Kirchhoff's law of thermal radiation

The infrared video is of 3 identical stainless steel containers with a small hole drilled into the top of each one. The container on the right is filled with cold water, the container on the left is filled with hot water and the container in the center is not filled, (it is just at ambient room temperature). The lids with the holes are placed on top and you can see that the cavity that is created by the hole on the cold container looks “Cold”, the cavity on the hot container looks “Hot” and the container in the center looks the same as the cavity because, at ambient, both radiation and reflection are the same.