Photos from Limrock Blowing Cave, AL

Mark,
I am not so sure about your camera's features but I imagine it has various flash options that work great for taking photos of the doggies etc outside but hurt you underground. Lots of digitals have the red-eye reduction feature which pulses the flash at low power just before the main flash goes off. This apparently causes pupils in the eyes to dilate enough to reduce red eye. You should probably try to use manual flash settings instead if your camera has that feature. If not - the ability to do 15 second time exposures on a tripod is great! That way you can use external flashes further from the camera that give better results. Use a few slaved flashes further away if you like. Most cave photographers use flashes from the sides to highlight details of formations with subtle shadows from the flashes. You can also light subjects from behind with big flash units if you like achieving this manually with your model or other hidden cavers running the flash unit(s).

Lynn also has some issues with colors due to using different flashes and the light frequencies they give off. Not all digital cameras can adjust "white balance" to compensate for flashes with too much blue (or whatever) color output in them. The higher color temperatures (measured in degrees K) are more blue while lower temperatures are more of a yellow color light output. Xenon flash units output light at 6000K while some flash powders etc output around 4000k or less. These give you more or less blue tint depending on the flash and your camera setting or film type. Film cameras can use different types of film (sensitive to certain color temps) for different flash unit color temperatures. Digital cameras adjust their color sensitivity by white balance adjustment since there is no film in them you can change. Use of flashbulbs and external flash units can be done better if you adjust the white balance of your digital camera to match the color temperature output of the flash source (set to 5000-6000K for strobe flashes and less for other light sources with lower color temps). They say don't mix types of flashes unless they are at the same color temperature or you will have a wierd mix of colors in your photos. As for your inconsistant results - it is possible your external flash or other lights have different color temps than the one in your camera. It is also possible that using "auto" settings for white balance can affect the color of the photo based on what the camera sensors detect. I don't profess to be an expert at all on all of this but two good sources of info are : On Caves and Cameras by Norman Thompson and John Van Swearingen IV, and Images Below by Chris Howes. They are available at the NSS Bookstore and other places. Read up on all that stuff to make sure what I told you is correct before you go back out there! You may be able to find more info on all this stuff on wikipedia as well.

Best of Luck to you!