Light proof fabric by the yard?

[GSX4]

I use a combination of two materials.... Thorlabs BK-5 and a silverized and waterproof taffeta from Wilderness Outfitters. Together, they are super light, waterproof, and using the silverized sheet on the outside helps with heat reflection in my wet plate darkbox.

[Dakotah Jackson]

If you have windows you might consider Gatorfoam. You can cut to size and pressure fit into a window well or frame. Great for blocking light. If you take a cement trowel an drill two holes in it and put a backing piece on the other side you have a handle to install and remove it easily without tearing out small holes. Put Velcro strips on the backside as well as on the ceiling and you can just pop it onto the ceiling and it is stored out of the way when you would like window light to come in.

The stuff lasts a long time and is stiff and durable. Just one option in the darkroom.

Per Ctein and a few others, if you put plastic wrap on a wall in the darkroom it will attract the dust which sticks to it. Every week or few you wipe it off with a damp cloth. Helps a lot in keeping things clean and dust free. Have tried it in conjunction with turning on a HEPA filte a half hour before a darkroom session and banished most of my dust related problems. Not easy to do on a farm with all the dirt roads and fields we have - but it works well.

[pbryld]

Thanks for all yours suggestions! There are definitely different options to consider.

[John Koehrer]

I would like to make some drapes for a darkroom, some dark cloths and possibly a very large cloth for a dark box.

What material should I be looking for?
Where can I buy it on the internet (by the yard (if that's how you say it English))?

Thanks in advance.

"By the yard" is correct. Maybe it's "by the metre" in Europe.
It's length will be the length you need X whatever the width it's made in. Here a lot of fabric is 54" wide so one yard would be 36"X54"