Flash Pictures too Warm?

I'm new to flash photography. I recently bought a Vivitar DF 383 to use with my Nikon D700. I use the built in diffuser a lot to soften harsh shadows, with a shutter speed of 1/60 and f stop between 5.6 and 8 depending on the desired depth of field. I've noticed that many of my photos (especially those taking in large rooms) have an orange cast to them. Any ideas why this is, and how I can correct the problem?

Do you set the white balance to flash? If so the room light may be warming up the picture. You could add a piece of gel filter to the flash so it is warmer (balancing the flash to the available light is an old trick), and then set the camera white balance to tungsten.

You're getting a mix of flash and ambient light. Your camera's auto wb can't deal with that and does what most nikons do indoors, get it too warm and therefore somewhat orange.

Fortunately your D700 features some fine WB finetuning controls, use those to dial in a bias of a few hunderd degrees more warm.

Personally I don't quite understand why on such a fine camera you're not using a dedicated flash such as a sb-700

No need to use (& fork out the cost of) a dedicated Nikon flash like a SB700. Vivitar or any manual flash will do fine.

Shooting at 1/60 you are including the ambient light in the shot, which means that you will have mixed light sources - flash + whatever the room is lit with. Auto WB will not cope with that, because the flash is only lighting up a small part of the room & the dominant colour temp will be the room lights.

You have 3 choices -
- switch the rooms lights off & shoot flash only (generally not practical!)
- switch WB to tungsten (if incandescent lights) or fluorescent (if fluorescent lights) and then gel the flash to match - that way all light sources will be near enough the right colour temp.
- shoot at or near the max sync speed (1/250 for D700) & kill the ambient light. You'll then get a black b/g though, which may not be desirable.

As mentioned, you are getting results with included mixed lighting, ambient incandescent light in the background and your subject being white balanced for flash.

Here is a link that will help you more fully understand using electronic flash

http://strobist.blogspot.com/