When shooting the dance floor at a wedding, I want to be able to set up a few off camera flashes. I obviously can't just set up the flashes and shoot since the hall will have different temperature lights than the flash and as I move closer or farther from any given flash the temperature of the light will change and the necessary whit balance will not be consistent. I suppose that what I have to do is take a reading of what temperature the hall lights are and then put gels on the flash to be the same, that way no matter where I shoot in the room the white balance will be consistent. I do not have a light meter and here is one of my questions: 1) Can I just take the white balance reading off of a white piece of paper and then put on the corresponding gel? Another question: 2) How do I know what gel corresponds to a specific colore temperature? Also... 3) Does everything I said make sense? Is there a better way to do this? Thanks!