Wood Frames of ND Gel for Window in BG?

[Rob Davis]

I work on an unscripted show where we primarily shoot exterior interviews but occasionally will move inside and use a window as our background when the weather is bad. I’d like to be able to ND the window to reduce the amount of light needed on talent and am thinking of having a couple of wood frames built out of 1x3 strips of lumber so we could quickly drop in different levels of ND. Being that the window is only a couple feet behind talent (out of focus but barely), is this a good approach or would we see lots of reflections, etc.?

 

We don’t have time to apply the gel directly to the window as the light changes frequently, and don’t have the budget to get hard NDs. I think a large net would be too close and in-focus to disappear completely. We also can’t drop a polarizer for the camera to mitigate reflections because talent always wears sunglasses. The window is always shaded, however, so we’ve had no reflection issues with the glass itself. 

Edited August 9, 2019 by Rob Davis

[Phil Connolly]

If the gels flap about in the frame the are going to draw attention to thereselves. How big are the windows - I guess smaller frames with really tightly stretched gel would be more stable. 

Can you mount the treatment outside? A net could be backed further away from the window so its more out of focus?

 

[Satsuki Murashige]

I would try Rosco Scrim. It doesn't wrinkle or reflect so you can apply it very quickly to the outside of the window frame with just paper tape. Cuts about 2 stops. Try to keep the depth of field shallow, as it will be more visible than directly applied ND gel or acrylic.

[Rob Davis]

The section of the window that appears in the background is only around 4’x6’ and the gel frames would be placed outside, behind the glass. We already have rolls of ND, which is why I was hoping to just stretch it tight across wood frames and staple-gun it. 

[Satsuki Murashige]

I suspect the large gel frames will be susceptible to wind, but if you’ve already got the gel then might as well give it a shot. Please let us know how it goes!

[AJ Young]

Have you tried water and a squeegee? I've heard it actually works.

You spray the ND Gel and window with water, then use the squeegee to apply the gel and remove any bubbles/ripples. (Obviously, you cut the gel to size)

[Rob Davis]

I know the squeegee method works but we would just have to switch them out so frequently, it wouldn’t be practical. If we build the frames I’ll report back as to how well it works. 

[Phil Connolly]

Probably worth trying until the RED cinema "Super Death Battle War Skull Face" 16K camera comes out next year with its 37.5 stops of dynamic range, rendering such things as ND obsolete 

[Rob Davis]

I know the squeegee method works but we would just have to switch them out so frequently, it wouldn’t be practical. If we build the frames I’ll report back as to how well it works. 

[Rob Davis]

2 minutes ago, Phil Connolly said:

Probably worth trying until the RED cinema "Super Death Battle War Skull Face" 16K camera comes out next year with its 37.5 stops of dynamic range, rendering such things as ND obsolete 

Haha. The window rarely clips but that doesn’t mean they’re gonna spend days isolating the subject from the BG in post. We’re shooting 22 episodes.