odd streaks on Pentax K1000 negatives

[chapelcross]

I've begun reusing my old (1983) Pentax K1000 recently, and find occasionally that I get streaks along one edge of

the exposed from as in this scanned example:

 

http://www.flickr.com/photos/chapelcross3/2744095416/

 

I hadn't noticed them before, and can't decide whether the streaks are a form of lens flare or reflection, or light leak.

With colour film, the streaks themselves are coloured and vaguely spectral.

 

The lenses I use are Super Takumar 50mm/f1.4, 105mm/f2.8, 24mm/f3.5

 

Does anyone have ideas?<div></div>

[radfordneal]

Sorry if this is too obvious... but have you checked to make sure that this is present on the negative itself? Ie, could this

be a problem with your scanner?

[chapelcross]

Thanks for the answer/question, which hadn't occurred to me. But yes, the streaks are on certain individual frames

of strips of negatives, both black and white (Ilford FP4, Delta 400, Pan F...) and colour (Fuji Sensia, Fuji Provia).

[evan_goulet]

That looks like your film is not flat in the film holder of your scanner. I get them occasionally when the film is curved at the end of a film strip. I use an Epson V700 scanner and the film holders are not good at holding the the first and last frames on a strip of negatives flat.

[rivi]

If these are on the negs, have a look at the light seals on the back door of the camera. Depending on material they may have aged, letting some light through.

[evan_goulet]

Keep in mind that a light leak will show up as bright lines/areas on the positive image. These marks are dark on the positive image. I am still betting on refraction of light due to curled film in the scanner.

[rivi]

In understood from the second answer that it is on the actual carrier, and so has nothing to do with scanning. But I may have misunderstood that.

[chapelcross]

I've now had a chance to check the original negative and scanner, and to rescan it.

 

The negative itself is too dense to see the rather subtle variations by eye, so I was wrong about confirming that it was on the negative, at least for this particular frame.

 

As Evan suggested, the sample frame I provided WAS the end of a film strip; I haven't yet checked whether all the other cases of streaks were, too.

 

After sitting under weights for a few months, the negatives are flatter. A rescan yielded an image free of the original streaks, even after using Photoshop to alter grayscale significantly.

 

Incidentally, I use a Canoscan 4400F, which has an unimpressively delicate plastic film holder.

 

So - thanks, Evan; your diagnosis fits.

[evan_goulet]

Hey chapel, glad to hear it worked out. My cure for this phenomenon is to place the negatives into a plastic negative file page, and then place that page inside the cover of a large book (I recommend the CRC Handbook of Chemistry and Physics!). Then I place that book on top of my cable box by the TV (with the cover that holds the negatives down), because it puts out a lot of heat. This way, the full weight of the book is on the negatives. The heat shortens the relaxation time for the polymer base. When it has been at least 12 hours, I take the book off the cable box, and then I place the negatives inside the opposite cover (cool side of the book) and place that side down on a table to allow the negatives to cool under the weight. After about 30 minutes of cooling, they are really flat.