Mimmicking octaboxlight with strobe and bathing curtain

[soeren]

Hi Guys
In a strobist book I saw a pic lightened with a big octabox and it gave me an idea for some protraits Id like to do. Problem is lack of lighting equibment, I have only a single SB26 strobe. Id like to put a bathing curtain in front and above my subjects and shoot the strobe through that from a distance. Trouble is Im loosing a lot of light since I have to put it about 2,5m from the curtain to get the area big enough. Id be using Ektachrome 100G and I am currently limited to f/5,6. Ideas, comments?
Best regards
Søren

[cjbroadbent]

If you can't get a roll of frost, maybe 3ft of Bemberg (used for lining jackets) will do. Anything plastic has colour casts. Open the bottom of a 3ft cardboard box. Tape on the diffuser. Put 2 diagonal stick the other end for rigidity and tape the flash to the sticks.
Or invest in an umbrella and a Manfrotto adapter.

[soeren]

Thanks Christopher.
Tried some shots with a DP&S and the colour cast from the Diffuser is minor but youre right its there. Seems Ill have to go shopping for something better suited and a big box. Will silver lining in the box be recommendable?
Best regards
Søren

[cjbroadbent]

...Will silver lining in the box be recommendable?...
I glue kitchen aluminium wrap inside my boxes but it doesn't give more light - just a little less concentration. Inside a box, the sides are not on the correct angle of incidence anyway.