I went to a paint store to get 2 separate gallons of paint. One was for my hardwood floor. The other was for the surrounding walls. It is a small room. The colors I chose was a latex flat White with a tint of pink (a blush) for the walls and ceiling. For the floor, i chose an acryllic latex White with a deeper pink tint. On the display cards, they looked like night and day. When I painted the room, both colors were nearly identical (a disaster). How can one make sure you are getting what you selected and asked for?
Well, what you are seeing here is called metamerization. This is where one color looks different depending on how the light hits it, and what kind of light is hitting it. Sherwin Williams should and most other paint stores should also have a place to test a color sample under different waves of light. This will show you the truer color, just figure out what kind of lighting you have in the room and use that to make your selection.