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Half moon shadow on negative


r.m.

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Hello all. I have recently begun developing my 35mm b&w film at home

and have encountered a problem whereby a half moon shadow appears on

the lower edge of some (not all, but usually the ones I'm most

interested in!!) of the negatives in my roll. I'm using a 2 reel

Patterson tank, ID11 developer, Ilford stop & rapid fix solutions. I

load the film in a darkroom, pour the developer through the opening,

invert continuously for 30 seconds & then for 10 seconds every minute

thereafter. I've attached a quick scan copy of some such negatives.

Has anyone seen this before? Any suggestions? Thanks much.<div>003wUu-9986584.thumb.jpg.c1eac606980a03326a54196880b750c5.jpg</div>

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It doesn't look like kinked film. Kinked film results in dark crescent moon shaped marks. These are areas of reduced density in half moon shapes. You'd also have to be doing something seriously wrong if you're having a problem with kinks on plastic reels.

 

The fact that the shadows appear in almost exactly the same spot on each frame indicates it's a problem during exposure. My guess is you're using flash with a large lens, maybe with a lens hood and the lens or lens hood is creating the shadow from the flash. Most likely the on camera flash.

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Tom and Lex are correct! The crescents are LIGHT in the neg, and hence will be dark shadows on a print, and processing kinks are small, dark little nearly half circles on the negs.Something is in the way of the flash, or is somehow casting a shadow on your scene. This is NOT a processing anomaly, and you didn't say if you were using a strobe on-camera.
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Thank you all for getting back to me so quickly. I am not using a strobe. I'm using the Elan's built in flash, and a Canon 70-200mm lens with lens hood. Relieved to hear it's not a processing problem, but any suggestions on how to avoid same in the future? Thank you!
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No problem, Reina, none of us was born knowing everything...tho' some would have you believe otherwise. ;>

 

One trick I frequently use to minimize the half-moon shadow and to improve flash quality is to use a white styrofoam picnic plate as a flash diffuser. I cut a hole in it large enough to accomodate the lens - off-center, since the largest area of the plate should be oriented up for the flash coverage.

 

Besides creating softer, more even illumination, the diffuser also helps spread light around to the bottom and minimize that semi-circular shadow.

 

Looks dumb; works great.

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Reina: One possibility is that the film was kinked at some point though kinks are supposed to be the opposite colour. If it were kinked in the camera thereby affecting the emulsion, it could, I suppose produce this effect. To prevent kinks in the tank, when using plastic tanks one should always nip off the corners of the ends of the film before loading it in the tank. This would be a very small cut on each corner but enough to prevent jamming and subsequent kinking. This of course is done in the dark.

Another possibility is that you have contaminated your roll of film by excessive handling while loading. The half moons look a bit like finger prints but it is hard to tell. To eradicate this event you must make sure to wash your hands well before loading the tank and avoid too much handling of the film particularly in areas of the image.

Also be very careful to fully clean your tanks and make sure they are fully dry before using them. Wet tanks kink film.

Try these suggestions and good luck.

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Steve, have another look. The half moon areas are contained entirely within the part exposed by the camera. It is in the exact same spot in each frame. The edge markings show consistent density throughout even near the areas where the defect appears. These types of charecteristics can only be attributed to in camera errors. The possibilities of what you are claiming is causing this to actually happen and in such a precise way are practically impossible.
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Tom: I disagree. I am sure that these marks are caused by either chemical contamination, ie fixer contaminated fingers handling the negatives during loading of the film tank or a faulty tank reel or tank loading procedure whereby portions of the film gets buckled and is improperly developed. It is not uncommon for plastic tank reels, particularly older ones, to get very slightly bent causing the inner tracks to become slightly misaligned. The result is that portions of the film get bent enough to prevent uniform development or even rub together during development. Please check out the Kodak publications that demonstrate problem negatives and their causes for very similar, even exact examples. Also check out "The Darkroom Book" for similar demonstated problem negatives and their causes.

"In camera" transport problems can cause the film to become warped enough to cause improper development as well.

Remember Tom, Reina has stated that these marks DO NOT appear on every frame.

I have never seen flash caused problems such as these that occur on shots taken outdoors as these seem to be.

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Steve, while you may be right (I am after all the novice & can't be sure), I'm leaning towards the idea that this was, in fact, caused by the flash/lens/hood combo. First, I avoid using a flash whenever possible, as I prefer natural light, making the vast majority of my photos non-flash. I've developed about 40 rolls of film now over a 4 mo. period using the same new patterson tank & this problem has occurred on only two of those rolls. In each instance, the half moon appears when I used a long lens with hood at a close range in low light conditions & fired the flash. In the example I provided, you are correct in that the shot was taken outdoors, but it was also evening. The half moons do not even remotely appear on adjacent frames in which a flash was not used. To be sure, I will shoot one roll of film using the 70-200 lens w/hood, close up in low light with a flash, and another roll in the same condition without a flash. I will develop the rolls together in the same tank. If it is the flash, then I believe the first roll should have half moons on every frame. I'll post the results as soon as I have them :)
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Reina: With your additional information you do now present a perplexing question. If the problem does occur EVERY time you use the flash and lens combo then I definately concur with the flash as being the culprit. I do note however that there is a definite inconsistancy in uniformity of development well above the half moon defect areas. I believe that these areas should have increased density if they are flash reflections caused by the bounce off the lens as the area below would have a reduced density in the shadow from the lens. Does anyone else notice this?
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the 'half moon' looks very narrow for a lens shade induced shadow. Also the shape seems to alter a little (which could be different zoom setting on the lens) Anyone think that? I imagine Reina is scanning these on a flatbed without a transparency adaptor since they look so terrible. Have you got a print you can scan to show us?
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If anybody is really bored and desperate for entertainment I can reproduce those half-moon shadows perfectly using my digital camera. It's a result of a long lens or lens and shade and flash at close range.

 

Before attributing the marks to anything else consider first how they occur in exactly the same position on every frame shown. The likelihood of this being caused by kinking or other factor during exposure or processing is extremely low. I've kinked film during loading and the resulting marks do not occur on every frame, let alone in the same position on every frame.

 

Other than this we can't really tell anything from the supplied scan. I tried experimenting with it in Corel Photo-Paint but there simply isn't enough data to invert and tweak it satisfactorily.

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Reina,

 

That's definately a show produced by the lens. The pop up flash isn't high enough to clear a lens as big as that. You can do the testing if you want but trust me, that's what your problem is. Although you can do a miriad of tests to determine if your hands are clean enough, the reels are dry enough, the earth is revolving around the sun at precisely the right angle, your water is at the exact pH to the 7th decimal place and other such nonesense until Steve is convinced of what is causing the problem.

 

Reina, at first you said that it was on the shots you wanted to keep were the ones that had the half moon shape. Then in a later post you said you like to shoot with in natural light. A little bit at odds but here's some advice. The negatives look very dense, as if the flash is just washing out everything. You probably have your camera in one of the program autoexposure modes and the flash is being fired to properly expose the subject as the main light source, pretty much killing any natural light. Try playing with the flash in only fill flash mode to get more natural light in the shot. For the shots that aren't at night at least :) Av or Tv mode on most cameras will properly expose the scene but give you a little bit of fill.

 

Nige,

 

You're right. Different zoom settings will produce different shapes of the shadow, as will it's orientation relative to the surface it's casting a shadow on.

 

Steve,

 

You either have no idea what you are talking about or aren't bothering to read what other people are writing or maybe a little bit of both yet you continue to go on and on. Throughout this whole thread where people said they are probably caused by the flash they said it was a shadow not a reflection. Meaning decresed density not increased.

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Tom: I do not believe that you fully read what I said, or maybe you did not understand but I thought I was clear. I'll get to that in a second.

Upon seeing the contact prints there is no doubt that the half moon is indeed a shadow unquestionably caused by flash interference.

I think that the problem I and some others had, stemmed from the scanned image. The second scanned negative image looks very much like a negative that was improperly developed. There is what most definately appears to be an area of reduced density in a line above the half moon. This is seperated from the half moon reduced density. My comment was suggesting that this upper area cannot be shadow as it is in an area that would have to be above the lens barrel shadow. If that were the case, this area could not be shadow but must be relection and therefor it should be increased density. In the contact print this does not appear and therefor the scanning produced it.

Tom; I am only trying to be helpful to a novice and there is no need to be uncivil in your responses to me. While I consider myself by no measure, an "expert", I have nevertheless taught photography and advanced darkroom technique for many years and when presented with problems by my students I try to weed out many possibilities in the hope of eventually correcting them. I do not believe that the scanned image produced an easy riddle. I do believe that the contact sheet does.

If I have taken the time to respond to the query as I hope others do for my questions, then I think it is in all of our best interests to remain amiable.

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