Text based site map
Site © Copyright Barry Thornton 1999 - 2003
|
Brilliance in black & white
for you
The single bath option with DiXactol™ is
much less sensitive to factors causing development unevenness.
It does have other advantages too. It gives slightly greater
tanning, staining, and sharpness than two bath, and is usually
more economical. Compensation though is less - there is less
tolerance of under/over exposure than with the two bath. It
is still very high, and may well be more than enough for photographers
working with one film type which they know well, and with which
they have used good exposure technique.
For those who want to use the single bath option, yet still
want the compensation given by two bath and even greater edge
sharpness effects, there is a useful method - partial 'stand'
development. With this, after an initial 60 seconds continuous
agitation and tapping to release air bells, the tank is allowed
to stand still for two minute intervals between agitation. The
development time usually benefits by an approximate 10% extension
with this technique, but this is not critical. Some people may
be able to extend the 'stand' time to even longer intervals,
but there is an increasing risk of greater density on one side
of the film's width from the other, so experiment with care.
We now recommend single bath partial stand development as
standard.
If you normally use VC printing papers, try printing DiXactol™
negatives on graded paper as a comparison. You may well find
you like the bright tones on graded paper.
Times for single bath development are remarkably consistent
between 7 and 8 minutes for graded paper from film type to film
type: 9 to 10 minutes for VC paper. (Fine tune to suit your
enlarging equipment and preferences. Do not hesitate to vary
times - up if you are having to print on hard paper, down if
forced to print on soft). A few films differ. The main one is
Ilford Delta 400 which may well need 1½ minutes longer
to gain full printing contrast. It will still be printable even
if developed between 7 and 8 minutes, but will need a higher
grade of paper. Kodak IR film will need up to 11 minutes, and
there will be a high base fog, but this can be printed through
without problem. DiXactol™ is not suitable for ultra
high speed films such as Delta /T-Max 3200 where base fog is
too high and full speed is not realised.
Rotary or orbital development with continuous agitation is not
recommended. The developer's adjacency effects and compensation
characteristics are impeded. The relatively small amounts of
developer used in many of these devices also leads to premature
oxidisation and exhaustion of the solution. If a rotary/orbital
device is used, it is important that not less than 600ml of
working single bath solution is used as a minimum. Two 35mm
or 120 films, or two 5x4 sheets can be processed in each 600ml.
Continue ...
|
Back
|
|