I have just started to use Graduated ND filters and I have notice that they are not neutral, there give a cross colour which is distinctively pink. If I set my white balance to compensate for this the lower Half go,s green.
Can anyone tell me what is going on here or is this the payoff of using ND filters?
Usually you only get a colour cast with the more budget end of the filter market but you can also get it when you stack more than one filter infront of another , if you can tell us what make of filter you're using and how you're using them we may be able to help a bit more .
The other way of dealing with colour cast is in PP rather than adjusting your white balance , most image editing programs should have some kind of correction option .
I think unless you use the best quality glass filters you always run the risk of colour cast when you stack them but I'm quite surprised you still have a problem with the Hitech if you're using it on it's own .