Hypo Clearing Agent side-effects?

Hi,

I have been developing film the same way for years using Agfa APX (25, 100) and the Efke KB line of roll films (25, 50 and 100). All has been souped in Rodinal at 1+50 or 1+100 with very few exceptions.
A friend handed me a package of Hypo Clearing Agent. He told me it would reduce my water usage to a minimum, as it reduces wash time to minutes. This sounded pretty appealing to me, as my wash time normally is 20-30 minutes. Water is such a precious commodity.
Excited I developed a roll of APX 25, and decided to try the Hypo out. When I took the roll off the reel, for the first time ever I had a completely clear film base. This was surprising to me, as I have been used to my negatives being a certain way for so long.

As you can tell, I haven't ventured into too many experiments with film chemistry.
This came as a complete surprise to me and Iamb wondering if it's normal that Hypo makes the filmbase completely clear.
I don't want to develop any more film with Hypo until this is "cleared up"

Thanks kindly,


- Thomas

Saint Paul, MAN

I know this is going to sound crazy, but the manner in the way you state the question leads me to ask this one.. Did you use the HCA as a developer?

If so, this is the problem as it is to be used after fixer.

If not, clear film would lead me to wonder if the film was exposed.

If you want to cut down on the wash times, check out Ilford's recommendation on film washing at their site.

huggyviking said:

Hi,

A friend handed me a package of Hypo Clearing Agent. He told me it would reduce my water usage to a minimum, as it reduces wash time to minutes. This sounded pretty appealing to me, as my wash time normally is 20-30 minutes. Water is such a precious commodity.
Excited I developed a roll of APX 25, and decided to try the Hypo out. When I took the roll off the reel, for the first time ever I had a completely clear film base. This was surprising to me, as I have been used to my negatives being a certain way for so long.

- Thomas

Saint Paul, MAN

Click to expand...

Thomas, I think you misunderstood your friends use of Hypo Clearing Agent. It is not Hypo, as it is not a fixer. The purpose of HCA is to remove excess hypo to aid in reducing wash times. You would fix film/paper like you always do, then rinse, then place in HCA for x amount of time, then wash. Do a search on HCA or Hypo Clearing Agent, to find more info on times, etc.

Good luck.

Now all you need to do is wash out the HCA.

Hi all,

thank you for your answers. I have developed the film as I normally do.
1. Rodinal
2. Water rinse ~ 2min (instead of stop bath)
3. Fix ~ 2min 30sec
4. Water rinse ~ 30sec
5. Hypo Clearing Agent ~ 5min
6. Water rinse ~ 3 min
7. Photo Flo
8. Dry film over a humidifier

Everything as normal except for a shorter rinse and the added Hypo Clearing bath.

As 'Jdef' suggested, the clear film base is normal. Yes, other than that the negs look about normal. They will probably print differently, I suspect I will need to reduce contrast some - which is not at all something I want to deal with.

'Tom Hoskinson' - you suggested that all I need to do is to wash out the agent. Does that mean that HCA is a bad thing that will limit the archival qualities of the film, or does it simply mean that I have an easy job ahead of me washing that out instead of
washing all of the fixer out?

Apart from all this - would the sole benefit of HCA be to rid the fixer from the emulsion quicker than a water bath? Or are there other benefits as well? (I realize that some people perhaps like the totally clear film base, so for them that would be a benefit).

Thanks everyone,


- Thomas

Saint Paul, MN

Hi Ann,

thanks for your time. I was actually aware of Ilford's film washing recommendations, and I use the technique they describe, only for a lot longer than they recommend.

My theory is that water needs to be in contact with the emulsion for a certain period of time to penetrate it and wash it out, no matter how much you agitate.
I am probably wrong about this, but better safe than sorry - that's my motto.

Anyway, thank you for your help. I appreciate it very much.


- Thomas

Saint Paul, MN

ann said:

I know this is going to sound crazy, but the manner in the way you state the question leads me to ask this one.. Did you use the HCA as a developer?

If so, this is the problem as it is to be used after fixer.

If not, clear film would lead me to wonder if the film was exposed.

If you want to cut down on the wash times, check out Ilford's recommendation on film washing at their site.

Click to expand...

i mis-understood something along the way, i thought you meant the whole roll of film was clear. Isn't it interesting how easy it is to mis understand and then we wonder why communication is so difficult.

Thomas,

you have stated that in your process the wash time is 3 minutes. Regardless to what Ilford states I would increase the wash time to at least 10 minutes. Better safe than sorry some where down the line. Are you willing to bet your images that 3 minutes is long enough?

lee\c

I use hca for fibre prints rather than film. Wash temperature is an important consideration along with time too.

HCA (sodium sulfite + auxliary components) should make film/print more archival, since it helps on removing residual hypo.
But there are reasons to believe that trace ammounts of hypo acts as a preservative..

So, who really knows?

Jorge O

I generally don't use anything but water with film and just extend the wash out to about 30 minutes.

I just use sodium sulfite for fiber prints and on the very rare occasion that I have to use RC I just wash for about 5 minutes and air dry.

lee\c

Thomas, you wrote: "'Tom Hoskinson' - you suggested that all I need to do is to wash out the agent. Does that mean that HCA is a bad thing that will limit the archival qualities of the film, or does it simply mean that I have an easy job ahead of me washing that out instead of washing all of the fixer out?"

HCA is not a bad thing. As Jorge said, HCA is primarily sodium sulfite and water. Fixing and washing film and RC paper is different from fixing and washing fiber paper.

It is more difficult to get residual fixer out of fiber based paper than film or RC paper. And, in general, the longer the fiber based paper soaks in the fixer, the more fixer will be absorbed by the fiber base and the more washing it will require.

If you use non-hardening fixer, film is easy to wash since the thiosulfate (fixer) is primarily in and on the emulsion and on the back surface of the film base. The first water rinse removes virtually all of the fixer on the surface and about half of the fixer in the emulsion. Removal of the fixer (or fixer complexed with HCA) from the emulsion is primarily a chemical diffusion process. Each subsequent water soak and change removes about half of the remaining fixer (or fixer/HCA combination). You will fairly quickly reach a point of diminishing returns with the washing process - this is the basis of the Ilford minimum wash procedure.

No matter how much you wash, you can't get to a fixer residual of zero - and it isn't necessary. The safest thing to do is do a residual fixer check after washing. See The Darkroom Cookbook, pages 179 - 181. Kodak HT-1a is a good test and there are other good ones.

To remove the antihalation die, you could use Sandy Kings procedure of dissolving one tablespoon of sodium carbonate in a liter of water. Use this solution to pre-soak the film for 5 minutes, followed by a water rinse. Then develop the film. Any residual die will be removed by the fixer.

Another good way to remove anti halation dye is sulfite or HCA at wash time. Since I increased the sulfite content of my fixer, films comes out of it clean.

Jorge O