Testing for reciprocity shift

[geoffrey_swenson]

Could one of you tell me what is the best and easiest (fewest pieces

of film) way to conduct an exposure test to get modified exposure

values for a film in ½ step increments. For example with RVP 50,

when I arrive to a 8 sec. exposure I know that I have to expose for

11 sec. and for a 12 sec. reading have to expose for 17 sec., etc.

 

I�d like to determine all the settings between a few seconds up to 4

minutes. Has anyone done this for E100VS and/or the new F100 Velvia?

 

Thank you for all of your inputs.

 

G.S.

[Troll]

Contact the manufacturer

[geoffrey_swenson]

We all know that is pretty useless.

Very often film manufacturers say that exposure over a minute is not recommended. Conversely, some of us know that multi-minutes exposures are possible with excellent results.

[ed_ogrady]

G.S., if you are using conventional film holders you can pull the dark slide in 1" or so increments and make multiple exposures on a single sheet of film.

[geoffrey_swenson]

Thank you Ed. I meant to do it w/ the dark slide, but I wonder if any of you have proven methods, as I would have to vary to light intensity to get readings between 4 seconds and four (or more) minutes.

 

How would you go about it if you did it for yourself? Did anybody perform a test like this? And how?

 

Thank again, G S.

[rainer_viertlb_ck]

i dont know how good my tests have been made, but i made some here....

http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=005lJE