Public Lab Research note

Prep of canisters for photo strips

by Shannon | August 05, 2012 16:35 05 Aug 16:35 | #3140 | #3140

Before the first H2S photo strip test in Bayou Sauvage (, I had to get canisters ready for use.

Here is a quick run down of the process:

  1. Make sure you have a dark space.

  2. Prep your space to make sure you have everything, once the lights are off and paper pack is open they can't go back on- have scissors, stickers, etc.


  1. After opening paper pack, take out one strip at a time and cut small strip (about 1 inch or so in width). Put the rest of the paper back in the light resistant bag.

  2. Place a sticker on one end, this will help to show the original color of the paper once the strips are fixed after they are exposed.

What the strip looks like inside the canister

  1. Put strip around wall of canister and close the top off.

  2. Once all the strips are in the tubes, sticker the top and you can either number them for correlation with poles there or once you get to the site (both Scott and I decided after doing this that it was a horrible idea, too many mosquitoes to contend with and it was hot to be standing outside any extra time to do that).

A couple of issues that we ran into:

After we shipped the tubes to Providence for processing, the stickers came off, taping over or writing directly on the tube in white out or permanent marker might work better.

I waited to do this until midnight, but started out not blocking out the one window where outside light could get in (although not much as there is a tree in the way and no street lights). I ended up with a few canisters (designated with a check mark) that were done under this condition.

The containers where there was night light

After I finished with those canisters and put the paper back in the light sensitive bag, I reworked the room and put heavy cloth over the window so that there was no light present.

Final note on canister prep- for the second round of testing, we only had clear canisters, black duct tape to darken the sides of the canister seems to work well, but I'm wondering if anyone knows if that is equivalent of the protection that light resistant bags or thick black plastic offers?

Wrapping clear canisters in black duct tape


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