Add Kodak Brown to KRST?

"Dan Quinn" wrote in message
om...
"Mike" wrote


I've googled this group and found numerous posts saying
that KRST at 1:20
doesn't provide adequate archival protection because it
won't tone the
highlights.


I think the silver in the highlight areas accepts
selenium as readily
as the silver in the shadow areas. If they are truly less
archivaly
protected then some other mechanism must be at work.
I think it may be a purely precieved lack of tone rather
than an
actual non-reaction twixt the selenium and highlight
silver.
In other words, I'm not a subscriber to the "split tone"
school
from the chemistry's view point.

Dan

The difference has to do with the size of the grains.
Finer grains have a larger surface to volume ratio than
larger grains so there is more surface to work on. This
seems to be at least part of the explanation. For some
reason polysulfide toners, where the polysulfides are of
higher orders, do not have this effect. Highly concentrated
stocks have lots of high order polysulfides.
Sulfiding toners of other kinds can produce split toning.
For instance the old Hypo-Alum toner split tones. Indirect
toner split tones but that is due to the effect of the
bleach, not the toner. Both KBT and T-8 are concentrated
enough to tone evenly when used for partial toning. Agfa
Viradon is currently a simple polysulfide toner like KBT and
has the same properties. I am not sure the simple addtion of
sodium or potassium sulfide to KRST would cure its problems,
maybe so, but I am not a good enough chemist to know. I am
sure Dr. Nishimura, and his associates at IPI, must have
thought of this.
I will also point out, that from personal communication
with Dr. Nishimura, that simple sulfiding is NOT as
effective as gold toning with Kodak GP-2. GP-2 remains the
standard of protection for microfilm. Diluted KRST was not
better, just a lot cheaper. (I've resisted calling GP-2 the
gold standard of protection, but I DID think of it).


--
---
Richard Knoppow
Los Angeles, CA, USA

"Francis A. Miniter" wrote

Hi Richard,

I just re-read the article: Nishimura et al "Stabiality of
Black-and-White Photographic Images, with Special Reference to
Microfilm", Abbey Newsletter July 1988 vol 12 No. 5


The following are extracts I believe important. More of that article
can be seen from Mr. Miniter's post. The entire article can be found
via Google.


"In any case, the surprising ineffectiveness of
Kodak Rapid Selenium Toner, together with many other signs of the
potency of sulfiding agents,..."

"Once we had determined that the
sulfiding ingredients were in fact responsible for most of the
protection imparted by dilute selenium and gold toners, we began to
explore ... at least one simple, extremely effective
approach has been identified: the use of polysulfides ... even when
used in quite dilute solution (1 part toner to 200 parts water)."

"It is characteristic of the sulfiding approach that only a small amount
of the sulfiding agent is needed. For example, sodium sulfide solutions
of 0.1 grams per liter (about 1/100th of a percent) are completely
effective."


" ... completely effective." There it is, the 1:9,999 dilution I've
mentioned. Contrary to Mr.Knoppow's assertion, Mr. Nishimura states
that
sodium sulfide does react with silver.


"However, for reasons of diminished odor, toxicity of the bulk
substance, and shelf life of the solution, the polysulfides are
preferable in practice to straight sodium sulfide. ... The method
of treatment is simple ..."

Mr. Nishimura is likely speaking of 5 to 55 gallon drums. I've
worked with sodium sulfide and never noticed any oder. I've used it
in the sulfer for silver test to confirm complete fixing.
Dan

(Dan Quinn) wrote

"Francis A. Miniter" wrote

Hi Richard,

I just re-read the article: Nishimura et al "Stabiality of
Black-and-White Photographic Images, with Special Reference to
Microfilm", Abbey Newsletter July 1988 vol 12 No. 5


The following are extracts I believe important. More of that article
can be seen from Mr. Miniter's post. The entire article can be found
via Google.


"In any case, the surprising ineffectiveness of
Kodak Rapid Selenium Toner, together with many other signs of the
potency of sulfiding agents,..."

"Once we had determined that the
sulfiding ingredients were in fact responsible for most of the
protection imparted by dilute selenium and gold toners, we began to
explore ... at least one simple, extremely effective
approach has been identified: the use of polysulfides ... even when
used in quite dilute solution (1 part toner to 200 parts water)."

"It is characteristic of the sulfiding approach that only a small amount
of the sulfiding agent is needed. For example, sodium sulfide solutions
of 0.1 grams per liter (about 1/100th of a percent) are completely
effective."


" ... completely effective." There it is, the 1:9,999 dilution I've
mentioned. Contrary to Mr.Knoppow's assertion, Mr. Nishimura states
that sodium sulfide does react with silver.


"However, for reasons of diminished odor, toxicity of the bulk
substance, and shelf life of the solution, the polysulfides are
preferable in practice to straight sodium sulfide. ... The method
of treatment is simple ..."

Mr. Nishimura is likely speaking of 5 to 55 gallon drums. I've
worked with sodium sulfide and never noticed any oder. I've used it
in the sulfer for silver test to confirm complete fixing. Dan

Pardon me, sulfur is correct sulfer is not. //