I sometimes have a problem of very thin white lines across my prints. When I inspect the negative, there seems to be a very thin black line running across. I keep my camera clean. This problem is ever only on a few frames and never down the whole length of the film. I develop my own films and use a bulk loader. Any tips would be welcome to get rid of this problem.

-- David Owens (david@rador.co.uk), December 18, 1999

Answers

It's possible your bulk loader or the film cassettes have some grit embedded in the felts. I used to have the loader that had two felts at the film opening, and got rid of it for that reason. Now I use the type that rotates an inner drum to provide a passage for the film without touching it.

Are you using a squeegee to remove excess water from the film before hanging it up to dry? They are very prone to scratching film. I hold the roll at both ends and give it a sharp snap to fling off the water, and then hang it (after treating in Photo Flo) without touching it any further.

All of these kinds of scratches will be along the length of the film. If yours are across the narrow way, something else is going on.

-- Tony Brent (ajbrent@mich.com), December 18, 1999.

Bulk loading is often known as "bulk scratching."

Ditch that thing; it just isn't worth the risk.

Next, clean the pressure plate of your camera with some lens cleaner and tissue, taking care to blow away any lint left behind.

And the next step is that if you use a squeegee after the wetting agent, _stop it_.

-- John Hicks (jbh@magicnet.net), December 18, 1999.

I bulk load without a loader, and never have this problem as a result. The trick is to get a feel for approx. how long the number of frames you want on the rolls is. I use the full stretch of my arm, snip the film, and then take the end and start rolling it onto the cassette like I'm rolling a cigarette with a really long piece of paper. Never have problems this way, but can only judge within 2-3 frames just how long the roll will be. I can load about 10 rolls in 15-20 minutes. shawn

-- shawn gibson (s_g@stu.wdw.utoronto.ca), December 19, 1999.

I may be taking too naive a view on this, but I would expect a grit between the felts of a bulk-loading machine to cause a scratch in the emulsion, thus a white line in the negative, and a black one positive. The same actually applies to squeegee marks.

I did read in a book a couple of years ago that such white lines in prints could arise as a consequence of static electricity (little discharges taking place at the film cartrige opening) when the film is rewound too quickly, mainly under unfavourable temperature/humidity conditions.

That aside: Besides the bulk-loading machine, the camera itself might be the culprit. And finally, it might be your cartridges.

To exclude the candidates one by one, run some tests:

1) Check whether the line is always at the same distance from the film border. If it is, this is a strong hint for a mechanical problem (i.e. the grit in the loader, the camera, or a cartridge). I would expect some variation in that distance if static were the cause, because the discharges are rather unlikely to alway occur in the same place.

2) Use films from a different source. If the problem persists, it is not the loader.

3) If you leave one or two frames blank at the end of a roll of film, do these also exhibit the line? If so, it is not the camera! (Unless you are using one of those cameras that fast forward the whole film when loaded.)

4) Get some new cartridges. (If you wish to stick to self-loading, you will need them anyway sooner or later.) If they solve the problem, ...

5) The squeegee should be easy to eliminate by not using one.

This should allow to identify the source. Finding a solution might be particularly difficult when it is the camera or the loader.

-- Thomas Wollstein (thomas_wollstein@web.de), December 20, 1999.

"I may be taking too naive a view on this, but I would expect a grit between the felts of a bulk-loading machine to cause a scratch in the emulsion, thus a white line in the negative, and a black one positive."

Actually, undeveloped film is pressure sensitive. Mechanical stress can make unexposed halide developable. So a piece of grit can make a black mark without an actual scratch. Folding a crease will too.

-- Tim Brown (brownt@ase.com), December 20, 1999.

Tim,

In principle, you are of course right. I have seen such pressure marks, but they were all much broader than scratches/static marks, and had diffuse boundaries. When a piece of grit is embedded in the felt, it will be pressed into the emulsion and will drawn along the whole length of the film. I can hardly imagine this to cause a uniform thin line of pressure-induced density. I think a groove, or scratch, is much more likely.

What I meant by "too naive a view" is this: I do not think that it is entirely impossible that a slight scratch that fails to remove all of the emulsion (so there is no transparent line on the negative and consequently a black line in the print) might cause a white line in the print because the damaged film surface is less transparent than a neat one. Come to think of it, this might even be more likely than static. The characteristics should be pretty much those mentioned under item 1) in my previous post, and the path to finding the problem remains the same. It might be possible to save the negatives with such a mark by filling the grooves with a varnish with an appropriate refractive index. Now that you got me to think about this again, I even remember that for such purposes, Tetenal offers a product called Repolisan. Bath the negative in this, and scratches of that type should become invisible.

-- Thomas Wollstein (thomas_wollstein@web.de), December 22, 1999.