I was recently asked about creating or finding a custom lighting effect for my church’s Christmas Eve program. An outline of a cross
was to be projected on stage; I searched a bit on the web but was unable to
find instructions on making DIY filters. I had some ideas of my own and wanted
to test them out.
The filter is a low budget GOBO
filter made from kitchen grade aluminum foil and secured
with kapton tape which is temperature rated for 500F/260C. This can be found
on-line or at some electronics stores.
Step 1: Starting
I did not start completely from scratch; I had a theatrical light fixture as we have about a dozen theatrical lights suspended for the stage. I was able to repurpose one for this effect.
Step 2: Preparation
Removing the lens assembly, I was fortunate to find inner
frame areas to mount onto. I measured the opening and determined a size for the
foil filter, 4” was chosen.
The aluminum foil shape was cut with an X-Acto knife after placing
it on a smooth scrap board. Other cutting techniques such as scarp-booking
stamps should work as well.
Step 3: Mounting
Securing the filter within the fixture was quite simple. As
stated earlier there was a internal ring frame that I was able to affix
to. Using only four pieces of tape ¼” in
length provided adequate security for the lightweight filter. Remember, the
filter MUST be mounted upside down as the image is inverted by the lenses. Also
the fixture used had slide dampers to shape the light, these were used to
reduce the amount of light getting to filter and provide more of a heat block.
I slide in dampers till they just reached the outline of the filter with the
Step 4: Results
The result was used to shine on an empty throne (chair) and
though it was only panned in for a minute at a key moment during a particular
song it had the desired effect.
No color filter was added though that would of course be simple.
Step 5: Other Complexities
The lighting bar in the church was mounted too close to
stage to focus the light fixture by normal means of the lens screw in the
provided slot. I had to extend the lens
assembly further and secure with duct tape and a safety string to the set
Step 6: Costs
- A 1000ft roll of Reynolds Wrap runs ~$25.00, I used 4”
$0.01 (rounded up)
- 100ft roll of 1” Kapton Tape $9, I used 1”
$0.01 (rounded up)
- Total $0.02
- Time to size & cut and mount filter, about 90min (/w
- Time for removing/replacing fixture, about 45min (/w ladder
- Labor cost 2.25hrs * $0.00 = $0.00 (as this is volunteer
Hope this helps others with filter needs for a bargain.