pink flash

[robin]

does anyone have the same problem as me.
using flash in doors the whites come out a little bit pink. other colours are ok
i am using built in flash and ex420

[Mike K]

Give us more to go on, what mode does this happen, Auto, P, Manual? Both built in and 420ex? If not auto what was the white balance set for, auto WB, or flash? how far a way is the subject? What is the ambient lighting, incandescdent? Are you using the 420ex aimed directly at the subject or in the bounce mode? Any diffusers?
It sounds (since you didn't show us any examples) like the white balance is off. Try manually setting the WB to flash, for when the ambient lighting is not too bright and the subject is closer (or if your using the stronger 420ex) the light from the flash should predominante.
I am assuming right off the bat that you did not shoot in RAW, otherwise you can set the white balance during conversion. And this is a good suggestion to troubleshoot your situation even if you don't want to shoot in RAW later. Take a similar shot or two in RAW to see if you get the pink cast. Using a RAW shot that appears pink, try the different white balance options to see if one clears up your problem. If none of the manual WB presets work how about the picker, pick on any pixel that is white, gray or black.
Never use the Full Auto mode, at very least use the P mode so you can use flash and exposure compensation. Stick to the 420ex over the built-in flash and use it in the bounce mode. WAY better! consider getting a Stofen Omnibounce or Lumiquest 80/20 diffuser to give a real natural flash portrait look. Basically everyone has great results with the 420ex, if you don't you're probably doing something wrong.
Regards, Mike K