Film Washing Test

[Photo Engineer]

Guys;

Here is my paper wash test.

Normal process, Dev, Stop, Fix, wash.

Fix = KRLF (Kodak Rapid Liquid Fix), Paper dilution, recommended time.

Paper = Ilford MG IV FB

Conditions = Runnin water, single sheet, 5x7 tray with 4x5 sheet.

When fresh, all of these looked equally white. They are now 5 years old. The retained Silver test is on the left and the retained hypo test is on the right. The test on the right (retained hypo) has darkened with age being Silver Nitrate. It required 2 - 4 minutes for complete washing to yield no change in stain with keeping. I ran that test as well, shown in the second figure. It is the only sheet that has shown no appreciable stain growth in the intervening 5 years. I'll let you know more in 5 years.

Please note that the retained Silver is still slightly positive, and the retained hypo is positive at 2 and 4 minutes, but since it darkens with age it is hard to tell now. However the paper still looks good! So, you can be fooled.

I have the same test with RC paper. It tells a totally different story!

PE

[Ole]

We could ask the moderators to make this a sticky.

Done, without asking.

[MattKing]

Guys;

Here is my paper wash test.

Normal process, Dev, Stop, Fix, wash.

Fix = KRLF (Kodak Rapid Liquid Fix), Paper dilution, recommended time.

Paper = Ilford MG IV FB

Conditions = Runnin water, single sheet, 5x7 tray with 4x5 sheet.

When fresh, all of these looked equally white. They are now 5 years old. The retained Silver test is on the left and the retained hypo test is on the right. The test on the right (retained hypo) has darkened with age being Silver Nitrate. It required 2 - 4 minutes for complete washing to yield no change in stain with keeping. I ran that test as well, shown in the second figure. It is the only sheet that has shown no appreciable stain growth in the intervening 5 years. I'll let you know more in 5 years.

Please note that the retained Silver is still slightly positive, and the retained hypo is positive at 2 and 4 minutes, but since it darkens with age it is hard to tell now. However the paper still looks good! So, you can be fooled.

I have the same test with RC paper. It tells a totally different story!

PE

Pray tell, PE, what the story is with RC.

Thanks in advance!

[Greg Davis]

Thank you, Ole. I would hate to see people ask this question over and over when it has been answered very well here (if I do say so myself).

[Photo Engineer]

For RC in the same conditions, the wash times were considerably shorter and NONE of the samples have browned even though they failed both tests. This is what is confusing to me at this time. In addition, I ran the same tests with TF-4 and the shorter wash times were fully verified and it passed all tests. TF-4 processed prints wash incredibly fast!

So, IMHO, the tests can fool you with RC. I'm still debating this with myself.

PE

[MattKing]

Could it be that the test is more sensitive to unwanted residue in the emulsion than residue in the paper (substrate)?

[Photo Engineer]

Baryta paper holds hypo and Silver complexes very tightly but RC papers and emulsions do not hold onto the residual stuff. The tests were positive, but the paper has not browned in the 15" wash time. I am reserving judgment! So, there are many factors to consider. For example, it may take 10 years for the RC to brown!

The TF-4 tests are much more straightforward.

PE

[Removed Account2]

According to the data sheet that came with the Hypo Estimator:
Density of Stain vs. Estimated Grams of Thiosulfate Ion/sq. meter
1=0.01
2=0.02
3=0.05
4=0.12

Well this is a yardstick that don't measure up to the job!

I'll explain that in simple terms.

A 35mm film is about 0,06 m2
Fixer is about 20% solution
In the film remains about 12 ml fixer absorbed in the emulsion, that is about 15 gram of solutiion.

Weight of fixer 15g x 0.20 equal to 3 gram fixer in the film.

Filling the tank from emty dilutes everything 1:20 and after a very short time equilibrium between concentration in film and water is reached (this time gets slightly longer as the concentration sinks)

Concentration before washing 3gram / 0.06 m2 = 50 gram per m2

1. tank 50 g/m2 : 20 = 2.5 g/m2

2. tank 2,5 g/m2 : 20 = 0.125 g/m2

3. tank 0.125 g/m2 : 20 = 0.00625 g/m2

4. tank 0.00625 g/m2 :20 = 0.0003125 g/m2

5. tank 0.0003125 g/m2 :20 = 0.000015625 g/m2

6. tank 0.000015625 g/m2 :20 = 0.000000781 g/m2

7. tank 0.000000781 g/m2 :20 = 0.000000039 g/m2

8. tank 0.000000039 g/m2 :20 = 0.0000000002 g/m2

The "yardstick" is meaningless already, it goes straight from 4 to 1 between tank 2. and tank 3.
And any difference from then on in these measurements is just random variations, and a single drop of fixer residue on one finger during the test will ruin everything as far as the hypotester goes.

You can calculate the same with running water, only difference is that it uses more water, long enough - and it is good enough.

The variation between non-hardening and hardening fixer, is also a matter of time mainly. Hardening fixer will take more time to reach equilibrium. In Ilfords method this is simple : use minutes, as a time measure, instead of seconds.

3 tanks of water is enough, 4 is plenty!

10 changes of water, according to Kodak, is a way over the top.

More time in running water will simply mean you use more water, if that is OK, the end result will be fine.

Hypo test agent is a waste of time, it is in effect a GO - NO GO measure test that can be used just one time, to self-assure that you do things right.

Disclaimer : I'm talking FILM here, paper is a different matter, since the different bases behaves way different as far as absorption of fixer goes.

But having several trays for washing - shifting from one to another, clean one is always better in theory than running water, IMHO.

ep

[Removed Account2]

According to the data sheet that came with the Hypo Estimator:
Density of Stain vs. Estimated Grams of Thiosulfate Ion/sq. meter
1=0.01
2=0.02
3=0.05
4=0.12

Now its just as simple to calculate this for running water also, and it will give just as good results - given enough water and time. Proponent for this procedure is that it takes care of itself, once set up, and if one has control over the water temperature, in case variations gives rise to reticulation.


First always take into account that the first tank filling, until overflow is exactly the same as the first tank filling in the Ilford procedure! Therefor one does NOT start from max concentration in the film, but from 1/20th of that. After that its just a case of simple dilution.

Like before there's 50 gram thiosulphate per square meter film to start with.

During slightly less than the first minute concentration is reduced to 1/20

Start : 50 g/m2

1 minute : 50 g/m2 : 20 = 2.5 g/m2

5 minutes dilution : 4,75l water, dilution 1:7.5
concentration after 5 minutes : 2,5 g/m2 :7.5 = 0.333333 g/m2

10 minutes dilution : 8,5l water, dilution 1:9
concentration after 10 minutes : 0.3333333 g/m2 : 9 = 0.0370 g/m2

20 minutes dilution : 17,0l water, dilution 1:17
concentration after 20 minutes : 0.0370 g/m2 : 17 = 0.002178 g/m2

30 minutes dilution : 25,5l water, dilution 1:17
concentration after 30 minutes : 0.002178 g/m2 : 17 = 0.000128 g/m2

40 minutes dilution : 34,0l water, dilution 1:17
concentration after 40 minutes : 0.000128 g/m2 : 17 = 0.0000075 g/m2

I think its pointless to continue this, compared to the Ilford method, which is exponential, this method instead is a steady dilution, it takes longer, it uses a lot more water, but it's less work, once set up.

IMHO there's little point continuing after 30 minutes, the concentration is already archival levels, just as 4 changes of water according to the Ilford method is more than adequate.

If one uses hardening fixer, one needs more time, if thats the case 40 minutes might not be enough. But 6 changes of water, while one let the tank stand long enough to reach equilibrium between water in the tank and fixer remnants inside the film layers certainly are!

You choose your way of work, and can rest assured that both ways will work adequately, one you adjust to the chemicals you use, and makes sure your clean and don't contaminate with fixer left on the bench etc etc etc, remember we end up with virtually clean, nearly drinkable water inside that tank!

[ntenny]

Filling the tank from emty dilutes everything 1:20 and after a very short time equilibrium between concentration in film and water is reached (this time gets slightly longer as the concentration sinks)

What makes you think it's a very short time? I haven't investigated this myself, but I recall reading someone's results in which they concluded that stand time in the rinse water was a highly important variable in the amount of residual hypo, precisely because it takes some time for that equilibrium to be reached.

I'd like for you to be right, however, as it means my film is better rinsed than I thought. :-)

-NT