Why not open feed colored syrup? Nearby hives are likely to pack away open fed syrup, whether it's colored or not.Moral of the story, color your syrup if you want to, but please don't open feed colored syrup.
You may have neighbors that are collecting honey in their hives. If you open feed your hives you may contaminate neighboring hives (and their honey) with syrup. In general unless you have a lot of space I would not recommend open feeding because you do not want to contaminate any hives that are not yours.Why not open feed colored syrup? Nearby hives are likely to pack away open fed syrup, whether it's colored or not.