35mm edge fogging

[david_leffen]

<p>Please excuse me if this question has been dealt with elsewhere on the forum. I have searched and found no relevant threads.<br>

For some time I have been experiencing fogging at the edge of my 35mm negatives. This has occurred with three different cameras and three different film types. I bulk load my films using plastic film cartridges from Freestyle.<br>

Most of the edge fogging occurs near the beginning of the negative. In all cases the period of the fogging is 6-7mm. Sometimes fogging also occurs further on the negative with a period of 20-22mm.<br>

I have tried to include a scan of a negative which shows the fogging but not the details of the negative. Generally the fogging does not intrude beyond the edges.<br>

I decided to analyze my results today since this has been a persistent problem. I measured the diameter of the rolled film (24 exposures) on a reel and found it to be 2mm. Note that this results in a circumference of 6.28mm (between the 6 and 7mm I measured on the negatives).<br>

The fogging appears at the edge of the negative which would be the top of the photograph. Since the optics invert the image then fogging occurs at the bottom of the film plane. This is the screw-on cap side of the cassette.<br>

I am speculating that the problem could be light leakage at the screw-on cap where the film leaves the cassette (light trap). It is odd however that this problem should occur on most of the cassettes. I must have 30-40 cassettes so it is unlikely that it is the same cassette every time. This would occur at one point around the circumference and would probably diminish or disappear for film nearer the middle and end of the strip.<br>

If anyone has encountered this problem and/or has any ideas for the solution please respond. Could all of my cassettes be bad? They have not been heavily used. I am open to buying higher quality cassettes if you could recommend any particular brands.<br>

Thanks,<br>

Dave</p>

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[bob_sunley]

<p>If you are using the plastic film cassettes do they have the little pointer to cover the light trap felt?</p>

[david_leffen]

<p>Yes they do have the little pointer. I must admit that I haven't paid much attention to them but I do line the pointer up with the flat ridge on the body of the cassette. Tomorrow I will load a cassette (paying special attention to the tab), expose it and develop the film. I'll report my results. Thanks Bob, that sounds promising.</p>

 

[thirteenthumbs]

<p>Light leak-multiple cameras-multiple film cassettes=loading technique or bulk film loader or both.<br>

Are you loading the cassettes in day light, subdued lighting or total darkness? Bob covered the first, second how much you loosed the lock knob of the bulk film loader to allow switching between load and lock position can cause a light leak if it is loosed too much and or the film gate of the bulk loader might have a nick or gunk buildup on it.</p>

[leicaglow]

<p>To me, because of the sharper edges, it looks more like the film was touching on the reel when it was developed and fixed.</p>

[david_leffen]

<p>Charles, I agree that it could be cassette loading technique and I hope to pay particular attention the next time I load film. I have been loading in day light. To be specific, in a normally lighted room, not overly bright but also by no means dark. The loader is a 40 year old Lloyd. It was unused for 30 of those years and hasn't seen a lot of use. There is no lock knob. The film gate is secured in place by the crank.</p>

<p>I think that the fact that the fogging occurs on the first few exposures and is a specific distance between instances might absolve the loader. Note that the fogging is actually near the end of the loaded film.</p>

<p>Michael, we may be talking about different fogging. I agree that the very narrow black lines along both edges were caused by contact with the reel, but I can live with those. It is the more irregular fogging at 19A,21 and 23 that I am concerned about.</p>

<p>Thanks for the suggestions and please keep them coming.</p>

 

[thirteenthumbs]

<p>On a Weston bulk loader the knob that you loosen to open the loader for film insertion holds the outer drum section which when installed rotates slightly opening a film gate that allows the film to be pulled freely from the storage drum and locks the cassette door closed while loading a cassette then when rotated to the lock position closes the film gate and allows the cassette door to be opened in daylight. Leaving this knob too loose so that the drum lock works very easily can result in a light leak.<br>

If the cassette loading technique does not cure the problem then look closely at the loader as these are the first two things common to the problem with the developing tank and reels the third.</p>

 

[david_leffen]

<p>Charles, after looking at my bulk loader I realized what you were talking about when you mentioned the lock knob. There is such a knob however its function is to allow one to open and close the loader for film insertion. It needs to be tightened securely and I have always done so. It appears to have no function as far as loading cassettes in the Lloyd loader.</p>

<p>As I mentioned, I intend to run a test today. I have carefully loaded a cassette and am now waiting for daylight to expose the film.</p>

<p>Results to follow!</p>

 

[lex_jenkins]

<p>Develop a short test strip in the tank without loading the film onto the reel. If the marks still appear along the edges you'll know it's not due to contact with the reel guides interfering with chemistry flow.</p>

[david_leffen]

<p>Well, I've run the tests. I exposed the carefully loaded cassette in my camera and developed the film. I'm still getting fogging near the beginning about 6-7mm apart as before. However, there is one difference in that the fogging occurs on the side of the negative with the numbers as opposed to the example above where the fogging is on the opposite side of the negative. There is also an area about in the middle of the exposures where the fogging appears across the height (i.e. the 24mm dimension) of the negative.</p>

<p>Lex, I also tried your test of a short piece (about 10 inches) of unexposed negative directly out of the film loader. Other than at the very end where it had been exposed the negative was perfectly clear. That seems to imply that the fogging has not occurred in the loader.</p>

<p>I think I have two more tests worth trying. The first would be to wind a piece of unexposed negative on a reel and develop as normal. The second would be to buy a commercial roll of black and white film and see if I have fogging after exposing and developing.</p>

<p>It's getting harder to find b&w film where I live so I would have to order it online.</p>

<p>I am using a Hewes reel but I have other older and cheaper reels purchased 40 years ago. Maybe I should try those?</p>

<p><br />Any more ideas?</p>

 

[thirteenthumbs]

<p>Switch to or try metal reloadable film cassettes.<br>

<a href="http://www.adorama.com/BLCM10.html?searchinfo=reloadable+film+cassettes">http://www.adorama.com/BLCM10.html?searchinfo=reloadable+film+cassettes</a></p>

[david_leffen]

<p>I tried winding a piece of unexposed film on the Hewes reel and developing it. There was no evidence of fogging so the reel has now been absolved. There were tiny black lines on the very edge of the negative presumably where the film touched the reel during processing. This doesn't bother me.</p>

<p>I want to make a couple of corrections to earlier statements. The plastic cassettes were not from Freestyle, but from B&H Photo. Also, the piece of undeveloped film was 15 inches and not 10 inches.</p>

<p>I am going to order some metal cassettes from Freestyle and a couple of rolls of film. I'll report the results.</p>

 

[david_leffen]

<p>The Freestyle cassettes arrived and I wound on some film. I exposed the film and developed as before. There is no fogging. Hardly a definitive test but it seems that the plastic cassettes were the culprits. I'll try more film and see what happens.</p>