processing defect? need some help

[erikg]

Cropped scan from 35mm neg. Notice white ring on baby's nose. I've seen this defect on 3 or 4 frames on this roll. it is hard to see here but it looks like a ring of low or no density surrounding a black speck of some sort. edges are sharp and rather uneven, could it be some kind of contamination? Film is 35mm HP-5+, developer is pyro-cat 2:2:100. anybody else see this kind of thing?
Thanks!
erik

http://www.flickr.com/photos/73534568@N00/84660076/

 

[scootermm]

its the effects of an air bubble.
Ive had effects like that alot before when the roll film wasnt spooled properly on the metal reels.
hope that helps

 

[David A. Goldfarb]

Air bubble seems like a good guess. Were you using stand development? That's one hazard of low-agitation methods. Rap the tank firmly on the counter after agitating, and that should help.

 

[erikg]

Thanks guys. I wish you could see the film because I don't think these are air bubbles.
They are very small, and although this scan doesn't show it very well they have a pretty crisp edge. Most air bubbles I have seen, and I admit I've only ever had them on 120 film, are larger with a softer edge, and only occurred near the edge of the film. These are near the center. I didn't use stand development, just regular agitation in a small stainless tank, and I do rap it. I've never had an issue before. Here is my theory as to what this looks like: It seems like a particle of something, either from the developer or the water came into contact with the film and created a micro area of extreme development, with the white line around it being a kind of edge effect, like a mackie line? Could this be possible? I've only seen this with this developer, which is pyro-cat liquid from photographer's formulary.

 

[Ed Sukach]

Possibly a "pinhole".

Do you use acidic shortstop?

If so, I'd try reducing the strength - usually 1/4 to 1/2 of that commonly "recommended" will prevent pinholes... or use a straight water rinse instead.

 

[erikg]

I just use water as a rinse, no acid stop. Should have mentioned that. The emulsion is intact, no hole, which would be a clear area on the negative, not dark.

 

[Photo Engineer]

Pinholes from acid stop bath is a myth unless the film is so soft or the temperature is so high that other problems would be observed. Besides, if the stop caused a probelm, you would see 'blisters' and 'fish scale' rather than pin holes.

Pinholes from air being trapped on the surface of film before or during development are another matter. They leave a small, well defined 'dot'. However, if you notice the pinhole in this example, it has a dark center which is unusual for a pinhole.

This spot reminds me of a coating defect called a crater, or a handeling problem called 'pick off'. I have not often seen either. If you can view this in reflected or incident light at a high angle, see if there is a depression at the site of the spots. If so, then this defect is likely the cause of your problem. The crater often has a small dark spot in the center.

A crater is a true manufacturing defect, and pick off can come about by manufacturing or handling problems both.

It would be useful if you could post your observation about the depression on the emulsion side of the film.

PE

 

[erikg]

I don't have the film with me, but I will check it out this evening and post what I observe about the depression on the emulsion. Thanks for helping with the depression in my head!

erik

 

[winger]

I live just north of you (Franklin,MA) and have access to microscopes at work if you need a closer look.

 

[erikg]

Bethe, thanks for the offer. I'm not sure I'll need to go that far as I looked closely at these areas on the emulsion side and I do not see any depression in the emulsion at all, the area is as perfectly smooth as the rest of the film. I noticed that not all of these areas, (I have found 3 on this roll) are as circular as the one I scanned, they are slightly elongated ovals, with a irregular speck in the center. So far, I'm sticking to my original theory of a particle of something not in solution touching the emulsion, does that make any sense?

 

[srs5694]

So far, I'm sticking to my original theory of a particle of something not in solution touching the emulsion, does that make any sense?

I vaguely recall hearing about such effects somewhere or other, but I don't remember the details, so I can't be of much help in nailing this down. There can also be emulsion defects that look similar, but from what I recall, at least one class of these defects tends to have "tails" similar to a comet's tail. There's some discussion of this latter problem in a (there was a url link here which no longer exists) about Fomapan 100 film. I don't think it's the same problem, but you might want to read that thread just to have a comparison point.

 

[Ed Sukach]

Pinholes from acid stop bath is a myth unless the film is so soft or the temperature is so high that other problems would be observed. Besides, if the stop caused a probelm, you would see 'blisters' and 'fish scale' rather than pin holes.
Pinholes from air being trapped on the surface of film before or during development are another matter. They leave a small, well defined 'dot'. However, if you notice the pinhole in this example, it has a dark center which is unusual for a pinhole.

First, let me say that I have the utmost respect for your attention here.

From experience, I had experienced numerous small, well-defined areas of *no* density (a.k.a. "pinholes" - or is another term better?) when using "full-bore shortstop" - as I remember it was, specifically, Kodak Indicating Shortstop, diluted 16ml/ liter.

I had attempted to contact Kodak, numerous times, about "pinholes" - always with the same result: no reply.

I then went to both Ilford and Agfa .. and they replied that there was a possibility that the strength of the shortstop *could* cause that defect .. and both advised a weaker dilution, or the elimination of acidic shortstop altogether.

I followed their advice, using nothing more than a water rinse, and last month, on *one* frame of Agfa APX 400 I did notice *a* pinhole, in one frame, the first I'd seen in five or six YEARS of film processing.

I guess the "myth-ness" is dependent on the source of the opinion.

Far less clear in my memory is the source of the idea that "dissolved oxygen" - outgassing during processing (possibility due to the acidic content) resulted in pinholes. The advice there: Let water to be used in mixing developer to stand for a few hours - overnight - to allow oxygen to escape.
I remember something about that - but I cannot comment about its truth, or its source. Suffice it to say, I do NOT use shortstop, of any kind in FILM processing - for what I consider to be good reason.

 

[fhovie]

I had a pinhole problem with tech pan. I finally figured it out one day when I was spooling up a roll in the darkroom. Static electricity was the problem. I made 2 changes. I wind it slower in the camera. I work with it slower and I humidify the darkroom before I start. That make a big difference.

 

[Photo Engineer]

Ed;

My bottom line is "use what works best for you".

For further information, I leave you with this.

I have run lab experiments on hardener levels at values from 0 - 10x normal hardener of formalin, mucochloric acid and the new hardener that Kodak uses. I have run processing temps from 68 - 120 deg F. I never got any problem whatsoever at normal hardener levels, and when I went very low, I got large blisters, fish scale like defects "scales", or the emulsion just washed off the film. I don't remember ever seeing a pinhole.

I was told that the only case of 'pinholes' from acid stop baths came about in deep tank paper processors where the stop bath and deep tank combination allowed carbon dioxide to build up in solution in the paper emulsion due to hydrostatic pressure at the bottom of the 4 - 6 foot deep tanks. As the paper traversed up out of the stop, the pressure reduction reduced the solubility of the gas and it fizzed out. This was reported in Eaton's book on Photographic Chemistry, published in the 50s, but was solved rapidly due to complaints.

This is the only documented 'event' of this nature and was addressed by EK immediately when it was observed.

I do get pinholes in film if I fail to use a good prewet or if I don't rap the tank hard against my hand to dislodge the air bubbles entrained in water.

If you run tap water fast into a container, and observe the cloudiness, this is due to entrained air in the water (NOT DISSOLVED GUYS - TRAPPED AS SMALL BUBBLES). Sorry for shouting. These are what cause airbells or air bubbles or white spots. If you dip a piece of raw film into water, you will start to see these bubbles appear on the surface of the film. If you move the film, you will dislodge the bubbles from the surface and they will float away. Once fully wet, no further bubbles will adhere to the surface of the film.

Just a further explanation on what could be a complete day seminar on bubble formation on film surfaces, gas formation in films and their effects, and hardener and gelatin effects on interstitial gelatin defects.

PE

 

[erikg]

An update-- I just ran another roll of film, keeping everything the same except using distilled water for mixing the developer. I still found two of these little areas, and I mean little. Same kind of thing, an elongated black speck with a clear ring around it. I have not been using a pre-soak with these rolls. That is what I will try next.

eg