On Tue, 24 Feb 2004 18:57:22 GMT, Gregory W Blank
wrote:

In article ,
Mike Wilde wrote:

Most temperatures for b&W hang around 68 degrees, but, as the real
world knows, frequently the developer isn't that temp.

Why & why not?
In my darkroom in the winter the basement goes down to 62 overnight,
before the furnace kicks back up in the morning. I also do not have a
hot air duct directly from the furnace to try to keep dust
infiltration down. It takes until noon for the stock solutions to get
up to 68, if I do not have the exhaust fan running to pull warmer air
in from the rest of the house. .

In the summer , when the air conditioning is on it is no problem to be
as cold as the wintertime in the basement if one of my little ones
leaves the door at the top of the basement stairs open all day while I
am away at work.

68 has evolved into the reference standard for working at for a small
tank for times detwen 5 and 10 minutes as manufacturers plan thier
commercial formulations.

When solutions get warmer it can be a real quick dunk in the developer
soup. To get repeatable results when pouring into and out of a
daylight tank as well as knock all air bubbles off and agitate once or
twice when the total developing time is something like 3:30 is
difficult.

At the other end, trying to stay excited to agitate regularly when the
time slides out past 12 minutes whe the developer is cold is a bit of
a dull chore - hence the drive towards 68 degrees.

Withe a dial calculator it is easy to see what the recommended time
maps to for temperatures away from the reference time at 68.