@ Malcolm J. Rayfield - Well that's a bummer. From what you said, it sounds like Apple would have to add that feature into their iOS to achieve that effect.
I like your thinking-out-of-the-box solution of using a thin colored membrane. I'll definitely explore your suggestion and see if I can make it work. I think theres a photography shop near by as well. What luck!
To anyone who is interested, here are some other suggestions:
-There's an application for desktop and laptop computers called "f.lux" that does exactly what I described.
F.lux is also available for Android phones, but can only be installed on iPhones if they are jail broken.
-Amazon sells orange tinted glasses "Uvex S1933X Skyper Safety Eyewear." I discovered the suggestion on this site https://www.marksdailyapple.com/how-to-conduct-a-personal-experiment-yellow-ligh t-exposure-plus-an-announcement/
-LowBlueLights sells a bunch of solutions for blocking blue light such as screen filters and glases. https://www.lowbluelights.com/index.asp
Unfortunately, all those solutions are either "hardware" solutions, or software solutions that require voiding the warrenty of the iPhone.