Octopuses Are Colorblind. Here’s How They See the World

https://www.scientificamerican.com/article/octopuses-are-colorblind-heres-how-they-see-the-world/

This article does not explain how octopuses actually match the color in their backgrounds. I like to believe that there are organs in the skin, as yet to be discovered. National Geographic has a good article:

Ramirez and Oakley showed that the octopus's skin also contains opsin, but not in the chromatophores. Instead, its opsins reside in small hair-like structures called cilia. People used to think that the octopus used these cilia as organs of touch; they still could be, but they might also detect light too.May 20, 2015

Octopuses, and Maybe Squid, Can Sense Light With Their Skin