Pyrocat hd Tri-x black spots

[Hans Mulders]

today I developed one 135 mm roll Tri-x in pyrocat HD.
1+1+100 20 Celsius 10 minutes exposed as 200 asa.
Jobo tank, agitation every 30 sec. 408 ml in total of chemistry used.
Fresh Alcalic fixer used.
The negatives look very nice but on several images I notice some small black spots on the film.
It is not an over aged film. Exp date November 2017.

Any thoughts on this?

 

[Andrew O'Neill]

There are actual black spots on the negative? It's interesting that the spots only appear on some of the frames. How's your water?

 

[Hans Mulders]

I use water straight from the tap.
So no Demi water.
Next time I will use Demi water. Maybe this is the cause?

 

[Andrew O'Neill]

It could be, Hans, considering you used fresh fix, so bad fix is ruled out. How well are you rinsing the film before you fix it? I'm assuming you're not using an acid stop bath since you are using an alkaline based fixer. I use also use a mild citric acid stop bath even with an alkaline fix.

 

[Hans Mulders]

The stop bath is fresh and citric acid based.

 

[Andrew O'Neill]

Interesting. Hopefully it's a water thing then. Good luck!

 

[Andrew O'Neill]

Hey, do you look at the negatives right after you fix them? I'm wondering if the spots are happening during processing, or after... like during the wash, or wetting agent bath?

 

[Hans Mulders]

I washed the film with tap water 20 Celsius.
Last bath was with a little wetting agent.

I noticed the spots after the film dried when I placed it on the light table and checked the images one by one with a loupe before storing the film.

Tomorrow I will get distilled water for the developer.
Should I use distilled water for the stop bath and fixer also?
Never did this before.
However I'm a beginner with pyrocat developer.
Did some films already but no black spots, very lickely I had luck with these and is pyrocat developer more sensitive to minerals in the tap water.

Thanks Andrew to help me out with this

 

[Gerald C Koch]

Assuming that there is no visible material ON the film. This sounds like the developer was not completely mixed. Particles of either developing agent or alkali will cause this type of spotting. Development is enhanced where they stick. Has nothing to do with the water, stop or fix. Filter the stock solution and you should be fine. Next time you mix developer check to make sure everything dissolves.

 

[Andrew O'Neill]

Good point, Gerald.

 

[Hans Mulders]

Hi Gerald,
Thank you also for your input.

Just had a quick look at the developer.
I have two bottles one with solution a and one with solution b.
Both are liquids and I don't see any particles swimming around or on the bottom.
I used two separate injection needle containers to measure the amount. Both were cleaned before using but in tap water.
The water is heated up in an electrical boiler.

Do I understand your advise correctly, that after deluting the chemistry, first filter it and after that putting it in the developer tank?

 

[Gerald C Koch]

No, you may need to filter the stock solution. If you see no particles in the stock now may mean that in the interim any undissolved material finally did resolve.

http://www.pyrocat-hd.com/html/mixing.html

Observed the caveat for stock solution B. This has been a problem for several posters on APUG. The amount of potassium carbonate is very near the solubility limit at room temperature. Any particle sticking to the emulsion would cause what you see. It would be far better to halve the concentration in the stock solution and then just use twice as much. In other words 1 part A + 2 parts B + 100 parts water.

 

[Andrew O'Neill]

I would filter both stock solutions. Run them through there own coffee filter. Rinse the storage containers out, then replace with the filtered solutions. I've been using Pyrocat-HD for many years and never had to filter it.

 

[Hans Mulders]

Oke thank you both for your advice.
I will definitely gone do all of it. Filtering the stock solutions and use distilled water next time.

Thanks again

 

[john_s]

Can you inspect the negatives at a higher magnification to determine if the spot is a particle embedded in the emulsion (which is a bit soft and slightly prone to things sticking on it*) or on the other hand, a tiny patch that is overdeveloped (in which case Gerald Koch's suggestion of an undissolved particle of developing agent might be the cause.)

I don't agitate very frequently in developer but I got into the habit of agitating a fair bit in rinse then fix because I imagined that a particle in the solution would be less likely to adhere if not given a chance to remain on the surface while the emulsion was becoming firmer. I have no idea if that is right or not, but I use only tap water and haven't had a spot for decades.

* and yes, I know that modern emulsions are harder than the ones on which I learned in the 1960s.