Hey everybody, I'm currently in the planning phase for a very minor project - shot on 16mm, half of it will consist of daylight exteriors, and the other half will be nighttime exteriors. There's a lot of surreal themes, so I've been trying to find different ways to convey this - and I stumbled across an old video recently from KINETEK (Matthew Rosen) showcasing different ways to apply filters to darken blue skies.
In particular his examples of his work using double 85 filters really caught my eye, and it was something I had never heard of before - and aside from a few brief mentions elsewhere on these forums I couldn't really track down another source of information for this and it leads to a lot of questions I'd have before testing it for myself.
Does doubling up with 85 filters on tungsten stock lead to this much additional warmth as a general rule? And would anything be lost color-wise from correcting it back to a neutral balance in post? It's hard to tell because a lot of the example work is post grading, and has a very stylized look to it.
I'm also a bit confused on exactly how much each of these filters cuts light down from the sky, and if you still have to deal with an overall filter factor as it's said that since the filter is mostly blocking this blue wavelength of light and allowing most of the warmer wavelengths of light through, it's able to darken the sky and equalize the exposure between the sky and subject - but on a sunny day isn't everything being lit by this same blue wavelength of light? Or am I misunderstanding the concept entirely? All of the 85 Filters I'm looking at have a 0.6 Filter factor, so would I truly be opening up 1.3 stops and then getting this effect? Or am I ignoring the filter factor to a degree as that's what's cutting the blue sky?
And as a very quick final question is there any extreme difference in performance between the traditional matte box 85 filters and the circular lens mounted ones?
Any help/examples and resources on this topic would be much appreciated. A lot of this information has become incredibly hard to look for on the internet. Hopefully soon I can just bite the bullet and do a complete round of testing myself, but gathering as much info as I can before hand could save me a lot of money/time.