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

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Subject: [Leica] Tiny white spots on my negs! Analysis and partial fix
From: douglas.sharp at gmx.de (Douglas Sharp)
Date: Mon Nov 21 02:29:17 2005
References: <5.1.0.14.2.20051120230012.00bdfba0@mail.2alpha.com> <6.1.0.6.2.20051121003105.121d5df8@192.168.100.42> <438195BF.10401@gmx.de>

Hi Richard,
I analysed your image - here are most of your spots - at least those 
which are around 1 pixel in size, amybe this helps to get closer to the 
problem and a possible(partial fix.
http://gallery.leica-users.org/New-Old-Pictures/1_25WhiteSpots_Difference   
Difference analysis - spot distribution
http://gallery.leica-users.org/New-Old-Pictures/1_25WhiteSpots_HPF_1  
1st iteration (pass) of Hot Pixel Fix
http://gallery.leica-users.org/New-Old-Pictures/1_25WhiteSpots_HPF_2  
2nd iteration HPF

Running HPF twice seems to get rid of a few more spots, the residual 
spots can easily be edited out with "healing brush" in PS, I think the 
analysis shows that these are minute particles, probably out of your 
water supply, a couple of microns in size which would pass most water 
filters,, the larger particles are probably airborne dust (1 remains on 
the window pane, 1 to the right of the horizontal handrail around the 
centre of the image. On a full resoluition input it would probably be 
more effective..

Processing sequence:

   1. input original image
   2. convert to RGB
   3. Duplicate
   4. Apply Hot Pixel Fix (mediachance.com DCE Tools)
   5. Select all on duplicate
   6. paste to original as layer
   7. Extract difference (100%)
   8. flatten image
   9. increase levels for display and save

This image shows exactly what HPF is extracting from your original image 
- to remove spots just run 1,2 and 4 (I ran 4 twice) - it worked wonders 
on some 1950s negs I scanned for my parents.
The result is quite interesting when you look at the distribution, 
there's a definite grid pattern which doesn't relate to the structure of 
the original image, did you flat-dry the negs on some kind of frame?.
Douglas

Douglas Sharp wrote:

> Hi Richard,
> try scanning the neg as if if it was a colour slide 1) without FARE   
> 2) with FARE,   if they persist it is the negative, and not the 
> scanner. Of course you get a negative image which will show the spots 
> even better, so you can see if they're evenly distributed. If they are 
> concentrated in one place, for example the bottom edge or towards the 
> bottom of the film strip when it was hung up to dry, it could mean 
> that the negatives went spotty during the washing and drying process  
> - perhaps fine particles of scale in the (hard?) tap water.
> Just a suggestion
> Douglas
>
>
> Richard wrote:
>
>> I seem to get more of those with Efke 100 than Tri X and HP5+, even 
>> though everything else is the same. (I developed my own using Jobo)
>>
>> At 11:08 PM 11/20/2005, 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.
>>>
>>> --Peter
>>
>>
>>
>> // richard (This email is for mailing lists. To reach me directly, 
>> please use richard at imagecraft.com)
>>
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>>
>
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Replies: Reply from douglas.sharp at gmx.de (Douglas Sharp) ([Leica] Tiny white spots Analysis and partial fix,)
In reply to: Message from pklein at 2alpha.net (Peter Klein) ([Leica] Tiny white spots on my negs!)
Message from richard-lists at imagecraft.com (Richard) ([Leica] Tiny white spots on my negs!)
Message from douglas.sharp at gmx.de (Douglas Sharp) ([Leica] Tiny white spots on my negs!)