Can you see it on the negative? Can you see it on the contact sheet?
It is slight enough that it would be very hard to see. If it is in
the negative then I would suggest slight over agitation in the film
developing process.
Alan Brown
On Thu, Jul 29, 2010 at 10:33 AM, Ken Norton <ken@xxxxxxxxxxx> wrote:
>> I'm trying a new enlarging lens (Nikkor 50mm f/2.8N) which has amazing
>> resolution, but for
>> some or other reason I'm getting weird light falloff, not in the
>> corners as such, but
>> in parallel to the long edges of my prints. This image shows it clearly:
>
> I've seen this twice before. One was because the enlarger head didn't
> have even lighting--this can get tricky, and the other time was when I
> tried going too low on the enlarger to make a tiny print and a inverse
> vignetting resulted.
>
> I primarily use a diffusion head on my enlarger, but also have
> columinated heads too. The inverse vignetting occured not with the
> diffusion head.
>
> Hmm. Something that MIGHT be happening. Remove the light head of the
> enlarger and look straight down through it with your typical film
> holder in place. Is the film holder bright reflective? If so, there is
> backscatter which ends up causing an uneven lighting as this reflected
> light bounces back up into the head which then comes back down in a
> pattern that could result in wave shaped illumination. Remove the
> holder and look further down. Is there anything bright reflective
> inside the bellows are on the lens-board? If the lens board is
> reflective, the light bounces back to the film and underside of the
> holder. Usually, though, this type of reflectance below the film just
> results in lost contrast. These issues with reflections inside the
> enlarger are more likely when using small-format films inside a
> large-format enlarger.
>
> AG
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