Archived posting to the Leica Users Group, 2005/11/21

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Subject: [Leica] Tiny white spots on my negs!
From: ajt at mrps.demon.co.uk (Tony Terlecki)
Date: Mon Nov 21 04:16:37 2005
References: <5.1.0.14.2.20051120230012.00bdfba0@mail.2alpha.com>

On Sun, Nov 20, 2005 at 11:08:08PM -0800, Peter Klein wrote:
> There were a lot of miniscule white spots on my Neopan 400 negs from San 
> Francisco.  I don't usually get these, at least not with Tri-X or 
> T400CN.  This picture is a 1:1 snippet of the "vertigo" picture from my SF 
> gallery, but scanned on my Canon FS-4000us at 4000 dpi.  The spots are 
> most 
> visible on the windows at the right, but they are actually all over the 
> whole negative.
> http://gallery.leica-users.org/album186/1_25WhiteSpots
> 
> The negs were developed at the same lab I usually use.  What is all that 
> white crud?  Grain aliasing?  Improper fixing?  Chemical residue?  Seems 
> too prevalent to be dust.  I couldn't see anything with my 22x loupe.  But 
> I could see many of the same spots both on the low-res Noritsu scans from 
> the lab, and on a couple of pictures I rescanned myself at 4000 dpi. So 
> something on the negative is making those spots.
> 
> I know better than to use ICE (FARE actually) with real B&W, so that isn't 
> it.
> 

I get these spots all the time when scanning HP5 souped in ID-11. My
processing is immaculate so I know it's nothing to do with the film or
chemicals.

I use a Nikon LS-4000 and my guess is that it is the light source of the
scanner which is causing the problem. Mine has a collimated light source
and shows up stuff that just would never appear when using a diffused
light source. Usually, this is exaggerated grain and the "micro-blocking"
(don't know what the official technical term is) that you are showing in
your image.

The problem goes away when I choose another film/dev combo (e.g. Tri-X
and DDX) but I'm not willing to give up my standard combo for the sake
of getting good scans (I still mostly do wet prints).

In short my guess is light source combined with the grain structure of
that particular emulsion is the cause. Shows up even more the second you
try and do any sharpening.

-- 
Tony Terlecki
ajt@mrps.demon.co.uk

In reply to: Message from pklein at 2alpha.net (Peter Klein) ([Leica] Tiny white spots on my negs!)