A shadow wall, also known as a Silhouette Wall, is a phosphorescent
wall used with a timed light source to capture and display
Children pose in front of the wall while a light flashes creating a
black shadow on a green glowing wall. This allows the kids to turn
around and see their shadow. The shadow fades, allowing another
child to take a turn.
Shadow walls are popular in childrens museums and other indoor play
areas. However, they can also be made inexpensively for birthday
This article will give advice for creating each component in a
professional manner and lower cost hobbyist alternatives.
Phosphorescent paint comes in many varieties, most of which are
designed to maintain their glow for a long time. Shadow walls are
unique in that they require a paint that is relatively bright, charges
very quickly, and decays very quickly. To meet these criteria,
Glow Inc. designed a custom mix called the
Shadow Wall Formula. While meeting the above requirements, it
is also designed to resist the damage caused by kids touching it.
It applies easily with nominal smell and no fumes.
You will need 1 quart of Shadow Wall Formula per 4’ x 8’ sheet.
The wall’s structure can be created using sheet materials like
drywall, wood, vinyl, plastic, or glass.
The best materials are clear, such as glass or clear acrylic (Plexi-glass).
If using glass, make sure that it is thick enough that it can not be
broken by excited children. Clear acrylic is a lower cost, easier
to use material. However, clear acrylic scratches easy and
requires some maintenance.
For clear wall materials, we suggest you paint the rear side of the
clear sheet with several layers of Shadow Wall Formula and then a layer
of standard acrylic fluorescent white paint. Allow to dry between
layers. Then hang or glue the glass to the wall with the painted
side facing the wall. While costly, this creates a very smooth,
For opaque materials like wood, vinyl, plastic, and drywall, prepare
and prime the surface as you would for any other water-based paint.
Add a several layers of Shadow Wall Formula, allowing it to dry between
For a cheaper alternative, my personal preference is corrugated
plastic (Coroplast). It can be acquired at most sign shops for
under $20 for a 4’x8’ sheet. If you go this route, get white and
do not prime it before adding the glow paint. It can be cut into
manageable sheets for storage and weighs very little, making it ideal
for temporary installations like parties.
A common mistake is to have too much ambient light in the room.
If you want a bright shadow wall and high contrast shadows, then you
need to keep the room just above pitch dark. The room would
ideally be painted flat black and no light source would directly shine
on the shadow wall. This includes light from other rooms when the
door or curtain is open.
Red light will increase the discharge speed of glow pigments used in
the Shadow Wall Formula. This can be used to your advantage in
professional installations to provide light for entrance and exit while
also quickly clearing the wall for the next child. While any red
light will work, I personally suggest red LED par cans.
Children waiting in the queue should be in a dimly lit room so their
eyes have a chance to dark adjust, preferably for 5 or more minutes.
The light to charge the shadow wall should emit as much ultra-violet
light as possible, preferably with nominal visible light.
Visible light adjusts the children’s eyes for daylight and the glow
will therefore appear less bright.
That being said, disposable cameras with flash are an effective
charging light for shadow walls used at kid’s birthday parties.
They can typically be acquired for free by asking nicely anywhere that
processes film. Strobe lights are another inexpensive alternative.
If you use these visible light alternatives, consider telling the
children to close their eyes for the flash.
For professional installations, use only ultra violet lights, also
known as black lights. For crisp edges on your shadows, use a
light with a single point of origin like a bulb. Tube or LED black
lights have a wider origin, which will blur the edges of the shadow.
Black light bulbs sold for parties that look similar to regular screw-in
light bulbs perform very poorly.
Therefore, I suggest a high powered “cannon” or stage fixture like
Chauvet’s Black Shadow 400w Blacklight. You can use the light’s
spec sheet to determine its beam angle. With this angle, you can
determine how far back to mount the light for optimum performance.
I suggest you mount the light 1-2 feet from the floor. This low
aspect will make most shadows taller than the children while keeping
their feet in frame.
Using your timer, adjust the “flash” time for optimum performance.
Longer flashes create a brighter glow. However, longer flashes
also blur the edges of the shadow as children move.
For home use, the timer is a human pushing a button.
For professional installations, you will definitely want to add an
automated timer. This can be accomplished hundreds of ways.
I personally use a computer, Enttec DMX USB Pro, Chauvet DMX-4
Relay/Dimmer, and Vixen software.
Here is a typical Timer sequence started by human trigger:
00.0s Countdown clock 5
01.0s Countdown clock 4
02.0s Countdown clock 3
03.0s Countdown clock 2
04.0s Countdown clock 1
04.9s Red light turns off
05.0s Ultraviolet light turns on
05.5s Ultraviolet light turns off
(Note: this is when the wall glows)
30.0s Red light turns on
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