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

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Subject: [Leica] Tiny white spots Analysis and partial fix,
From: douglas.sharp at gmx.de (Douglas Sharp)
Date: Mon Nov 21 02:35:26 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> <4381A176.5070102@gmx.de>

OOPS!
just looked at my analysis again - the dark lines correspond to the 
lighter areas which are, of course the same colour as the spots, silly 
me!!!!
Douglas

Douglas Sharp wrote:

> 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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>
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Replies: Reply from douglas.sharp at gmx.de (Douglas Sharp) ([Leica] Tiny white spots Analysis and partial fix Correction)
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!)
Message from douglas.sharp at gmx.de (Douglas Sharp) ([Leica] Tiny white spots on my negs! Analysis and partial fix)