Re: [Leica] Developing problem

["Don Dory" <dorysrus@mindspring.com>]

Sorry to hear about your problems.  I think you will soon be using a
densitomiter to sort out what is going on.  Once you have a film, developer,
dilution, agitation, temperature combination that you like I would suggest
you sacrifice a roll in the following manner.


You will be shooting a standard gray card at about four feet, possibly with
some good humored person holding it.  The light should not change and I
wouldn't use the extremes of your shutter range or aperture range to avoid
vignetting issues or slow shutter issues.

first two frames blank meaning lens cap on and 1/1000 sec.
second frame 3 stops underexposed from metering a gray card
third frame correct exposure
fourth frame 3 stops over
fifth frame five stops over

What does all this tell you.  Well, you are going to have to do some
graphing and you are going to have to borrow a densitomiter.  Any decent
mini-lab will have one and if they aren't busy should read the film for you.
Choose an appropriate scale with density on the y axis and exposure on the x
axis.

First, the second, third, and fourth frames should be in a straight line, if
not then your combination is not doing what you thought it should so stop
and rethink the situation.  Also, if the whole thing is on a straight line
at 45 degrees then you have issues as well.

Basically, you are measuring film base plus fog,  zone  2, 5, 8, and 10+.
So, if the graph shows a classic s curve with a straight middle you now have
something to compare a new film or film developer combination with.  From
your description of your current set of negs the density will be lower and
the curve will not be as steep and I would suspect that the Dmax is close to
being in a straight line with the other frames.  So, you can increase time,
or temperature, or dilution to adjust the curve.  If the 10+ zone is not at
least ten times denser than the fb+f then I would suspect the developer
strength and discard as you did.

The beauty of a densitomiter is that you can make adjustments easily based
on the density.  So, lets say that frame 2 and 4 are not close to six
stops(0.3 to 1.8 density units) apart.  How far apart are they?  Adjust time
20% for each stop.  Is the 10+ shot in the straight line or starting to
flatten out?  If it is in the straight portion then you need to increase
development, temperature, or dilution to increase the contrast of the
negatives to the point that the 10+ point is flattening out..

If you have questions just ask:

Don
dorysrus@mindspring.com

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