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BetterPhoto Q&A
Category: Scanning Photos and the Digital Darkroom

Photography Question 

algan nustekin 		 

Dirt Spots on Scanned Slides


 
  old car
old car
28-80af nikkor lens f11. fuji velvia50

algan nustekin

  
  dirts
dirts

algan nustekin

  
 
You can see a picture that I shot with my Nikon F55 using Fuji Velvia 50. One picture is my whole image; the other one is made in Photoshop by actual pixel command. As you can see in 100-percent view, there are lots of dirt (little black points) in the image. I am not complaining about the scratches but I could not understand why the little black points are there. As you can see from the summary of the file, Velvia 50 was scanned 4000dpi in a lab with Nikon Super Coolscan 5000 ed. I tried to solve this problem with several filters such as gaussian blur, median, despeckle in PS 7.0, but none of them satisfied me.
I checked some positive film images in this site and in another, but I never saw positive film scan images as horrible as mine. They are very clear and sharp images. I also checked images that I shot with a Kodakcx4300 3.2mp digital camera - more clear then my 23mp scanned image ... how can it be? I would be very glad if someone offers me some advice.


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June 22, 2005

 

Bob Cammarata 		 
 
  Test 1
Test 1
Just a slide of a lonely shad fisherman...which had been lying around on my light table a little too long.
(Scanned as-is, with a Nikon Coolscan 4000.)

Bob Cammarata

  
  Test 2
Test 2
The same slide after a little clean-up with a Q-Tip and compressed air.

Bob Cammarata

  
  Test 3
Test 3
This final image was after cleaning...and when Digital ICE had been applied.

Bob Cammarata

  
 
Algan,
First of all, when you enlarge ANY scanned image that dramatically, you will see some dirt and/or foreign material. That's a given fact. This will indeed be relevant if you are planning on making enlargements from the scanned image. For normal Web use you look OK. (The specs are hardly noticeable on the original.)
That point aside ... your enlarged example looks to me like your Velvia slide may have been laying around a while before it was scanned. Dust and contaminants tend to accumulate rather quickly ... as I've learned when I leave my slides lying around too long before storing them.
You mentioned that your slide was scanned in a lab on a Nikon 5000 ED. Does your lab clean slides before scanning? (If not, I think they should.)
If they don't, you can do it yourself with a simple Q-Tip and a can of compressed air. Brush the slide gently in one direction toward the darkest side of the image ... then give each side a good blast with the compressed air to remove whatever residual cotton hairs the brushing action may have left.
I've given this advice in the past to many slide and film users who regularly scan their photos because it works.
After this initial cleaning, examine the slide carefully on a light table with a good loupe.(An inverted 50mm lens works great as an alternative to the loupe if you don't have one.)
If you can still see a few specs after cleaning, try again ... or apply a digital clean-up program such as Digital ICE to remove the stubborn ones.
(Note: Digital ICE comes with the standard software package included with Nikon Coolscan 4000 and 5000 scanners if you own one. If you don't, your lab may charge extra for this service.)
In the attached examples you will see the difference between the same slide ... before and after a little clean-up.


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June 23, 2005

 
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