Experimental use of Biotar 2/25mm

[pluton]

That doesn't make Gaffer tape light proof Frank 

I don't know if the European terminology is different than for North America, but in the example photo that Frank posted, the construction appeared to have been fastened with Duct Tape.
Gaffer Tape is a thicker, more opaque product, though lightfastness is not in the official specs for either.

[Erik Lund]

Same same quote from wiki;
Duct tape or duck tape is cloth- or scrim-backed pressure-sensitive tape - often coated with polyethylene. There are a variety of constructions using different backings and adhesives. One variation is gaffer tape - ........

[Frank Fremerey]

Erik:

Penguins don't vomit in the Sahara desert
and sheep don't mourn your stolen property
and Frank did not know Dadaism is so popular in Denmark
or as Cato used to say "duck tape lets the sunshine in"

[Akira]

Frank, looks nice.  You would need more extension, though,,,

[Erik Lund]

Erik:

Penguins don't vomit in the Sahara desert
and sheep don't mourn your stolen property
and Frank did not know Dadaism is so popular in Denmark
or as Cato used to say "duck tape lets the sunshine in"

Why are you so hostile? I just pointed out a mere fact to warn people here on the site