Vuescan IR Distortion

Discussion in 'Digital Darkroom' started by Dave410, Oct 12, 2013.

  1. Hello,
    I'm scanning a bunch of old Kodachrome slides with the latest version of Vuescan Professional and a Nikon Super Coolscan 5000 ED and I'm having trouble with Vuescan's Infrared Clean filter. It either creates really annoying halos and/or blows out the reds in the image.
    I started (and then aborted) this project several years ago and at that time I traded several emails with Ed Hamrick. He was very nice and very helpful, and actually changed the code in Vuescan to try to fix it, but he was never able to resolve the issue.
    I understand that IR cleaning Kodachrome slides is problematic and I may just have to decide between accurate, dirty images or clean, distorted images, but I would sure appreciate any suggestions you might have. I'll post some cropped images that illustrate the problem.
    Many thanks,
  2. Here is a dirty image with no IR cleaning. It's really not too bad considering the slide is a duplicate of a Kodachrome and is almost 40 years old.
  3. The same image with IR cleaning. No other changes to the scanning software were made.
  4. Another dirty image with no IR cleaning. Also a very old Kodachrome duplicate slide.
  5. The same image with IR cleaning.
    These are all images of duplicates of Kodachrome slides, but I see the same problems with newer, non-duplicate Kodachromes, although the blown out reds may be a little better.
  6. Just a few thoughts:
    From the first (non-cleaned) image: I believe there's a mirror in the Coolscan line, that can accumulate dust and cause those halos.
    Kodachrome is problematic with infrared cleaning, due to the multi-layer emulsion. This is aggravated by highly directional light source scanners like the Coolscan 5000ED. A diffuser may help, but will reduce light intensity, and may not even be available any more. ScanHancer is a name that comes to mind.
    I've scanned Kodachromes with my Scan Elite 5400 (first gen). It has a more diffuse light source to begin with, and also has a light diffuser (Grain Dissolver) which can swung in or out of the light path. The 5400's employment of (patented) ICE is not even allowed without the Grain Dissolver in the light path.
    Vuescan makes no restriction on it's infrared cleaning being used without the 5400's GD, I've tried both with/without, and without the GD the sharp contrast edges of images show a lot of artifacts. With GD they don't.
    Vuescan's cleaning is woefully inferior to ICE. I'll use it in some instances, on relatively clean images. But where I need more serious cleaning I use the 5400's proprietary ICE, save a "raw", gamma 1.0 tiff through the Minolta software, then use it as a Vuescan "raw file".
  7. Are these Kodachrome slides, or duplicates of Kodachrome slides?
    What are they duplicated on?
  8. Robert - My buddy shot Kodachrome slides and then sent the slides to Kodak to be duplicated so he could give me copies. I scanned the copies in this case, but I see the same issues on original Kodachrome slides.
    Mendel - I'm familiar with Scanhancer, but it doesn't work with the Nikon SF-210 slider feeder I'll need to use for all my boxes and boxes of slides. And I looked at the instructions for cleaning the mirror on my scanner -- I'm afraid I would break it and you can't get them anymore. Scary stuff!
  9. I sent those same images to Ed Hamrick this morning and he responded right away. (On a Saturday, no less.) He said he had noticed the same thing on some older Kodachrome slides and it was on his list to fix.
  10. I use a different approach, I clean the slide before scanning using a camel hair brush followed by a wipe down with a clean heavyweight microfiber lens cleaning cloth, , and have never scratched a negative or slide.
    If the preview shows specs I pull the slide, wipe it down, and try again until I get a clean scan. It actually saves time in the long run.
    Toss the microfiber cleaning cloth in the wash with a regular load to clean but do not use fabric softener then hang to dry.
  11. Charles - I'll give the lens cleaning cloth a try. I had already been brushing both sides of the slide several times with a camel hair brush, but I haven't tried a lens cloth. I have a bunch of those in my camera bag. Thanks.
    BTW, Ed said he might have a chance to work on Vuescan in a couple of weeks.
  12. Yeah I think the mirror is front silvered. The DIY instruction for cleaning suggested to almost completely break the stalk of a qtip, then clean holding it on the side of the stalk beyond the break.
  13. creates really annoying halos​
    +1 on the remark from Mendel Leisk. The halo on the first image looks very much what I had with my LS2000 before I cleaned the mirror. Be careful with that mirror: it's front-surface; do not apply pressure when cleaning. Find some instructions on dis-assembly, and you'll be shocked when you see the mirror. The lens is less problematic, being less exposed to dust accumulation.
    Next, as far as I know, you cannot use IR "spotting" with Kodachrome. Take a close look at the emulsion side of a Kodachrome slide (catch a specular reflection off a lamp): all image patterns are outlined in some kind of bas-relief, which is picked up in the IR image as "defects".
  14. After a quick scan of the disassembly, on a scale of 1 to 10, 10 being the most difficult it would be a 6 or 7 for me.
    Someone familiar with servicing electronic devices but little experience an 8 to 9.5 .
    Someone with no experience servicing electronic devices a 11 to 12.
    If you have a good command of using small hand tools give it a go.
    Its around a 4 for a Nikon tech.
  15. I suspect, but do not know for sure, that Kodak did their slide duplicates on

    or its equivalent. I had always been told that infrared cleaning didn't work with Kodachrome, so never tried it.
  16. As always, Ed Hamrick is being very helpful. He told me he would try to fix it in about two weeks and then just a few days later he asked for RAW files so he could duplicate the problem. Unfortunately, I'm on the road and it will have to wait until I get home.
  17. I wanted to clean my 5000 ED scanner, so I took it apart based on the instructions on the Pearson site. Then afterwards I saw that the mirror is accessible when the slide holder is removed, without having to take the scanner apart.

    If you look down into the slot in the scanner, you will see a pocket w/ the lens and mirror. The mirror will be more difficult to see since it is at 45 degs. If you shine a flashlight or desklamp in you will see the mirror and any dust quite well. You may actaully see the refelction of the lens in the mirror. You may want to tilt the unit at 45 decrease towards you to get a better view of the mirror.

    The mirror can be cleaned with a piece of lens tissue folded to about 1/2" width and then folded over the top of a cotton swab. I only use high grade >99.9% (HPLC Grade) methanol on all my optics. ( I bought a 1 gallon bottle at sigma chemical, that will last me a lifetime, shipping is expensive) I have never had luck with standard lens cleaning fluids. I usually have to clean 3 times each time with a new piece of lens tissue. Just be careful not to apply too much force to the swab. The mirror is coated on the outer surface, and will scratch easiley but should be ok w/ standard lens tissue w/ cotton swab. It will be more difficult to clean the lens because the access is limited. In my unit the mirror was very dirty, the the lens was clean.

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