window covering for darkrooms: opaque or not?

David Lyga · Aug 4, 2013

I inquired at an art supply store about finding flexible, rolled material that was opaque. I was told that 'opaque' is not really absolute here and that under strong sunlight it would slightly 'glow' if used on my window to block out sunlight.

Seems it is difficult to find a TRULY opaque material unless one buys dedicated 'darkroom cloth'. Are there suggestions to counter this dilemma? I have one: heavy duty aluminum foil as a cost effective solution. Are there others? Please understand that standard poster board will ALSO glow on the inner side if direct sunlight hits it. - David Lyga

Steve Smith · Aug 4, 2013

Aluminium foil would be good.

Darkroom cloth (if it exists as such) should be doubled up so if there is a tiny pinhole in the first piece it will be covered by the second.

Steve.

Paul Glover · Aug 4, 2013

The stuff I found is "Roc-Lon Budget Blackout". When I bought mine it was about $3.50/yard on half price special at Jo-Ann Fabric. I think a few other places carry it too. It's designed for use as a blackout liner for drapes, and from what I've seen so far it's 100% opaque. The way my office window faces (due east) does mean that direct sunlight isn't usually a major issue, so it's always possible it'll pass a very small amount of light.

Steve Smith · Aug 4, 2013

Passing a very small amount of light is probably not a problem. I have never had a 100% lightproof darkroom.

I only use mine for prints though. For negatives it would need to be very lightproof.

Steve.

frotog · Aug 4, 2013

Home Depot sells butyl rubber tarps in the painting section. They are 4' x 15' and sell for about $15 per tarp. I use them in my studio to black out the windows when shooting tabletop stuff. They are light proof and leak resistant. A brass grommet placed along the edge every two feet makes putting them up and taking them down a cinch.

ParkerSmithPhoto · Aug 4, 2013

Go to Home Depot and get the thick black vinyl sold as painter's tarp or vapor barrier for crawl spaces. Two layers of that will work perfectly. This is what I used for the three rather large windows in my basement. Never had a problem.

wildbill · Aug 4, 2013

in the film industry we use blackout paper in rolls with looks like heavy construction paper. I use duvetyne aka commando cloth but you'll still likely need two layers. Black ripstop is available at most fabric stores but you'll need multiple layers as well. Aluminum foil will make everyone think you're a "tweaker".

clayne · Aug 4, 2013

Commando cloth is what I use. Unless you're covering a massive window it's not incredibly expensive or anything. Freestyle sells it last I checked.

Steve Smith · Aug 4, 2013

As an aside, over here when roadworks require roadsigns to be covered up (e.g. no right turn, or no entry signs) the roadworkers use black plastic bin bags to cover them up.

They finish work for the day then it gets dark and the illuminated signs light up and show up through the black bags as if they weren't there!

Often things which you think are opaque are anything but.

Steve.

paul_c5x4 · Aug 4, 2013

Paul Glover said:
The stuff I found is "Roc-Lon Budget Blackout". When I bought mine it was about $3.50/yard on half price special at Jo-Ann Fabric. I think a few other places carry it too. It's designed for use as a blackout liner for drapes, and from what I've seen so far it's 100% opaque.

I don't know what the brand is, but I also use blackout liner to cover the door & window in my darkroom. It is secured to the frame using self adhesive velcro (stitching the stuff puts a neat row of holes in that let light through).

David Brown · Aug 4, 2013

If you are looking for something to put up and take down frequently, then you already have received some good advice. For something more "semi-permanent", here is my variation on aluminum foil:

http://newdr.blogspot.com/2010/05/window-pain.html

PS: It leaks no light!

David Lyga · Aug 5, 2013

Thank you all: this topic comes up periodically and there are always new ways at looking at this problem. - David Lyga

ic-racer · Aug 5, 2013

Related thread with additional information: (there was a url link here which no longer exists)

window covering for darkrooms: opaque or not?

Privacy & Transparency

Privacy & Transparency