my ND filters give weird look..

[Zakaree Sandberg]

So when i use my ND's with my older cine lenses
It gives them a really weird look.. almost like IR pollution.. even though i have a IR cut filter in the front..

they look great! when not using the ND filters.. but the ND just kinda sucks some life out of them..

could it be a bad ir cut filter? bad NDs? (Schneider)

 

[Pawel Achtel]

So when i use my ND's with my older cine lenses
It gives them a really weird look.. almost like IR pollution.. even though i have a IR cut filter in the front..

they look great! when not using the ND filters.. but the ND just kinda sucks some life out of them..

could it be a bad ir cut filter? bad NDs? (Schneider)

Details? What lenses, what focal length, aperture? What IR filter are you using? Provide a sample image to demonstrate what "looks great" and what is "weird look".

Some lenses focus IR at a different distance than visible spectrum, causing mushy images with brownish cast.
Lenses with large physical aperture may suffer from filter imperfections, some pretty badly.

I found Pancro NDs nearly perfect without colour cast and filtering the entire spectrum including IR equally. I tested up to ND 2.1. But, still not suitable for some large aperture lenses like, for example, the Leica Apo Telyt R with the large head unit.