vertical lines on negatives

<p>I am new to medium format. I have gotten a few rolls back from my 500cm with lines down the middle of the prints. i checked and the lines are also on the negatives. they are vertical lines only and appear most right down the middle of the frame. what could be causing this? i have tried 2 different labs and some rolls have had the same problem. i have 2 different film backs, but have not tried testing to see if it is from one or the other. although a couple rolls i have gotten back had no problem at all. i posted i sample below...<br>

thanks for the help<br>

Steve</p><div></div>

<p>i just noticed that not all of the negs in a roll have the line, but it seems that when the line starts, it continues on to the next ones...</p>

<p>Obvious scratch lines.<br>

Could be from processing, but check all of your backs for grit and dirt (more in particular the film gate, the little rollers above and below the gate), and clean them thoroughly (hard brush).</p>

<p>i did just notice one small burr on one of the rollers. should i hit it with fine emery cloth? even so, there are some with smaller lines on the sides of the big scratch...</p>

<p>actually in the photo posted, there is a smaller scratch next to the big scratch. i would think the burr would only contribute to one scratch because it is very small</p>

<p>A thought.....<br>

Just to be sure, before fooling around with the film back, I would take another roll to sacrifice and either process yourself or find another lab to develop the film. <br>

I process my own film & have several Hasselblads, film backs and other stuff and haven't had this happen.</p>

 

<p>Burrs on a roller wouldn't make smooth lines like that. They would make evenly spaced scratches that are in line with each other (more like a dotted-line) as the burr would only make contact once per revolution. Lines like that would come from somewhere that is in constant contact with the film, such as the pressure plate of the camera or one of the guides in the film processor.</p>

<p>You have used two labs, so the next step should be to identify the back used when the lines appear.</p>

<p>roger that. i inspected both of them, and the small burr is all i noticed. the back plate seems fine...so was the scratch made before or after processing, im not 100% sure. Anyone in the New Jersey area who can recommend someone to process the film? I do not really have the $ or space right now to get into it myself...</p>

<p>The only thing the film comes in contact with when run through the magazine are the two small rollers below and above the film gate.<br />A bur on one of them could cause a continuous scratch, if the roller is stuck, doesn't roll.<br />So check that too.</p>

<p>Apart from that, you should indeed try to smooth the roller again. If not the cause for the continuous line scratch, it can still cause a repeating pattern of short marks, as mentioned by Cory.</p>

<p>The pressure plate never touches the film. So not a possible cause.</p>

<p>By the way: you can check for mechanical damage like this without having to process film. Just run it through the back, and inspect the film unprocessed.</p>

<p>"The pressure plate never touches the film" - in a 120 film back.</p>

<p>Quite right.<br>

I hadn't thought about 220 backs. Thanks for the correction.</p>

<p>I'm having a similar issue on some of my film, tried two backs and it's only happening with one of my A120s -- does this look like a plate issue or could it be foam somewhere in the back? (I know there's a lot of dirt in the perimeter of this image). Thanks.</p><div></div>

<p>Molly, I've just seen your post. I take it that you mean the vertical dark red area at the bottom middle of the picture area? This looks very much like a light leak or possibly an internal reflection rather than scratches on the film.<br>

You could try putting some black tape over the dark slide slot on the suspect back and running a film through. If the fault is still there, it may well be the result of an internal reflection rather than a dodgy back.</p>