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Jobo & Pre Rinse?



 
 
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  #11  
Old August 16th 11, 12:36 AM posted to rec.photo.darkroom
Frank Pittel
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Posts: 92
Default Jobo & Pre Rinse?

I got a recipe for xtol and the only thing that was a challenge to get
was the "DTPA" and I'm convinced that EDTA would work just as well. I got
the DTPA from artcraft chemical and dimezone-s from the Photographers Formulary.


Richard Knoppow wrote:

: "Keith Tapscott."
: wrote in message
: ...
:
: Richard Knoppow;927979 Wrote:
:
:
: There ARE better developers than D-76 but its very
: reliable and works for nearly all films coming close to
: the
: results from the better developers, so I continue to use
: it.
:
: --
: Richard Knoppow
: Los Angeles
: WB6KBL
: ou mention that there are better
: developers (plural, not singular) than
: D-76, which one's are you referring to?
:
: Xtol is supposed to be more eco-friendly and is often
: cited as giving a
: slight improvement over D-76.
:
:
:
:
: --
: Keith Tapscott.

: Kodak indicates that Xtol will yeild slightly higher
: speed, slightly finer grain, and slightly greater acutance
: than D-76. The only problem with Xtol is that it got off to
: a bad start with the sudden death syndrome. I have not heard
: anything about this for some time so perhaps its been cured.
: Xtol is also a self-replenishing developer, that is, the
: same solution is used for replenishing so one does not have
: to stock two different solutions. Its probably the optimum
: developer for most B&W use. AFAIK no one else makes an
: identical developer although some may have names that
: suggest they are the same. The patents for Xtol are
: available and I suppose one could mix the stuff from scratch
: but I think some of the components might be a PITA to find.
: Having said that D-76 works for nearly everything and
: while not quite as good as Xtol its close. Its easy to mix
: from scratch if necessary and is absolutely reliable.


: --
: Richard Knoppow
: Los Angeles
: WB6KBL
:




--




-------------------
Keep working dumbo needs the money
  #12  
Old August 17th 11, 06:30 PM
Keith Tapscott. Keith Tapscott. is offline
Senior Member
 
First recorded activity by PhotoBanter: Feb 2005
Posts: 112
Default

Quote:
Originally Posted by Frank Pittel View Post
I got a recipe for xtol and the only thing that was a challenge to get
was the "DTPA" and I'm convinced that EDTA would work just as well. I got
the DTPA from artcraft chemical and dimezone-s from the Photographers Formulary.


-------------------
Keep working dumbo needs the money
I may try the formula for the Xtol patent, but I will use metol at 2 grams per litre in place of dimezone-s.
  #13  
Old August 18th 11, 12:32 AM posted to rec.photo.darkroom
Frank Pittel
external usenet poster
 
Posts: 92
Default Jobo & Pre Rinse?

Keith Tapscott. wrote:

: Frank Pittel;929863 Wrote:
: I got a recipe for xtol and the only thing that was a challenge to get
: was the "DTPA" and I'm convinced that EDTA would work just as well. I
: got
: the DTPA from artcraft chemical and dimezone-s from the Photographers
: Formulary.
:
:
: -------------------
: Keep working dumbo needs the money


: I may try the formula for the Xtol patent, but I will use metol at 2
: grams per litre in place of dimezone-s.

Is there a reason for using metol instead of dimezone-s? My understanding is
that dimezone-s is a form of phenidone. The next time I mix up xtol I'm going
to try using edta instead of the dtpa. The dtpa in the quantities I'm ever going
to use the stuff at is expensive. Of course I bought 100gm of the stuff and the recipe
I have uses 1gm per liter of stock and I've got a supply of the stuff that will
lat me for years at my current rate of use! :-)
--




-------------------
Keep working dumbo needs the money
  #14  
Old August 18th 11, 03:52 AM posted to rec.photo.darkroom
Frank Pittel
external usenet poster
 
Posts: 92
Default Jobo & Pre Rinse?

Frank Pittel wrote:
: Keith Tapscott. wrote:

: : Frank Pittel;929863 Wrote:
: : I got a recipe for xtol and the only thing that was a challenge to get
: : was the "DTPA" and I'm convinced that EDTA would work just as well. I
: : got
: : the DTPA from artcraft chemical and dimezone-s from the Photographers
: : Formulary.
: :
: :
: : -------------------
: : Keep working dumbo needs the money


: : I may try the formula for the Xtol patent, but I will use metol at 2
: : grams per litre in place of dimezone-s.

: Is there a reason for using metol instead of dimezone-s? My understanding is
: that dimezone-s is a form of phenidone. The next time I mix up xtol I'm going
: to try using edta instead of the dtpa. The dtpa in the quantities I'm ever going
: to use the stuff at is expensive. Of course I bought 100gm of the stuff and the recipe
: I have uses 1gm per liter of stock and I've got a supply of the stuff that will
: lat me for years at my current rate of use! :-)

Minor correction. I bought 250gm of DTPA instead of 100gm. :-)
--




-------------------
Keep working dumbo needs the money
  #15  
Old August 18th 11, 05:01 AM posted to rec.photo.darkroom
Thor Lancelot Simon
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Posts: 163
Default Jobo & Pre Rinse?

In article ,
Richard Knoppow wrote:

There are two reasons Jobo reccomends a pre-soak. One
is that it saturates the emulsion and contols the rate of
uptake of the developer. That insures it is taken up evenly
to eliminate blotching. The development is also slowed
somewhat because the "induction time", that is, the time
between immersing the film in the developer and the time the
image begins to appear, is lengthened. Because of the very
rapid agitation in the drum the development time is quite
short compared to other non-machine methods so that
increasing it a little also tends to insure uniformity. The
second reason is to temper the tank. This is more necessary
for color development done at elevated temperature so that
the temperature of the developer is not suddenly changed
when entering the tank.


I strongly recommend *against* use of a pre-soak when developing
color film in a Jobo. I think if you peruse the various web fora
you will find a number of former Kodak chemists making the same
recommendation-against.

Many modern Kodak materials (at least) are manufactured in such a
way that developer penetration into the emulsion is controlled by
an "overcoat" of non-sensitized material. Among other issues,
pre-soaking defeats this, so that you are not developing the film
as its designers intended and may not obtain the same curves they
publish, even with the same developer at the same concentration. A
nuisance with black and white materials, but a more serious issue
with color ones.

Kodak recommends either the use of temperature controlled hot air
blown into the tank instead of a presoak (I do not know what kind
of rotary-tube machine can do this) or a longer preheat with the
tank in the water bath but no liquid in the tank. I use the latter
method and have always had good results even with processes with very
short times for some steps such as C-41RA.

--
Thor Lancelot Simon
"All of my opinions are consistent, but I cannot present them all
at once." -Jean-Jacques Rousseau, On The Social Contract
  #16  
Old August 18th 11, 04:18 PM
Keith Tapscott. Keith Tapscott. is offline
Senior Member
 
First recorded activity by PhotoBanter: Feb 2005
Posts: 112
Default

Quote:
Originally Posted by Frank Pittel View Post
Is there a reason for using metol instead of dimezone-s?

My understanding is
that dimezone-s is a form of phenidone. The next time I mix up xtol I'm going
to try using edta instead of the dtpa.
---------------------
Keep working dumbo needs the money
I prefer the standard MQ Borax (D-76/ID-11) to the PQ Borax (ID-68) developer and I suspect that I will also like the Metol (Elon) variant of Xtol as well.
I also find Metol much easier to weigh than Phenidone.

You are correct that Dimezone-S is a Phenidone derivative.

EDTA (fe) might work with the developer, but why not just stick with the DTPA now that you have already bought some?

For Xtol-M (Metol), I would start with the times given for D-76 and ID-11.
  #17  
Old August 18th 11, 06:37 PM
Keith Tapscott. Keith Tapscott. is offline
Senior Member
 
First recorded activity by PhotoBanter: Feb 2005
Posts: 112
Default

EDTA (fe) should have been written as EDTA (NA-FE), oops.
  #18  
Old August 19th 11, 05:49 AM posted to rec.photo.darkroom
Frank Pittel
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Posts: 92
Default Jobo & Pre Rinse?

Keith Tapscott. wrote:

: EDTA (fe) should have been written as EDTA (NA-FE), oops.

I knew what you meant. :-)

--




-------------------
Keep working dumbo needs the money
 




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