Thorlabs Light Tight Cloth

As mentioned before we’re still working on a darkbox. We went looking for a cloth that we could use that was light tight and we found it. It’s extremely light and extremely light tight. Available in all different sizes and thought I’d share for those looking for a good cloth.

I plan to make a new dark cloth for using with my camera as my current one sucks pretty bad. I intend to sew it unto a white more heavy cloth so that it doesn’t get needlessly hot when working in the sun.

Link to Thorlabs (you need to look at the BK5 if I’m not wrong).


  1. I checked my Thorlabs BK-5 with a bright LED flashlight and it is not 100% light tight. This was also pointed out by Joe Smiegel on I now use a layer of BK-5 and a layer of silverized taffeta available from this store:- (second fabric from the bottom) It’s also very lightweight, and not 100% lighttight on its own, but combined with Thorlabs BK-5, it is.

    1. Hi Andrew,

      Thank you for your comment on the cloth. I haven’t tried it out using a bright LED flash light but when working with it outside I did not notice any leaking. I wasn’t out in direct sunlight so I might notice something there but for such a thin cloth I found it to be extremely light tight, although perhaps not 100%. So far it works as I want it to; no fogging on the plates.

      Thanks for the heads-up on the silvered taffeta, that’ll come in handy when summer hits our place again!


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.