Homemade diffusors with good transmission properties

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Troels
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Homemade diffusors with good transmission properties

Post by Troels »

Reading in this forum about different ways to diffuse light it seems as if you have to choose between the two main paths:

1) Either you go for the wanted shape and find ping-pong balls, plastic cups, youghurt containers, paper coffee mugs etc. The price is often heavy loss of light and unpredictable color properties.

2) Or you go for the wanted high light transmission and controlled color and use paper tissues wrapped around bent wires or what you have. The advanced variation of this is to use bendable professionel diffusing filters. (As discussed by Pau in another thread today). It is not trivial to get the right shape.

After having filled a drawer and several boxes with white - and almost white - plastic containers I tried to find a way to combine the two strategies.

I discovered that is was much easier to find transparent containers with the right shape than finding any with the right light transmission properties. So the remaining problem was to make the clear plastic diffusing. Why not use our preferred white tissue paper? It turned out to be rather straight-forward. Here is what you need:

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A) Cut the container into the wanted shape. As demonstration I have cut out a part of the neck from a juice bottle. Mount a stick for easier handling (not shown here).
B) Make the outside surface of the diffusor more rough with some sanding and give it a good spray of removable mount glue. Should be done outdoor. Let it dry untill it is not sticky anymore.
C) Wrap pieces of tisssue paper around the surface and press them firmly in place.
D) Cut off the surplus paper not adhering to the surface with a pair of scissors with thin blades. Cut as near the surface as possible. Press again and you get a smooth surface covered with one layer of paper.

Viola, here you are:

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There are some small wrinkles in the paper. I don't think it is a problem.
The following two pictures are taken with just one Jansjo lamp and exposures of 1/10 sec. and 1/4 sec. using theese diffusors.

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I prefer a directional main light, but if you go for an omnidirectional shadowless light you just choose a more globular shape and more lamps.
Now all my white containers are thrown out.

I am tempted to add another idea for those using ping-pong balls.
I discovered that the big energy saving LED bulbs were equipped with a bulb of plastic, not glass. I was possible to cut the top of a non working bulb with a fine toothed saw for metal work. It is somewhat brittle, but can be shaped with some care.

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I have not tested this yet, but there is good reason to suppose, that both light transmission and colors are better optimized than in the youghurt containers and ping-pong balls.
Troels Holm, biologist (retired), environmentalist, amateur photographer.
Visit my Flickr albums

zzffnn
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Post by zzffnn »

^ Very nice, thank you for sharing.

Assuming shape and size of the LED diffuser is perfect, do you prefer glued-on paper or LED diffuser?

Rust-Oleum and Krylon make frosted glass spray. Have you tried those? I have not done macro with those, but the Rust-Oleum that I have seems decent, as long as I spray it on evenly.

Troels
Posts: 600
Joined: Mon Feb 15, 2016 11:06 am
Location: Denmark, Engesvang
Contact:

Post by Troels »

zzffnn,

As a starting point I have preferred the glued paper because the thin, transparent plastic is easier to shape and cut.

I have never heard of frosted glass spray. Sounds very interesting and even easier.
Troels Holm, biologist (retired), environmentalist, amateur photographer.
Visit my Flickr albums

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