and slide the drop-in dome under it. The hardboard
used to mount the camera will then serve to keep out dust and light as
well as hold the camera.
2) Avoid any lights or sunlight from a
window shinning directly at the dome housing. Light shinning directly
at the dome will shin into the housing and reflect off the camera.
When this happens the camera will be looking at a reflection of itself
on the inside surface of the dome housing. You will also be able to
see the camera through the dome which is typically not something you
want. The best situation is for the lighting to be above the level of
the dome. For example most suspended ceilings have the light recessed
into the ceiling so it would not be a problem. If however the dome is
in front of a window or a spot light is pointing at the dome, you may
have the problems describer above. If this is a situation which can
not be avoided, then you will have to block the light by adding some
black felt inside the dome on the side the light is coming in. Each
situation is a little different so there is no canned method available
to solve this problem. Black (Acrylic) spray paint or silver paint for
the see-through dome can also be used to block light. You need to be
careful not to cover the area where he camera will be looking out. A
piece of paper and painters trim tape can be used to mask off the
camera viewing area. Painters trim tape has a very weak adhesive so
the mirror coating should not be damaged when it is pulled off. Also,
use a light coat of paint. It's always to go over it a second time
then to ruin the mirror finish with a thick coat of
paint.
3) Use a camera capable of picking very
low light. Both the smoked domes and the mirrored see-through domes
only allow about 30 to 40% of the light to pass through to the camera.
A camera made to pick up normal light will not work
well.
If you think of
anything else we should add to this area, please send us an email or
call us. (Contact Us)
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