Here is an easy way to create a 'black box' in which to take photos of fluorescent bacteria under blacklight.

You will need a cardboard box you can cut, scissors or a utility knife, a blacklight (we recommend those with a fluorescent bulb) or a blacklight flashlight and some black cardboard paper or black paint.

1. First, find a box in which your blacklight can rest if you are using a large blacklight. If you have a flashlight, a shoebox or similar will do.

We used a large blacklight, so we chose a box where at least half the light would be in the box, but where the light switch would remain outside the box.

2. ✄ If you are using the large blacklight, cut out an area for the blacklight to rest in on both sides, being careful not to leave too many gaps for the light to come through. You can use tape to cover up any gaps.

3. ✄ Cut a hole on the lid/top of your box. You will be taking your photos through this hole by laying your phone or camera on the lid. The hole does not need to be big, only big enough for your camera to see through. The hole in this box is ~1.5 in diameter.

If you are using a flashlight, you can either shine the light through the hole too, or you can place the flashlight inside the box with your Petri dish. 

4. Place a piece of matte black paper (like cardboard) on the inside bottom of the box. This is where the petri dish will sit so you want to make sure you have a nice non-reflective black background. You can also paint it black if you prefer. 

5. Turn on the blacklight/ flashlight and take your photos! Always remember to turn off your blacklight when you are done.