Problem developing 120 film

LucianN · Aug 6, 2008

Hy
Maybe this was posted before but i am a new user...
So, these days i was developing a B/W film in a Pentacon Triplex tank with a corex band. The method was 30 seconds agitation (rotation of spool) in the first minute and after yhat every 10 seconds of the next developing minute. After fixation and final washing i noticed some dots on the negativ film (trasparent ones) thrue the emulsion where the image is. The dots are just on the side of the negativ... sometimes clearly visble sometimes absent... on the same roll of film. Could someone explain the nature of those dots and how to get read of them? Mention: those are not air bubbles, the film beeing pre-wetted befor loading into the spool (air bubbles create black spots on negativs as i know).
Tnx for any suggestions!
Regards LucianN

Ian Grant · Aug 6, 2008

I've seen clear dots very few times in about 38 years, but there are two possible causes.

1. The tank was contaminated, maybe hadn't been washed properly and fixer has crystallised getting into the developer.

2. Far more likely - small particles of iron in the water used, these react with the fixer causing it to bleach the image, you can filter the water & solutions to prevent this.

Welcome to APUG by the way

Ian

Trevor Crone · Aug 6, 2008

Another possible cause is dust settling on the emulsion at the taking stage. These of course will print as tiny black dots.

Out of interest are there a few or many clear dots and are they really tiny or large?

Again welcome to the wonderful world of analogue.

LucianN · Aug 6, 2008

The tank was brand new (unvraped form the original box) when those spots appeared. And also after each developing the film is removed from tank and washed (stop bath in wather) afther that put back in and fixed... again out with the film for final wash... meantime the tank lays is water.... So contamination wiht fixer i gues is out of discuttion. The other hand dots are aligned in what seams to form a line... No random spots are present on the negativ... Is it possible to be caused by the corex band??? The pattern is likely... Butt i never see before such a problem to any other photographers using the same tank and corex band.
Mention: The corex band was not so tightly riped around the spool... to let the chemycals flow easely betwen the corex band and the film... others did the same and with good results...
Thanks for welcome wishes and for the answere Ian!

LucianN · Aug 6, 2008

Trevor - the dots are tiny at beginning ... groving to a point and after that decreasing again. The dots are trasparecies in the negativs at the margin of the image. So dust is not the cause of that.
Thank you for welcoming me... really a wonderfull world

Ian Grant · Aug 6, 2008

If it's only one film perhaps it's a coating fault.

Ian

LucianN · Aug 6, 2008

no.... multiple films same problem

Ian Grant · Aug 6, 2008

What make of film ?

Ian

LucianN · Aug 6, 2008

The film is Fomapan 100 ISO, but also developed T-Max 35mm with smaller amount of dots... I dought T-max is low quality on emulsion:| Could it be a mechanical problem.... corex band scratching slowly the emulsion on the film while i am agitating the spoll... ??? Still never see this kind of troubles before.

Bob F. · Aug 6, 2008

Can you post a scan of the offending negatives?

Cheers, Bob.

LucianN · Aug 6, 2008

Sorry... my scanner is pretty old ColorPage HR7 (Genius)... I could try but only tomonrow or later tonight i will upload them. Don't expect any quality...But hope to make the dots visble. I'll try scann the film today.

Ian Grant · Aug 6, 2008

Lucian, you should try a different developing tank, maybe it is the Corex. That style of tank was dropped a great many years ago by most manufacturers.

Your only going to find the cure by trying different options.

Ian

LucianN · Aug 6, 2008

If a find one... i would... I'll try to order from internet if they'll send to me... In the stores are pretty absent these days... here...

Ian Grant · Aug 6, 2008

If I was back in the UK I'd send you a Paterson tank, as I have some spare. Where about are you ?

Perhaps someone else can help.

Ian

LucianN · Aug 6, 2008

Romania No e-bay... no on-line shoping Sad but true! Hope we will get over this and start be regarded as humans!

Ed Sukach · Aug 9, 2008

What was the composition/ strength of the short stop?

In the past, I have had "pinholes" in film, caused by "recommended" acetic acid dilutions.

Photo Engineer · Aug 9, 2008

Your post indicates clear spots. Air bubbles form clear spots on negatives, not black spots.

Could you clarify this?

PE

LucianN · Aug 10, 2008

@Ed - Stop bath = pure simple water.... no acid solution
@Photo E - The film was pre-wetted in another tank...

FotoGys · Aug 11, 2008

Could it be caused by the possibly formed carbon gas in the emulsion when switching from alkali developer to acid stop or fixer.
I never use a (acid) stopbath for this reason but plenish with a tank fully filled with water agitate 25 seconds and repeat this 3 times (total takes 1'30') before putting the fixer in the tank.

Regards,
Guus

LucianN · Aug 11, 2008

Guus Thanks... but I am using watter as a stopbath. After the 8 minutes in developer I remove the spool with film from tank and put it in a bucket filled with watter for about 1 minute ... agitating in the same time the spool with film. After that i place back the spool in the tank (cleaned tank - washed) and fill it with fixer...

Photo Engineer · Aug 11, 2008

LucianN said:
@Ed - Stop bath = pure simple water.... no acid solution
@Photo E - The film was pre-wetted in another tank...

In the OP, I believe you said you had black spots on the negatives. This is not indicative of air bubbles, but rather some contaminant in the developer itself, or something on the film from the water that causes black spots.

So, something is not clear to me.

PE

Trevor Crone · Aug 11, 2008

In his OP he said 'transparent spots' which is why I thought of dust settling on the film before/during exposure.

Photo Engineer · Aug 11, 2008

Sorry, but I misquoted. Here is what I am referring to "air bubbles create black spots on negativs as i know". Air bubbles cause the white spots, not black spots and that is the comment that caused confusion with me. The white spots ARE probably air bubbles. Air bubbles don't cause black spots as he stated, and he thereby seemed to eliminate them as the cause of the problem.

Sorry for adding to the confusion.

PE

panastasia · Aug 11, 2008

I too, think the clear spots are caused by air bubbles - I always tap the film developing vessel on the bench or counter to dislodge them, I thought everyone did this as common practice.

Paul

Thomas Bertilsson · Aug 12, 2008

I can also relate to this. If it's along the rebate (edge) of the film, air bubbles get caught by the film spool so that no developer gets to that area. So when you fix your film, it will clear in those areas.
You can help to remove these air bubbles by rapping the tank against a hard surface (preferably with a towel between to prevent damage on the tank or the surface) several times each time you agitate. Or, if you're using some other kind of tank (I'm not familiar with the Pentacon), agitate so that you dis-lodge those air bubbles.
I have had this problem on occasion.
- Thomas

Problem developing 120 film

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