Scanning Dark Images

Discussion in 'Scanning and Scanners' started by RattyMouse, Aug 12, 2018.

  1. RattyMouse

    RattyMouse Member

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    My most recent scans of film showed some very serious defects in image quality, that I initially thought was due to a problem with my development. As seen in the example below, there are all kinds of white specs on the scan (and every shot in this roll; similar lighting). Thankfully, I developed a second roll in the same tank and these images are from during the daytime, without much darkness at all. No spots at all on this roll. Same film, TMAX400, and the same developer, obviously being in the same tank at the same time.

    So, I'm guessing that this must be some sort of scanning defect. Is my scanner dying or is this the result of some software error that I am not aware of? SilverFast is a very confusing piece of software so I'm not that great at it.

    Thank you for your comments!

    [​IMG]
     
    Last edited: Aug 12, 2018
  2. shutterfinger

    shutterfinger Subscriber

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    1st suspect: dust from the drying enviorment.
    2nd. suspect dust in the scan path, under side of the scanner glass, mirrors, lens, sensor. Do not remove the sensor in any scanner for cleaning as its exact position must be reestablished to get accurate scans without distortion.
    The dust is likely micro fine and not visible to the eye.
     
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    RattyMouse

    RattyMouse Member

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    I developed 3 rolls of film in this tank. All films have been in the same condition. Only the film showing dark scenes shows these dots.
     
  4. shutterfinger

    shutterfinger Subscriber

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    Have you inspected the film with a high power loupe to eliminate it? Lighter tones can be masking the dust specs.
    What scanner? I've never known of a scanner or its software to add such to the scan unless you have ICE enabled on a silver based film. In post 1 you state its a silver based film.
     
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    RattyMouse

    RattyMouse Member

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    I don’t have a loupe. Scanner is a Plustek OpticFilm 120.
     
  6. shutterfinger

    shutterfinger Subscriber

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    Got a 50mm (35mm SLR) lens? With the aperture wide open look through the rear of the lens at the negative on a light box. Focus distance is an inch or so above the film. Other focal lengths may work also.
    Don't have a light box, open a blank text document full screen.
    Use canned air to blow out the scanner. Avoid shacking the canned air while in use.

    I learned to scan with Silverfast Ai6, I only have Silverfast SE8 now.
     
    Last edited: Aug 13, 2018
  7. Wallendo

    Wallendo Subscriber

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    I suspect you have drying marks on the negative and would recommend rewashing the negative. The dark images on your scan correlate to light portions on your negative. My experience is that my scanning process (OpticFilm 8200i and VueScan) tends to magnify drying marks, dust and fingerprints when scanning light negatives. Darker parts of the negative (light areas on the scan) and areas of high contrast tend to cover up such blemishes. It appears that there may actually be a partial fingerprint along the bottom of the image near the right side.

    Using photoshop, the noise can usually be removed by adjusting the gamma of the image (I use the levels control for this) but would cause a loss of shadow detail which would significantly change the image.
     
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    RattyMouse

    RattyMouse Member

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    Why would there be drying marks on this roll of film and none on the other two rolls? Surely drying marks appear on all types of film, not just ones containing dark images. This confuses me.
     
  9. Wallendo

    Wallendo Subscriber

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    I suspect that whatever you are seeing is in fact present on the other rolls but not seen with the scanning process. I have noticed on rolls I have shot using Sunny 16 (or just wild guesses) that marks similar to this are only identified on significantly underexposed frames while properly exposed frames are clear. I suspect that the scanner/software combination, when trying to extract images from areas of very low negative density tends to amplify irregularities on the negative. I have multiple scans of my own which suffer from the exact same defects as you noted on your scan. Sometimes rewashing the negative helps (or at least moves the marks to new places).
     
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    RattyMouse

    RattyMouse Member

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    OK, thank you. I have purchased pure water to use during my washing stage to see if this helps with the situation. I dont know if the film I have left to develop has as much dark area as the roll that showed this problem initially.
     
  11. DWThomas

    DWThomas Subscriber

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    In my experience, very thin areas of a negative, especially a generally thin negative, will result in the scanner (and software) trying to make detail out of whatever variations it can find. That can lead to seeing every microscopic scratch, dust particle and smear in existence showing up. (Try scanning a blank hunk of leader sometime with the scanner playing 'automatic.') On a more "normal" exposure of a typical daylight scene, the microscopic physical defects are suppressed because their densities are outside of the range for the important parts of the negative.
     
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    RattyMouse

    RattyMouse Member

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    I like your theory, which means that what I am seeing is normal. However, I need to be able to scan these dark negatives so how to tell the software to tone down the amplification of the signal? I am using SilverFast AI Studio 8.
     
  13. DWThomas

    DWThomas Subscriber

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    I use Vuescan, so can't give any step by step, but in general if you set the white point and black point in whatever sort of manual mode is available you can move the scan range around and expand or contract the range. (At least some, obviously there is no infinite variability.)
     
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    RattyMouse

    RattyMouse Member

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    I'll look into this. Thank you very much.
     
  15. jeffreyg

    jeffreyg Subscriber

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    I use SilverFast Studio8 as well. It has a number of adjustments that you can use, also profiles for different films which you can use or use one film's profile with a different film. They also have a program that can be followed step by step if so desired. I generally do very little editing with the scanning software. I prefer to make minimal adjustments, enough that there is no clipping and the image looks reasonably good and then do the editing in PhotoShop or ON1 PhotoRaw 2018. I try to make the best negative possible and do as little editing that is necessary. I tend to do what I would do in an analog wet darkroom.

    http://www.jeffreyglasser.com/
     
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    RattyMouse

    RattyMouse Member

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    I make virtually no use of SilverFast's hundreds of adjustments. After I set my film size and bit depth, I scan a preview, select the entire image and then hit auto adjust of levels. After that, I select the resolution and then do my final scan. Nothing more.
     
  17. jeffreyg

    jeffreyg Subscriber

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    I'm not sure using auto adjust is the best way to go. I would tend to do some manual adjusting either with the sliders and/or curves. Select the bit depth and resolution before the preview then adjust to avoid clipping whites and blacks then the mid tones so you are reasonably close. Then scan and tweak in PhotoShop or whatever software you use for editing. Using "auto" is generally not recommended IMOP.
     
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    RattyMouse

    RattyMouse Member

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    I dont use photoshop post scanning. I have Lightroom which gives me what I typically need from my scans. I try to poke around SilverFast and see how to adjust whites and blacks. It sounds simple to most but not something I have dealt with before.
     
  19. jeffreyg

    jeffreyg Subscriber

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    It is worth playing around with because it is not difficult. You can also adjust exposure + or -. Once you are close Lightroom can do the rest. If it is not on the scan it won't be there. All the images on my website are from scanned negatives 2 1/4, 4x5 and two from 35mm Ilford Delta 400 and HP5 developed in ID11 scanned on an Epson 4870 that is about 12-13 years old.

    http://www.jeffreyglasser.com/
     
  20. shutterfinger

    shutterfinger Subscriber

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    When I got a Microtek 8700 Pro it shipped with Silverfast Ai6. All seemed confusing at first so I loaded a negative (color) that printed good at the local lab and did a full auto scan at 600 dpi for my reference scan. Next I went to full manual mode and did a base scan at 600 dpi with the negafix set to the film type for that negative. Then I started with one adjustment at move it in 10% increments, making a scan after each adjustment and comparing to the base scan for color accuracy and detail loss or gain. After going through each adjustment by themselves I started combining two adjustments where I found the limits of adjustment less than with one and by the time I got to three adjustments together I understood how they worked singularly and together. This took about 18 hours spread out over 3 or 4 evenings after work. I can take any unfamiliar scan software and within an hour or two get excellent results from it. Scan for the best detail from the negative, use post to adjust it for the best image.

    Get a bottle of PhotoFlo, use it in the final rinse. 1/4 to 1/2 cap full should be enough to get the water to sheet off without leaving marks or mineral deposits. The amount you need will depend on your water supply and tank volume.

    +1 for post 11.
     
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    RattyMouse

    RattyMouse Member

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    I do use Photoflo. I'll also try out your scanning exercises and see if I can learn that way. Some adjustments seem to do almost nothing so I'm not sure what they are meant to do. The names do not give any indication.
     
  22. shutterfinger

    shutterfinger Subscriber

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    How do you dry your film?
     
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    RattyMouse

    RattyMouse Member

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    Hang in up in the basement after a dip in 0.5% Photo Flow.
     
  24. shutterfinger

    shutterfinger Subscriber

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    Make a cover for your drying area. 3mil to 6 mil plastic that extends 10 to 12 inches either side of the hanging point will protect a 36 exposure strip of 135 film/ roll of 120 film.
    The specs you are seeing in your scan is the fine particles that fall off the ceiling above the drying area as the occupants move about on the floor above and or the fine dust in the air from a central air circulation system (air condidioner/ heater). Textured ceilings are some of the worst.
    Eliminate air flow in the area while the film is drying also.
     
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    RattyMouse

    RattyMouse Member

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    Point noted. Thank you.
     
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