Prewarming film emulsion
Dieter Zakas
the co-owners (brothers) described one of the kits, Tetenal, I think.
Reading from a product description, he said that particular kit required one
to "prewarm" the emulsion, presumably using warm water at 104 degress
Fahrenheit.
This got me to thinking: Could one use a similar approach with B&W? While
I'm not sure how it would affect development times, softening the emulsion
may enable the developer to do its work. (However, I should note that it's
been some time since I developed ANY film.)
Dieter Zakas
--
Good, better, best; never let it rest, until your good is better and your
better is best. (Billy Cox)
John
wrote:
> Recently, while inquiring about E-6 kits at my local camera store, one of
> the co-owners (brothers) described one of the kits, Tetenal, I think.
> Reading from a product description, he said that particular kit required
> one
> to "prewarm" the emulsion, presumably using warm water at 104 degress
> Fahrenheit.
> This got me to thinking: Could one use a similar approach with B&W? While
> I'm not sure how it would affect development times, softening the
> emulsion may enable the developer to do its work. (However, I should
> note that it's been some time since I developed ANY film.)
Most if not all manufacturers recommend that you do not "prewet" the films
prior to development as the water in the emulsion may impede develoment
progress and uneven development is theoretically possible. Note that I've
never heard of such a case. The other reason that don't recommend the
practice is that the rinse tends to rinse out the wetting agent that is
included in the film.
--
Regards,
John S. Douglas, Photographer & Webmaster
http://www.puresilver.org - http://www.legacy-photo.com
David Nebenzahl
So what difference would that make? Once the film is wet, why would you
need wetting agent?
--
... asked to comment on Michigan governor George Romney's remark that
the army had "brainwashed" him in Vietnam—-a remark which knocked Romney
out of the running for the Republican nomination—-McCarthy quipped,
"I think in that case a light rinse would have been sufficient."
(Eugene McCarthy, onetime candidate for POTUS)
Mike King
past (and may still) recommend a five minute prewash when processing black
and white. Since the temperature that black and white is normally processed
at is only a little above room temp the pre-wet is not so much for tempering
as it is for evenness of development. I currently use a Unicolor Film Drum
and motor base and use a five minute prewash. I have tried shorter presoaks
and with some combinations of film and developer got less than ideal
results. If you are going to use a presoak with black and white stick with
5 minutes. (At least until you can test and come up with a shorter standard
minimum time that works with all the combinations and permutations of film
type, developer type, temperature and agitation that you will use in your
own work!)
--
darkroommike
----------
"Dieter Zakas" <diete...@enter.net> wrote in message
news:BFAD2C01.12388%diete...@enter.net...
Claudio Bonavolta
> Recently, while inquiring about E-6 kits at my local camera store, one of
> the co-owners (brothers) described one of the kits, Tetenal, I think.
> Reading from a product description, he said that particular kit required one
> to "prewarm" the emulsion, presumably using warm water at 104 degress
> Fahrenheit.
>
> This got me to thinking: Could one use a similar approach with B&W? While
> I'm not sure how it would affect development times, softening the emulsion
> may enable the developer to do its work. (However, I should note that it's
> been some time since I developed ANY film.)
>
> Dieter Zakas
E-6 pre-warming is usually done *without* water, often during 5' to warm
up the tank/reel/film before 1st developer in which temperature is critical.
For B/W, both schools exist: pre-wetting or not.
Pre-wetting can be useful for short development times and reduces the
risk of developer streaks with larger formats.
You have to adapt your development time.
Personally I don't feel the need to pre-wet ...
Best regards,
Claudio Bonavolta
http://www.bonavolta.ch
Gregory Blank
> The other reason that don't recommend the
> practice is that the rinse tends to rinse out the wetting agent that is
> included in the film.
If that's the case how would the other three solutions fail to wash out
the wetting agent/ or do you mean there is wetting agent incorporated
to make the initial developer evenly coat the film? Btw I have never
added wetting agent to any film prior to the final rinse.
--
"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918
www.gregblankphoto(dot)com
Gregory Blank
Dieter Zakas <diete...@enter.net> wrote:
> Recently, while inquiring about E-6 kits at my local camera store, one of
> the co-owners (brothers) described one of the kits, Tetenal, I think.
> Reading from a product description, he said that particular kit required one
> to "prewarm" the emulsion, presumably using warm water at 104 degress
> Fahrenheit.
Well unless it states prewarming is done with water as a prewet, it is
an assumption. Not always good to assume!
> This got me to thinking: Could one use a similar approach with B&W? While
> I'm not sure how it would affect development times, softening the emulsion
> may enable the developer to do its work. (However, I should note that it's
> been some time since I developed ANY film.)
Here's my take: you'll get as many answers as practitioners, but
prewetting 5 minutes seems excessive, however 5 minutes prewarming is
probably correct, you do want to have the film-reel and tank at the
process temperature. By prewarming your insuring the times are accurate
for development, because times are established (hopefully) without lag
time factored as an unknown. Any time the film etc must come up to the
process temp -lag time exists.
I typically do prewash my large format film, ONE/TWO minutes
only....I feel it washes out the back anti reflection coating and does
warm the film up more quickly....I have never had problems but I
bidirectionally rotate or rock my drum drums during process.
I am quite sure there are many correct answers to your question as
the process can take a lot of variation and still yield VG results.
at @the-wire.dotcom Lloyd Erlick
<use...@puresilver.org> wrote:
>Most if not all manufacturers recommend that you do not "prewet" the films
>prior to development as the water in the emulsion may impede develoment
>progress and uneven development is theoretically possible. Note that I've
>never heard of such a case. The other reason that don't recommend the
>practice is that the rinse tends to rinse out the wetting agent that is
>included in the film.
November 26, 2005, from Lloyd Erlick,
And here I've been pre-soaking my film before
the developer for lo these many years ... oh,
well, wrong again.
regards,
--le
________________________________
Lloyd Erlick Portraits, Toronto.
voice: 416-686-0326
email: port...@heylloyd.com
net: www.heylloyd.com
________________________________
--
David Nebenzahl
> On Fri, 25 Nov 2005 23:23:47 -0600, John
> <use...@puresilver.org> wrote:
>
>> Most if not all manufacturers recommend that you do not "prewet"
>> the films prior to development as the water in the emulsion may
>> impede develoment progress and uneven development is theoretically
>> possible. Note that I've never heard of such a case. The other
>> reason that don't recommend the practice is that the rinse tends to
>> rinse out the wetting agent that is included in the film.
>
> And here I've been pre-soaking my film before the developer for lo
> these many years ... oh, well, wrong again.
I wouldn't say "wrong"; it's hard to see how a presoak could have any
ill effects, like uneven development. Seems to me it would have quite
the opposite effect, as the emulsion is thoroughly wet and the chemistry
can more easily diffuse through it. Wonder what Richard K. has to say
about this.
John
<greg@greg_____photo.com> wrote:
> In article <op.s0t09xxpuvfup0@jd>, John <use...@puresilver.org> wrote:
>
>> The other reason that don't recommend the
>> practice is that the rinse tends to rinse out the wetting agent that is
>> included in the film.
> If that's the case how would the other three solutions fail to wash out
> the wetting agent/ or do you mean there is wetting agent incorporated
> to make the initial developer evenly coat the film?
I believe that it is included in the emulsion during the coating.
Dieter Zakas
cla...@me.bonavolta.ch wrote on 11/26/05 5:30:
> Dieter Zakas a écrit :
>> Recently, while inquiring about E-6 kits at my local camera store, one of
>> the co-owners (brothers) described one of the kits, Tetenal, I think.
>> Reading from a product description, he said that particular kit required one
>> to "prewarm" the emulsion, presumably using warm water at 104 degress
>> Fahrenheit.
>>
>> This got me to thinking: Could one use a similar approach with B&W? While
>> I'm not sure how it would affect development times, softening the emulsion
>> may enable the developer to do its work. (However, I should note that it's
>> been some time since I developed ANY film.)
>>
>> Dieter Zakas
>
> E-6 pre-warming is usually done *without* water, often during 5' to warm
> up the tank/reel/film before 1st developer in which temperature is critical.
Thank you, Claudio, for setting me straight. I'd forgotten that the
prewarming was for the tank and reel, as I recall. Where I got the notion
that one would warm up the film emulsion is beyond me. Even so, it probably
couldn't hurt: after all, which would you rather do: spread butter taken
from the freezer on your toast, or use the butter that's been on the
breakfast table for ten minutes?
Dieter Zakas
Emulsion, NJ
John
<@the-wire.> wrote:
> And here I've been pre-soaking my film before
> the developer for lo these many years ... oh,
> well, wrong again.
Practice, practice, practice !
Like I said, I've never heard of it being a problem. I asked Kodak about
it and was told that it's just an unnecessary step for the most part. I'll
save 2~3 minutes where I can these days.
dan.c...@att.net
>
> So what difference would that make? Once the
> film is wet, why would you need wetting agent?
>
The instructions could read; " Pre-wet or not as
you damn well please." That being the case anyhow.
Perhaps it's a left-over selling point which used to
read, "no pre-wetting required".
There are some left overs and some that should
have been left over. Dan
David Nebenzahl
Well, it does no harm, so I do it. Worst effect is possibly a little
wasted time.
Steven Polgar
> dan.c...@att.net spake thus:
>
>> David Nebenzahl wrote:
>>
>>> So what difference would that make? Once the film is wet, why would
>>> you need wetting agent?
>>
>>
>> The instructions could read; " Pre-wet or not as
>> you damn well please." That being the case anyhow.
>> Perhaps it's a left-over selling point which used to
>> read, "no pre-wetting required".
>> There are some left overs and some that should
>> have been left over. Dan
>
>
> Well, it does no harm, so I do it. Worst effect is possibly a little
> wasted time.
>
>
Prewetting causes developer dilution, especially if you are processing with
critical quantity of developer. Kodak C-41 process does not suggest prewetting.
Frank Pittel
: In article <BFAD2C01.12388%diete...@enter.net>,
: Dieter Zakas <diete...@enter.net> wrote:
: > Recently, while inquiring about E-6 kits at my local camera store, one of
: > the co-owners (brothers) described one of the kits, Tetenal, I think.
: > Reading from a product description, he said that particular kit required one
: > to "prewarm" the emulsion, presumably using warm water at 104 degress
: > Fahrenheit.
: Well unless it states prewarming is done with water as a prewet, it is
: an assumption. Not always good to assume!
I've used the Tetenal kits with my Jobo and the prewarming was done with the film
in a "dry" tank. There's no prewash or prewet.
: > This got me to thinking: Could one use a similar approach with B&W? While
: > I'm not sure how it would affect development times, softening the emulsion
: > may enable the developer to do its work. (However, I should note that it's
: > been some time since I developed ANY film.)
: Here's my take: you'll get as many answers as practitioners, but
: prewetting 5 minutes seems excessive, however 5 minutes prewarming is
: probably correct, you do want to have the film-reel and tank at the
: process temperature. By prewarming your insuring the times are accurate
: for development, because times are established (hopefully) without lag
: time factored as an unknown. Any time the film etc must come up to the
: process temp -lag time exists.
: I typically do prewash my large format film, ONE/TWO minutes
: only....I feel it washes out the back anti reflection coating and does
: warm the film up more quickly....I have never had problems but I
: bidirectionally rotate or rock my drum drums during process.
: I am quite sure there are many correct answers to your question as
: the process can take a lot of variation and still yield VG results.
As you know I use a five minute prewash. I started doing so when I first got
my Jobo and that's what they recommended. Like you I've gotten good results with
a five minute prewash and I don't see any reason to change. :-) Of course all
I do is turn on the motor, pour in the water as I start a timer and then I can
walk away for the five minutes. :-) For what it's worth I would agree that after
two minutes the emulsion has more then likely absorbed as much water as it's going
to and extending the prewash to five minutes isn't providing any added benifit.
--
-------------------
Keep working millions on welfare depend on you
UC
temperature. E-6 films run at 100F.
F.C. Trevor Gale
black-and-white film, there is no reason to perform pre-warming provided
the film is around room temperature to start.
Some people *do*, however, advocate pre-*wetting* film especially to
avoid uneven development due to 'dry' patches as the developer is poured
into the tank - even more especially with shorter developing times. I
prefer not to mess around with too short a developing time in any case,
and I find no advantage at all in pre-wetting black-and-white film,
proper immediate agitation gets rid of any dry spots as the developer is
poured in.
In the case of C-41 chromogenic or colour negative film, development
temperature is 38 degrees Celcius. In this process I always perform 1
minute of pre-wetting at that temperature - for two reasons. Firstly, it
assures the film is up-to-temperature and wetted prior to development,
which takes 3mins 15seconds - 3mins 45seconds depending upon how many
rolls have been through. Secondly, it clears away the green
anti-halation layer which otherwise builds up rapidly in the developer
solution. On the rare occasion that I have processed E-6, I have done
the same.
My regards, F.C. Trevor Gale.