Jose A Martinez,

We haven't mentioned "reciprocity law failure" which means you may need to give even longer times if you are running into exposures longer than 10 seconds since you are using a pinhole...

An old chart says it:

If indicated time is ... give this much time

1 sec ... 2 sec
10 sec ... 50 sec
100 sec ... 1200 sec

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Curiously, it is about the same as placing exposure on Zone VIII ... I wonder ...

Is the whole purpose of moving exposure to Zone VIII supposed to correct for reciprocity law failure?