[Leica] ASA, exposing, developing, T400CN

[Jim Brick <jim_brick@agilent.com>]

The number you set the ASA (ISO) dial, on your meter, for a particular
film, to is totally dependent upon what kind of a meter you are using and
how you take your readings.

On an M6, one person can set their meter to 200 and another person set
their meter to 800. Both take photographs all day, of the same stuff,
process their film together, and end up with the exact same density and
contrast negatives.

The difference is "where" you point your meter when you take a reading. If
you give precedence to the shadows, you will end up using a higher ASA to
get good printable negatives. Perhaps 800 for Tri-X. If you favor the
highlights (like with transparency film) you will end up using a lower ASA
(probably 200 for Tri-X) to get the same good printable negatives.
Remember, your meter sees everything as if it were neutral (approximately
18% gray).

Therefore, no one can answer the question "what ASA should I use with Tri-X
(or whatever film)."

Because it depends entirely upon how "you" use your meter when making
exposures. And of course, how you personally process your film. Constant
agitation in a JOBO. Once per minute in a tank? Once per two minutes in a
tank? Rodinal? D-76? HC-110?

Everyone has to work out the process, from front to back, to their own
liking. Especially using a reflected meter. This is why you hear some folks
say "I just love TMax 400 in Xtol" and someone else say "I cannot get
printable negatives from TMax 400 in anything!"

So giving advice on "which film at which ASA" and "which developer for how
long" is somewhat meaningless. You can think of it as a "starting" point,
to be refined over time.

However...

I've been using a lot of 35mm Kodak T400CN lately. But for you MF folks, it
now comes in 220 Pro Packs. I shot some 220 over the weekend and processed
it last night. I really like this stuff (35mm & 220.) Wide ASA latitude
(meaning it is difficult to make a mistake) and wide latitude in
processing. Very pushable. The negatives are always easily printable, very
fine grain, and sharp. It seems to be very difficult to block-up the
highlights into oblivion. Likewise, there always seems to be some shadow
density, regardless of the scene dynamic range and brightness. I'm getting
addicted to this stuff.

FWIW,

Jim