I was in a situation the other day where I wanted to shoot some stuff in colour, but there were so many light sources of different temperatures that I ended up doing everything in B&W. The complexity of light temperature and balancing this intimidates me. How do I control this as best as I can? Well for now I have made up some sort idea of how to do it, put together from variuos sources on the interwebs, these are quite scarce for film photography. I'll try to put up a case here now and hopefully somebody can chime in on what's wrong or what could be done better. Alright, the setup is as follows, I'm in a location doing a portrait session, I have late afternoon sun (i.e far from 5500 K) coming in from one wall with huge windows. I'm shooting reala so it's still isn't enough, even with reflectors, and the lighting gets pretty dull with only one dominant source. I have to use artificial lights. I choose flash over tungsten due to portability. I have an old colormeter, gossen sixticolor, which can show me what seems to be called LB, i.e. R-B differences, I get the ambient light temperatures, but not the magenta-green color balance. Could I still use it to help me get the right gel for the flash and the right filter for the camera? I often want a colder tone on my images, towards the blueish cyan end of the spectrum, not so much that it is distracting, but not really the typical 'warm' portrait WB you usually see. How can I choose filters that give me a bit colder tones? Do I really need magenta-green balance to do colour balancing? Okay, so I get the temps in kelvin or filter needed for camera in gossens R-B scale, but how do I transfer those reading to the semi-bizarre scales used by gel manufactures? Camera filters are usually quite easy to find mired values for (not a typical good way of handling filters, mired, it's like kinda difficult, must make an app for my phone), but lightning gels use CTO and CTB in different values, and I can't find mired specs for them. And with fluoruscent it's even harder, since I haven't got any way of measuring green, would it work to chimp with a digital camera? Or are their sensors too different from how film handles light spectrums? I have quite a lot of CC gels for enlarging, can these cc values be converted to mired in some way? Since they are in 5cc increments they should be pretty neat to use. Thankful for hints and pointers.