How to take exposure readings for shooting with ISO 0 - 1 Tintypes?

[njrfoto]

[h=2]Hi all,[/h]

Just a quick question regarding taking efficient and correct exposure readings for shooting with ISO 0 - 1 for making portraiture tintypes.

I have a Sekonic L-358 meter for my studio portraiture lighting but the Sekonic only goes down to ISO 3, which isnt low enough when the sensitivity of a tintype is ISO 0, or ISO 1 at best, so my question is simple; how can I take precise and useable readings using a meter (or exposure calculator) to get the right exposure settings for my camera and to set the required power output for the lights lighting the sitter?

If any one who has any experience making tintypes in a studio setting, who has already done lots of trials and sussed out the guess work, could send me in the right direction of discovering the best practice of how to get the correct exposure for studio tintype portraiture lighting that would be amazing!

All the best,

Nathan​

 

[480sparky]

Take reading at ISO 3, and increase exposure by 2.67 stops.

 

[Prof_Pixel]

OK - your meter goes down to ISO 3. One stop less (half that) would be 1.5. One more stop less would be 0.75. Take your meter reading at ISO 3 and then open up your lens 2 stops for an ISO of 0.75. (Or 3 stops for an ISO of 0.38.)

BTW, your dark slide would have an ISO of 0

 

[ThePhotoChemist]

Also remember that wet plates are mostly sensitive to blue and UV, therefore meter readings may not be entirely accurate. I've heard of people putting blue gel over the meter sensor to compensate but I've never tried. Honestly, I'd say just shooting a bunch of tests and getting a feel for it will serve you better than relying on a meter.

Luke, turn off your targeting computer...

 

[removed account4]

when i make silver gelatin tintypes or paper negative exposure tests
i put them in a 35mm camera instead of a big negative. its easy to see
even 35mm size if the exposure calculation was off or right on ..

good luck !
john

 

[Andrew O'Neill]

That's like when I'm working with Efke IR and opaque IR filter. My metre also only goes down to 3. So I metre at 3, then increase/add a stop to get down to 1.5, and a stop more to .75.