color print intensification
Christopher Bush
--
Christopher Bush
http://www.christopherbush.com
C. Grant DeWolf
few years ago.
It involves developing the print in B&W chemistry first, fixing,
washing,
then bleaching in a rehalogenating bleach.
After this, you can develop the prints in RA-4 in daylight.
Maybe Mr. Knoppow will have more detailed directions.
Colin
Ron Speirs
done it several times, and it does indeed create more contrast and
color saturation.
But there is one big problem to trying it now: The articles were
written when EP-2 was the current color print process. EP-2 is now
obsolete, along with the papers for that process. EP-2 used bromide
in the developer, and was "compatible" with B&W developers containing
bromide. RA-4 developer does not contain bromide, RA-4 paper does not
contain bromide, and bromide is considered a "contaminant" in the
process. RA-4 uses chloride instead.
It is possible that RA-4 paper will respond properly to this treatment,
but keep in mind the chemistry differences. The Anderson process used
Dektol as the first B&W developer; it may be necessary to concoct a
B&W developer which contains chloride instead of bromide. Some
experimentation would be in order.
Ron Speirs
C. Grant DeWolf <c...@glinx.com> wrote:
: There was an article in Creative Camera and Darkroom Techniques a
: few years ago.
: It involves developing the print in B&W chemistry first, fixing,
: washing,
: then bleaching in a rehalogenating bleach.
: After this, you can develop the prints in RA-4 in daylight.
Francis A. Miniter
The RA-4 materials works with the Anderson Process for increasing
contrast. I myself have applied it on several occasions with good
results. I use Dektol for the B&W developer.
Francis A. Miniter
Christopher Bush
"C. Grant DeWolf" <c...@glinx.com> wrote in message
news:3AA18E93...@glinx.com...
John
<cb...@dialupnet.com> wrote:
>Sounds good! What is a rehalogenating bleach and where can I get some?
>--
>Christopher Bush
>http://www.christopherbush.com
A rehalogenating bleach is one that recombines
bromide with the silver to form a halide. You can make
a mix up using potassium ferricyanide and bromide.
Unfortunately I don't have my formula at hand though I
think I used 100 g bromide and 100 g ferricyanide to
make a working stock of 2.5L.
Regards,
John S. Douglas Photographer
http://www.photographers-darkroom.com
===============================
Richard Knoppow
Unfortunately, I don't have the details of this process.
A rehalogenating bleach is one which converts the silver back into a
silver halide, most often silver bromide.
The bleach used for indirect Sepia toning is a rehalogenating
bleach. I dont know whether it would be suitable for this process or
not, but a suitable bleach would be similar.
A typical bleach is the one used for Ansco 221 Sepia Toner
Water (125F) 750.0 ml
Potassium ferricyanide 50.0 grams
Potassium Bromide 10.0 grams
Sodium Carbonate, monohydrated 20.0 grams
Water to make 1.0 liter
Bleaches like this are useful when its desired to redevelop a silver
image in some type of developer other than the one originally used. In
the case of toning, the image is redeveoped in a solution of Sodium
sulfide but any developer will do the job. Some intensification is
produced provided:
1, The film or paper is free of thiosulfate.
2, The developer does not have too much sulfite in it.
Thiosulfate combines with the bleach to form Farmer's reducer,
excess sulfite will dissolve some of the re-formed halide. Print
developers like Dektol have relatively little sulfite in them.
Film or prints given normal treatment with wash aid and normal
washing will be free enough of Thiosulfate not to cause bleaching.
I've seen a published process for rejuvenating faded color film and
prints somewhere, but can't remember the source. Annoying, usually I
remember this stuff.
---
Richard Knoppow
Los Angeles, Ca.
dick...@ix.netcom.com
Christopher Bush
So should I assume that once the print is bleached, it should not be exposed
to light until it reaches the bleach/fix?
--
Christopher Bush
http://www.christopherbush.com
"Richard Knoppow" <dick...@ix.netcom.com> wrote in message
news:3aa5b47d....@news.mindspring.com...
Colin DeWolfe
B&W Fix), all the rest can be done in roomlight.
It'll probably be the only time you will a get to see a colour
image form like you would a B&W image. :)
Colin
Richard Knoppow
>Thanks
>So should I assume that once the print is bleached, it should not be exposed
>to light until it reaches the bleach/fix?
>
>--
>Christopher Bush
>http://www.christopherbush.com
>
>
The rehalogenated image may _need_ to exposed to light to make it
developable. In fact, I would flash it with a fairly strong
incandescent light or expose it to skylight.
I think the only caveat here is that the processes before color
development must not destroy the color couplers or there will be no
color.
Flashing isn't needed when toning because sulfide or thiocarbamide
are fogging agents and develop all halide whether its been exposed to
light or not.
Color developer is a "normal" developer of a type whose reaction
products combine with the couplers to form the dye.
Christopher Bush
If I use a filter pack that would give correct color without the
intensification process, will that same pack still yield the correct color
with it???
--
Christopher Bush
http://www.christopherbush.com
"Richard Knoppow" <dick...@ix.netcom.com> wrote in message
news:3aa652ee...@news.mindspring.com...
Francis A. Miniter
The same filter pack is to be used. By the way, the Anderson
intensification process can be used repeatedly to increase contrast,
i.e., B&W developer, fixer, bleach, then B&W developer, etc., again
before going to the color developer. What is going on is that more and
more dye couplers are being activated with each go round.
Francis A. Miniter
Christopher Bush
developing times?
--
Christopher Bush
http://www.christopherbush.com
"Francis A. Miniter" <min...@attglobal.net> wrote in message
news:3AA6E4AB...@attglobal.net...
Sandor Mathe
> Hi Christopher,
> The same filter pack is to be used. By the way, the Anderson
> intensification process can be used repeatedly to increase contrast,
> i.e., B&W developer, fixer, bleach, then B&W developer, etc., again
> before going to the color developer. What is going on is that more and
> more dye couplers are being activated with each go round.
> Francis A. Miniter
Also you can mask out parts of the image (with rubber cement or equiv.)
before the colour development and then end up with a combined B&W
and colour image!
--
Sandor Mathe