Archived posting to the Leica Users Group, 1998/09/06

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Subject: [Leica] TMZ revisited: the facts
From: Erwin Puts <>
Date: Sun, 6 Sep 1998 12:11:27 +0200

Here some densitometer values to prove the underexposure scenario.

	TMZ  as 1000	as 1600		as 3200

Zone 1		0,04	0,00		0,00
Zone 2		0,11	0,06		0,01
Zone 3		0,30	0,14		0,08
Zone 4		0,54	0,24		0,31
Zone 5		0,70	0,40		0,42
Zone 6		0,93	0,57		0,70
Zone 7		1,15	0,71		0,88
Zone 8		1,34	0,89		1,13
Zone 9		1,50	1,04		1,34
Zone 10		1,65	1,18		1,51

The film exposed at EI 3200 has been developed in Varispeed,designed to
exploit the inherent film densities. This can be seen in the higher values,
where the curve is steeper than in the EI1600 case (deleoped in XTOL).But
even the Varispeed cannot get shadow detail as can be seen in the lower
values of the shadow parts (zone 1 to 3). The EI1000 exposure gives a vey
nice curve and a printable range from zone 2 to zone 8. Below 0,10 and
above 1,30 there is no detail to be printed. What happens in the 3200 case:
we see the same values as in the 1000 case (0,08 to 1,34) but shifted two
stops. As theory has it. In many situations where you will use the EI3200,
the faces of persons are very well lit and the rest is dark. The very
overexposed faces are now high in the range and can be easily printed. No
shadows however, but quite often there is no shadow, so the absense of
shadow density will not be noticed.
Exactly the same analysis I did for Neopan 1600 and Delta400 and Tri-X all
at nominal speeds and 1 and 2 stops underexposed. Results identical, with
of course the usual variations in film character.
The thin negative of the ZMZ at EI1600 could be improved with some lobger

On temperature choice. I never noticed significant deviations when using 20
or 24 or 26 degrees C. Theorerically vigorous turbulence and higher
temperature accelarate chemical reactions, but in practice the differences
in grain structure are small.