Aluminum foil tape
Cap mounted to
with 4-40 nut
; Fig. A: Pinhole sunshine
recorder made from a
plastic 35mm film canister.
The blueprint paper is held
in place by a thin strip of
; Fig. B: The film canister
sunshine recorder can be
mounted on a tripod by
boring a ¼" hole in the lid
and securing it to the tripod
screw with a 4-40 nut.
; Fig. C: Sunshine traces
made on the same cloud-free
day by a 35mm film canister
recorder with a 0.5mm pin-
hole and a tea can recorder
with a 1mm pinhole.
opened and the blueprint paper is washed in
water mixed with a few drops of lemon juice
to enhance the color. The sun’s track across
the sky is preserved on the paper as a deep
blue arc. Any interruptions in the arc indicate
when clouds passed in front of the sun.
Photography by Forrest M. Mims III
You can easily transform a plastic 35mm
film canister into a sunshine recorder. Bore a
¼" hole in the side, then place a small square
of aluminum foil tape over the hole, and use
a needle to make a pinhole through the foil.
Roll a 1¾"× 22" piece of blueprint paper into
a cylinder (sensitive surface facing inward)
with a gap somewhat wider than the pinhole,
then insert it into the canister so the pinhole
is centered between the edges of the paper.
Clock-Driven Sunshine Recorder
For best results, hold the paper in place
with a thin strip of masking tape applied to
the upper edge. Be sure to install the blueprint paper indoors to avoid exposing it to UV
from sunlight. Then snap on the lid.
Quartz-controlled analog clocks are available
for as little as $10. You can easily make a sunshine recorder from such a clock. While this
recorder uses a very small sunlight aperture,
it’s not a true imaging pinhole camera, since
the aperture is in motion as it scans a speck
of sunlight across a sheet of blueprint paper.
Your pinhole sunshine recorder is now
ready for use. Simply tape it to a fixed support
so that the pinhole is pointed as described
Start by removing the clock’s housing; then
remove the clock hands by carefully pulling
them straight up from the face of the clock.
Cut a disk of black paper slightly smaller
previously. For even better results, mount it
on a camera tripod. This is easy; bore a ¼"
hole through the canister’s lid, then attach the
lid to the threaded bolt of a tripod with a 4-40
nut. Then load the canister with blueprint
paper and press it down into the lid.
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