Use a wet plate as a meter?

[Marizu]

I’m thinking of trying to make some B-Dags but we have fairly variable weather in the UK at this time of year.

I had wondered whether Dag exposures would be fairly proportional to wet plate ones so if I always exposed a wet plate before exposing a Dag, would I eventually be able to extrapolate Dag exposures from a preliminary wet plate?

There are a number of factors to be considered such as age of collodion and the length of time since sensitisation and colour cycle of the plate, I guess.

[photolytic]

As an experienced wet collodion photographer, I suggest the comparison would not be as easy as it appears. You’ve got a lot of extrapolation to do.

Fast wet plates have speeds up to ISO 1.5, or about 8 stops faster than B-Dags.

Also collodions containing bromide salts have significant sensitivity to green.

I’d suggest using a B-Dag test strip with a series of exposures on one plate to zero in on the best exposure. To determine the starting point in “variable weather” I’d advise using an exposure meter.

For UK experience you might contact David Burder in London at burder3D@AOL.com

[Marizu]

Thank you. Your posts are always very informative.

[Author]

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