ND'ing a window

[Mark McCann]

Hey all, ive been looking around for tips to help cutting down the light from a window to no avail ,i gure here would be the best place to get some tips. Ive got a small student shoot in a local bar coming up, low lit interior it has couple windows about the place that i need to prevent blowing out, whats the best way to do this?

 

Is it as simple as cutting a roll of nd to the windows specs and gaffering taping it or attaching it on? would the nd be noticeable within the shot? Are there any good ways to hide it?

 

appreciate any help

 

Mark

[Adrian Sierkowski]

You cut the ND you need, based on how many stops you need to cut down, for example ND 1.2 is 3 stops and I would normally use the flat-sprite squeegee method. Which is, let some sprite go flat in a bucket and use a squeegee to put it on the window, then apply the ND to it. It'll stick and wash free with water later on.

[John Sprung]

ND is also available in rigid plexiglas, about the same thickness as ordinary window glass. Typically, you'd cut it in pieces a little bigger than the window sash, and tape or screw it to the outside. You can put it over an open window, too. We even used to make boxes out of it to go over a door and give the actors room for an entrance.

 

 

 

 

 

-- J.S.

[Nathan Blair]

The best method is definitely the squeegee. If you can't do this because of location restrictions or are instructed to gaff it, just make sure it's very tight and there are no wrinkles that can cause weird reflections, and if it's outdoors sometimes it can blow around and look like some kind of weird alien forcefield has appeared outside the window. I've been on a set where we very cleanly taped gray gaff tape along the rim of the ND to give the illusion that the gaff was part of the window frame.

[Mark McCann]

Hey all, thanks very much for the info, mucho apreciato. Im gonna try the Sprite method tomorrow on a test window and see how it goes, if it goes good ill give the location a shout about doing that hoping they would be okay with it Just checking, when you say sprite you mean the drink yeah?

 

 

thanks

 

Mark

[Adrian Sierkowski]

Yep;

that wonderful lemon-lime nectar of the gods with fizzies ;)

make sure it's flat, though.

[Andy Joesoef]

Would filtering the light source with a diffuser work you think ? One time I had to use an umbrella to take out 2 stops on a lit window and it worked. I guess this is more of an exposure solution rather than to bring image detail.

[John Sprung]

Would filtering the light source with a diffuser work you think ?

 

Sure, provided that you have a big enough net or silk, and a small enough exterior area seen through the window. Bear in mind, too, that the sun will move throughout the day, so that butterfly on high rollers or whatever may need to be tweaked from time to time. The logistics typically favor just ND-ing the window.

[Jaron Berman]

Sounds easy but cutting the gel sucks. Nothing fun or easy. Make sure you have a VERY sharp knife or you'll rip/kink the gel - makes the edges come up prematurely. Home depot sells a "window film application kit" which is meant for their adhesive window things (like fake stained glass) but the kit comes with a sprayer full of application solution, a mini knife and a decent squeegee. And the best part is - home depot is everywhere. Get the window very wet, wet the gel a little too, stick it down and squeegee. Trim the edges to be a tiny amount smaller than the window - like 1/32 or 1/16" and you'll prevent air from getting trapped under the edges and the gel curling when the window changes temperature.

 

Or you can get window treatment thats set-dressed in-shot (blinds, curtains, etc...) - you may be surprised how expensive gelling windows can be.

 

Now, the more important discussion - what's your end goal? There are a couple ways to go about this and both involve knowing how much stop you need. If you're simply trying to balance the window to your indoor exposure you need to figure out how much of your overall exposure is coming from the window first. Also, figure out what kind of lighting you can afford inside - tungsten, hmi/kino, or bounce. If you're using tungsten units, make sure that instead of just ND you get 85ND gels! Then you're working tungsten indoors. If you're spending that kinda money to gel windows, you probably wanna make the most of that effort and use cheap tungsten lighting (and not worry about gelling practicals). It may be cheaper to rent bigger HMI units inside and skip gelling altogether - with good location scouting you can figure out what time of day to avoid so your lighting units will make the most of what you have.

 

Or, go old school and ping-pong where possible - using shiny boards, xenon mirrors and diffusion you can redirect light from outside an off-screen window to where you need it.

 

But before going to any trouble - decide what it is about the window you wanna save - is the action outside important? what time of day is it supposed to be?