Hold in HCA?

dancqu · May 13, 2007

I've been wondering when best to Hold when
doing a series of prints at any one session. Why
not hold in HCA? I can't think of any reason not
to. IIRC, Tim Rudman has recommended HCA
should follow the fixer. Any reason it would
not work as well for holding? Dan

Lee Shively · May 13, 2007

I've used a diluted bath of HCA in the holding tray. I've always followed with a running water rinse, selenium toner, another rinse and a fresh bath of HCA before the final wash.

Michel Hardy-Vallée · May 13, 2007

In the recent and substantial threads on fixing/HCA it was pointed out that HCA itself can be hard to wash out if you leave the print in it for too long. I personnally hold in plain water, it's cheaper and foolproof.

jstraw · May 13, 2007

mhv said:
In the recent and substantial threads on fixing/HCA it was pointed out that HCA itself can be hard to wash out if you leave the print in it for too long. I personnally hold in plain water, it's cheaper and foolproof.

I agree. Every minute in HCA, beyond the time required to clear residual typo is just creating an additional burdon on print washing.

Bob Carnie · May 13, 2007

I hold my prints in HCA before going to final wash, I prefer this than holding in a water holding bath as new prints are added in the solution is more concentrated with fix and would start bleaching finished prints.Therefore I go straight from fix to a short running wash with final prints then to the HCA. The wash is only a few minutes with finals , not test prints get to the HCA.
Having a continuous supply of running water at 68degrees over a 8hour printing session seems to be excessive and as well drains any hot water tank that I have ever had.
But this is a very good question, am interested to see how this goes.

dancqu said:
I've been wondering when best to Hold when
doing a series of prints at any one session. Why
not hold in HCA? I can't think of any reason not
to. IIRC, Tim Rudman has recommended HCA
should follow the fixer. Any reason it would
not work as well for holding? Dan

Michel Hardy-Vallée · May 13, 2007

jstraw said:
... beyond the time required to clear residual typo ...

Oups, I think you've just made an hypo!

dancqu · May 13, 2007

jstraw said:
I agree. Every minute in HCA, beyond the time
required to clear residual hypo is just creating
an additional burdon on print washing.

A hypo clearing agent is used to ease the washing out
of thiosulfate with or without attached silver. The active
components of perhaps all hypo clearing agents are sulfites,
ammonium or sodium. Sulfite converts to sulfate on exposure
to oxygen. Even IF sulfite/sulfate were slow to wash out,
where's the problem? The two are very soluble and
sulfite itself is a very weak fixer.

That amount of hypo left in the emulsion after completion
of washing is the "residual hypo". All else being equal that
residual level of hypo will be lower sooner using HCA. Dan

jstraw · May 13, 2007

dancqu said:
A hypo clearing agent is used to ease the washing out
of thiosulfate with or without attached silver. The active
components of perhaps all hypo clearing agents are sulfites,
ammonium or sodium. Sulfite converts to sulfate on exposure
to oxygen. Even IF sulfite/sulfate were slow to wash out,
where's the problem? The two are very soluble and
sulfite itself is a very weak fixer.

That amount of hypo left in the emulsion after completion
of washing is the "residual hypo". All else being equal that
residual level of hypo will be lower sooner using HCA. Dan

I'm concerned with residual chemistry that was absorbed by the paper base as well as the emulsion. I'm working towards a workflow built around the notion of the minimum required to thoroughly perform the task. This goes for all stages of film and paper processing.

jmcd · May 13, 2007

hold it

I don't think any print should just sit there in any chemical solution, nor too long in plain water, if there is residual hypo. After hypo, I rinse the print in a running water bath, then hold with other prints in water bath. Throughout the session I change the water in the holding bath, and shuffle the prints. At the end of the session, all prints are prepared for a final wash, which can include treating with HCA for the recommended amount of time.

AA's holding bath often was chilled to keep the emulsion intact.

A fellow I worked with had a holding tray by Zone VI that kept the water running through the system to keep the hypo diluted.

I stack two trays on top of each other. The top tray is riddled with 1/2 inch holes. This keeps the prints under a constant depth of water. Adding water to the top tray keeps has water flowing out through the holes, then into and out through the top of the bottom tray, so the residual hypo is continually diluted.

Interesting topic.

dancqu · May 15, 2007

jstraw said:
I'm concerned with residual chemistry that was
absorbed by the paper base as well as the emulsion.

I been wondering about that. Apparently the fiber and
in particular the baryta layer hang most tenaciously to the
thiosulfate and it's silver complexes. I use the ST-1 and
HT-2 tests both of which I've assumed are only to be
used on the emulsion.

I'm about to test some more fix-hca-wash scenarios and
will include the fiber side. Dan

jstraw · May 15, 2007

dancqu said:
I been wondering about that. Apparently the fiber and
in particular the baryta layer hang most tenaciously to the
thiosulfate and it's silver complexes. I use the ST-1 and
HT-2 tests both of which I've assumed are only to be
used on the emulsion.

I'm about to test some more fix-hca-wash scenarios and
will include the fiber side. Dan

I'll be curious to hear what you find out. I'm using HT-2 but haven't got my ST-1 yet.

Leon · May 15, 2007

jstraw said:
I'm concerned with residual chemistry that was absorbed by the paper base as well as the emulsion. I'm working towards a workflow built around the notion of the minimum required to thoroughly perform the task. This goes for all stages of film and paper processing.

I always hold in a small amount of Sodium Sulphite disolved in 1 litre of warm water straight from the fix. I then wash my prints ofr 10-15 mins. that is it. Water is a scarce and valuable resource so we must not overuse it. I've never had a FB print go bad.

Photo Engineer · May 15, 2007

Interestingly enough there is a problem with sulfite retention.

If you are using an ammonium thiosulfate bath, you will retain ammonium sulfite and this oxidizes to ammonium sulfate, a rather acidic compound. This can further decompose, but that is rather messy and not needed in the discussion here.

Basically, you end up with the sulfite salt of the dominant residual positive ion and you are lucky if it is sodium. It can be any of the positive salts including a small amount of silver sulfite. Any of these except for strong ions such as sodium will eventually result in excessive acidity in the paper support.

The suggestion of the experts is to NOT hold in HCA and to wash well after its use to remove all trace of sulfite ion and the hypo and silver salts that it is trying to 'clear'.

PE

jstraw · May 15, 2007

I'm with you PE...in fact...you got me to where I am:

fix(alkaline)>circulating water bath>HCA>circulating water bath>Selenium>circulating water bath for pre-wash rinse>wash

Michel Hardy-Vallée · May 15, 2007

jstraw said:
I'm with you PE...in fact...you got me to where I am:

fix(alkaline)>circulating water bath>HCA>circulating water bath>Selenium>circulating water bath for pre-wash rinse>wash

Don't forget that selenium toner contains sodium thiosulphate, so you need HCA after the toner as well if you want to shorten final wash time. Once, I made the mistake to use HCA only before the toner, and wash according to the times recommended on the HCA bottle. Good thing I made a residual hypo check!

dancqu · May 15, 2007

Photo Engineer said:
If you are using an ammonium thiosulfate bath,
you will retain ammonium sulfite and this oxidizes
to ammonium sulfate, a rather acidic compound. PE

Few are likely to Hold prints for further processing in
a bath of fixer. I have though given some thought to
combining the fix and wash. As some know I use fixer
very dilute. But so dilute as to wash with it? That I've
calculated would require way too much water. Dan

Photo Engineer · May 15, 2007

Dan, I think you misunderstood.

If you fix in an ammonium hypo fixer and then go into an HCA bath, normal ionic exchange will leave you with ammonium sulfite. If you then don't wash well enough, you end up with that being retained (among other things).

On standing, ammonium sulfite oxidizes to ammonium sulfate which is a rather acidic salt. This lowers the pH of the paper and emulsion depending on the extent to which it is retained in the coating and how much is oxidized.

The acidic content can also lead to decomposition of any retained thiosulfate and silver salts in ways not intended by the manufacturer.

So, the bottom line is that you must removed all HCA from your photographic materials that use an extended soak in HCA. That is why a long wash after HCA (to remove it) is good, and why an extended soak in HCA is not suggested.

PE

Anscojohn · May 15, 2007

Leon said:
I always hold in a small amount of Sodium Sulphite disolved in 1 litre of warm water straight from the fix. I then wash my prints ofr 10-15 mins. that is it. Water is a scarce and valuable resource so we must not overuse it. I've never had a FB print go bad.

****

Leon,
How long have you been printing?

Vaughn · May 16, 2007

mhv said:
Don't forget that selenium toner contains sodium thiosulphate, so you need HCA after the toner as well if you want to shorten final wash time.

I don't know if this is over-kill, but I mix my Kodak Rapid Selenium Toner 1:16with working strenght HCA...then follow with a rinse and then a HCA bath -- then a long wash.

The prints (on Portriga Rapid and Ilford Gallerie) still look good after 20 years, which is a relatively short period of time.

My silver print work flow is two 3-minute fixing baths, rinse, HCA (3 to 6 minutes) and hold in water, then a long wash. I wait until I have several images to tone (from several printing sessions) and do my toning in one session. I try to keep the developing, fixing and washing very consistant so that the toning times stay consistant...especially with the Portriga Rapid...to keep the print color consistant within my portfolio. It did not take much extra time to take the paper from a nice rich brown to a purple I did not want...and if I saw the color I wanted in the paper it was too late as it continued to change even after the rinse.

Vaughn

Ryuji · May 16, 2007

mhv said:
In the recent and substantial threads on fixing/HCA it was pointed out that HCA itself can be hard to wash out if you leave the print in it for too long. I personnally hold in plain water, it's cheaper and foolproof.

I don't know about the thread you are referring to, but washing time necessary for sulfite is very short; washing time required for removal of residual thiosulfate is far longer than that of sulfite. That is, sulfite retention is a non-issue.

Furthermore, any small amount of residual sulfite will get oxidized to an inert form. One reason sulfite is preferred as the washing aid, compared to sodium or ammonium chloride, is partly because sulfite is a lot more efficient washing aid, but also partly because residual sulfite is harmless to silver image while excess chloride can be harmful.

For the holding bath, if the prints are held before toning, there is no advantage to hold in HCA. But if the prints are held just before final wash, holding in HCA is an effective approach.

Ryuji · May 16, 2007

mhv said:
Don't forget that selenium toner contains sodium thiosulphate, so you need HCA after the toner as well if you want to shorten final wash time. Once, I made the mistake to use HCA only before the toner, and wash according to the times recommended on the HCA bottle. Good thing I made a residual hypo check!

Yes KRST contains thiosulfate, but selenium compounds and other toning agents (such as polysulfide) are just as bad to the image if not washed out of the emulsion and paper. HCA is effective in accelerating washing process of all these compounds and HCA is recommended after the toning process.

Michel Hardy-Vallée · May 16, 2007

Vaughn said:
I don't know if this is over-kill, but I mix my Kodak Rapid Selenium Toner 1:16with working strenght HCA...then follow with a rinse and then a HCA bath -- then a long wash.

Not necessarily a bad thing in itself, but HCA compounds degrade faster than those making the selenium toner, so after a while, the HCA in your toner will have no more effect than plain water, while the selenium is still kicking.

jstraw · May 16, 2007

Ryuji said:
...and HCA is recommended after the toning process.

I've been adjusting my workflow bit by bit and my most recent documentation to help me keep track...on my darkroom bulletin board reflects this. I got myself confused though and last night and distrusted my own document. I did the HCA before toning. Good to know I was on track when I wrote it and just confused last night. :rolleyes:

Hold in HCA?

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