Most reefers know this and a few just refuse to listen and learn. Lighting is everything when it comes to coral color, or the color of anything really.
No two lights, no two screens, and no two tanks are going to be identical.
Corals will look slightly
They look different in each one of our tanks.
Even in each of our frag tanks that all have the same lighting and are connected together.
With so many variables it is physically impossible for us to guarantee an exact color match.
This is why we post aquarium lighting comparisons, with two pictures of the coral under different lighting so you can get an idea to what it will look like in your tank.
The two photos we post look as close as we can get them to the corals in our photo tank under our lights.
We did an experiment under different lighting to prove this.
Same coral just different lighting.
Notice the coral looks very different in every picture.
Also the angle you view the coral can vary the color.
Take a clam for example.
A clam will usually look a completely different color when viewed from the top vs. being viewed from the side.