Long exposures on budget.

[Roman]

I plan to make some shots of the city with the shutter open for minutes.
Becuase I don't want to spend cash on expensive gray filters like High-tech ND 3.0
[this takes 10 stops], I'm looking for DIY ideas.

The first thing I found by myself, is a piece of glass used for the welding helmets.
Even got one actually but the glass is too thick for the Coking P mount. Not to mention it's too narrow as well.

I'm using b&w film so the cast is not an issue for me.

Any help appreciated?
R.

[Vaughn]

Stacked red (25A) filters on slow film? But use a lens hood to minimize flare.

Or even stacked red (or orange) and dark green filters?

While the cast is not important, the relative tonalities of colored objects will change.

Vaughn

[Jim Michael]

I had a welding helmet filter that was about 4x4" I bought several years ago at a welding shop for photographing the Sun.

Some solar filters are made from aluminized mylar. Not sure how many stops that would be, but a lot. May come in various coating strengths for other uses.

Maybe some Lee gels to implement Vaughn's idea.

Two polarlizer gels oriented orthogonally (cross-polarized).

The film they sell for tinting windows.

[Marko]

I plan to make some shots of the city with the shutter open for minutes.
Becuase I don't want to spend cash on expensive gray filters like High-tech ND 3.0
[this takes 10 stops], I'm looking for DIY ideas.

The first thing I found by myself, is a piece of glass used for the welding helmets.
Even got one actually but the glass is too thick for the Coking P mount. Not to mention it's too narrow as well.

I'm using b&w film so the cast is not an issue for me.

Any help appreciated?
R.

You can always get another Cokin holder, they are cheap enough, and file off the separator between the two adjacent grooves to adjust for the thickness.

If it is too narrow, you can make an edge mask out thin plastic or thick paper and add a bit of a cardboard as filler on the sides.

Or you can make a custom holder out of thick paper and/or thin cardboard. Something similar to this.

[Steve M Hostetter]

You might try shooting with paper negs with an iso of 1-2 ?

[Nathan Potter]

You can use some exposed and developed negative material. Hey log 3.0 will get you 10 stops. There will be a bit of image scattering but it'll be minor.

Nate Potter, Austin TX.

[Mark Sawyer]

If you're contact printing or not enlarging much, unscrew the front element and put in a pinhole stop. That gave Weston an eight-hour exposure for still-lifes...

But enlarge it much and the diffraction limit will get you...

[sun of sand]

was going to mention exposed developed film ..works pretty well, tried it.
Lith film/paper in camera easy 4-6 stops put a blue or green filter and maybe 5+/8 stops
maybe those filter factors are wrong with lith film. 5-7 stops
maybe expose/process lith film since it's thinner

[Steve Hamley]

How about crossed polarizers?

Cheers, Steve

[hobbim]

Crossed polarizers or a tightly fit welding glass are the way to go (or stacked NDs). If you go for too many separeted filtes, you'll start getting problems due to the reflections and stray light on the filters.