I have purchased 2 Cokin P filters ND8 and ND8 Grad, fine on their own but used together a very strong pink tint is visible in the viewfinder, or just with the two filter held together against the light, have emailed the UK importers Intro 2020.co.uk but failed to get a response.
Has anyone had the same experience ? I thought ND was neutral and not supposed to give colour casts
PeteC