Lighting is important for actual image making itself, but what about the rest of the process? For the final images to look right, all the pieces of the process must be tailored to match what the camera's seeing. I'm going to look at various aspects of the end-to-end process and illustrate why the lighting of each part is important to pay attention to throughout the sequence.
Makeup and Prep Area
In the makeup and prep area, ensure that the lighting you are using matches the photographic lighting on set. Pigments in makeup, fabric dyes, paints and even things like plastics can colour shift, sometimes very strongly, under different colour temperatures of light, whether the camera is white-balanced or not.
Ensure your model or makeup artist is seeing the same colours as you will in the finished product by using bulbs matching the colour temperature of your light sources. This is especially important if doing something colour-critical, like catalogue shoots or anything involving a specific corporate Pantone colour.
If you're using strobes for your shoots, this will be the colour of the phosphor-coated xenon discharge tube, identical to neutral midday sunlight at around 5400-5600K. Therefore, I recommend using 5500K fluorescent tubes in your makeup and prep area if you want to match strobes. These are becoming easier to find, and will work perfectly for this task.
If you're using tungsten continuous lights to shoot with, this can vary between around 2500-3500K or so, depending on the power of the lamp. "Daylight" balanced tungstens are around 4800K. If your tungsten photo lights are on a dimmer, the colour temperature will reduce as the current supplied to them falls. Tungsten can be tricky. If this is your shooting setup, you'll want to find a tungsten light source that matches. However, I would avoid regular lightbulbs. Buy higher-end bulbs used for industrial lighting if possible.
Full-spectrum fluorescent (FSF) fixtures (like KinoFlo lights) generally operate in the warm white to cool white range, around 4800K to 6900K, depending on the tubes you use in them. My FSF tubes are 5900K, and when using those to shoot, I have 5900K 23W compact fluorescent light bulbs (CFLs) in the prep area.
In the Studio
In the studio, ideally you'll have the same lighting as your prep area. This will make it easy for quick changes and touching up makeup on the set.
However, it's helpful to have a lighting solution that can be dimmed. This way the ambient can be dialed down while shooting to allow your modeling/continuous lights to take over. Then it can be brought back up between shots to avoid tripping over cables and apple boxes!
Check for the Ability to Dim the Lights
Bear in mind that a fairly large proportion of compact fluorescent lights can't be dimmed, so you'll have to hunt down the ones that can be dimmed and are the correct colour temperature.
Dimmable ballasts are available for strip lighting, but they're generally not cheap. Fluorescent lights also have a tendency to have colour balance drifts when dimmed, so it would be better to have a "bright" circuit and a "dim" circuit, with a double wall switch.
Alternatively, if you have the money, try LED lighting. It's very energy-efficient, available in a variety of colour temperatures, light outputs and bulb shapes, and can easily be dimmed because it uses DC power. Check the Colour Rendering Index values, and only use LED lights if they're 90CRI or above. LED lighting is still a young technology, so this kind of setup would not be cheap.
For post-production, broad, strong lighting isn't much help. The most accurate colours and contrast come from a monitor which should be the primary light source in the room, so you want quite low ambient lighting.
A couple of 9-14W daylight CFLs, appropriately flagged or shaded to light the room (but not the monitor screen) would be good. It would probably be ideal if you could put these behind the monitor and out of immediate view, somewhere they can still add ambient light to the room.
In the very beginnings of the digital processing, photographers went with the darkroom approach and did their photoshopping with all the lights out. While this works, it was found over time that this causes a lot of eye strain and discomfort for some people.
Other Office Work
Now my office is in the studio, I have three 23W CFL lamps nearby as well as the tungsten ceiling fixture, for other office uses like paperwork, or for non-colour-critical work, to avoid eye fatigue. This brighter daylight-balanced light, I've found, also helps to keep you awake on late nights in Photoshop! For me, tungsten is too warm and cosy a colour to maintain alertness.
Mind Your Lights
I hope this quick look has got you thinking about how to improve your overall workflow, particularly if you're looking towards printed or other colour-critical work. The rabbit hole when it comes to lighting can go about as deep as you like, but I think this should be enough information to make a strong start on adjusting your colour balances from start to finish for the best final product.
Questions? Comments? Hit up the comments below!