In 2018 I had to visit an industrial research facility of a major smartphone manufacturer. To protect their intellectual property, security requested that all visitors and staff have their phone camera lenses covered by a blue sticker which they would apply and subsequently take off when we leave the premises.
These opaque, blue photos were taken with the sticker on my phone. The hue variations were from the automatic white balancing algorithms on my phone desperately trying to find a neutral hue to calibrate against. Artifacts from the JPEG compression are also more readily apparent.
These are the bluest of blues I have ever taken with my phone camera.