Developing film twice.
 

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé

Developing film twice.
 

once its fixed that it

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"Gregory L. Hansen" wrote in message
...

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé

Developing film twice.
 

In article ,
Bhup wrote:
once its fixed that it

I suspected that. Thanks.



--
All outgoing emails are scanned with Norton Antivirus 2004
"Gregory L. Hansen" wrote in message
...

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé




--
"We need to remember that when we are faced with an unstructured problem
it is we who create the model in the form of a quantitative metaphor;
there is no correct model waiting in the wings for us to call onstage." --
Thomas L. Saaty, "Mathematical Methods of Operations Research" (1988)

Developing film twice.
 

Well...you can learn to do it yourself. It's really easy. Or...call your
local community college, high school or college....see if there is a photo
student who would do it. Know though that things can go wrong.

--
Thanks,
Gene Palmiter
(visit my photo gallery at http://palmiter.dotphoto.com)
freebridge design group

"Gregory L. Hansen" wrote in message
...

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé

Developing film twice.
 

Gregory L. Hansen wrote:
The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


You don't need a dark room to develope film or slides. Just the
chemistry, the tanks, and a changing bag or a dark closet. A book on the
process helps a lot too. You will need some tools as well such as a
thermometer, measuring cups and special containers but they are minor in
cost.

Developing film twice.
 

In article , Gregory L. Hansen
writes

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


As others have told you, once it has gone through the fixer all the
undeveloped silver salts are removed, and that's it. However, if the
film was put through the developer twice without having been fixed in
between, then development would continue and you would get a grossly
over-developed film. Assuming it is negative film, the highlights would
be completely blocked up and the contrast would go through the roof; the
results would almost certainly be unusable. It is possible to gain some
extra film "speed" by using a shorter exposure and a longer development
time, but this would usually only be about 20-30%, and the film has of
course been underexposed to compensate (though you still get increased
contrast). It is however difficult to do this in a mechanised C-41
process line, as the timings are usually fixed. Also, they usually put
the film through all the baths (including fixer) with no chance to get
it out in mid-process.

David
--
David Littlewood

Developing film twice.
 

"David Littlewood" wrote in message
...
In article , Gregory L. Hansen
writes

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.


As others have told you, once it has gone through the fixer all the
undeveloped silver salts are removed, and that's it. However, if the
film was put through the developer twice without having been fixed in
between, then development would continue and you would get a grossly
over-developed film. Assuming it is negative film, the highlights would
be completely blocked up and the contrast would go through the roof; the
results would almost certainly be unusable. It is possible to gain some
extra film "speed" by using a shorter exposure and a longer development
time, but this would usually only be about 20-30%, and the film has of
course been underexposed to compensate (though you still get increased
contrast). It is however difficult to do this in a mechanised C-41
process line, as the timings are usually fixed. Also, they usually put
the film through all the baths (including fixer) with no chance to get
it out in mid-process.

David

I worked with a lab that could push process by simply shutting off the
machine while the film was in the soup, before the stop and fix stages.
Unfortunately, they could only do it with 24 exposure rolls, as a whole 36
exp. roll was never all in the soup at one time.

--
Regards,
Matt Clara
www.mattclara.com

Developing film twice.
 

In article , Matt Clara
writes

As others have told you, once it has gone through the fixer all the
undeveloped silver salts are removed, and that's it. However, if the
film was put through the developer twice without having been fixed in
between, then development would continue and you would get a grossly
over-developed film. Assuming it is negative film, the highlights would
be completely blocked up and the contrast would go through the roof; the
results would almost certainly be unusable. It is possible to gain some
extra film "speed" by using a shorter exposure and a longer development
time, but this would usually only be about 20-30%, and the film has of
course been underexposed to compensate (though you still get increased
contrast). It is however difficult to do this in a mechanised C-41
process line, as the timings are usually fixed. Also, they usually put
the film through all the baths (including fixer) with no chance to get
it out in mid-process.

David

I worked with a lab that could push process by simply shutting off the
machine while the film was in the soup, before the stop and fix stages.
Unfortunately, they could only do it with 24 exposure rolls, as a whole 36
exp. roll was never all in the soup at one time.

Wow, that sounds a but hit-and-miss!

David
--
David Littlewood

Developing film twice.
 

Gregory L. Hansen wrote:

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.



Yup. Once it's fixed there ain't gonna be any more development.

Fixing removes the undeveloped silver from the film emulsion. Once you
do that, there's nothing to develop.

For B&W negatives, if they're a little underexposed, you can selenium
"tone" the negatives to give them a little more oomph.

Normally selenium toner is diluted 20:1. If you're going to tone the
negative, mix it at 3:1

What would happen if you just made a special instruction on the
mini-lab's bag and told them to process it as a higher speed film?
Process ISO 100 film as if it were ISO 200.

Developing film twice.
 

"Gregory L. Hansen" wrote in message
...

The local one-hour photo labs have very little ability to do special
requests like pushing film. And surely for good reason. But what would
happen if they just ran it through the developer machine twice? As I
recall, at some point it goes through a fixer bath that, well, fixes it,
and maybe it can't be developer further at all after that. But my
knowledge of the chemistry is really pretty sketchy.

Nope. After going through the fixer, there are no light sensitive chemicals
left on the film.
Jim

--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé