How can I tell if a liquid is (not) emitting light? I found an image of Nuka Cola Quantim, a soft drink from the Fallout video game series, which depicts the bottle as glowing, but it doesn't feel quite real:



Then I also saw this video of a chemiluminescent reaction of luminol:

https://youtu.be/TJj7t2mrpxc

Experienced chemists and/or photo editors might tell right away which is real and which is fake. What hints should I look for when determining if a liquid itself is glowing or is being lit by a different light source?
In a photograph, a light source is always brighter than any surface it is illuminating.

Therefore, if the liquid is the actual light source, the liquid should be significantly brighter than the rest of the bottle. See for example this picture by David Mülheims CC BY-SA 2.5, via Wikimedia Commons:



In the given picture, however, the parts above and below the water level have a similar brightness.