Dynamic Range Issues (I think)

All the problems with Plustek film scanners

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Joined: Sat Jun 02, 2012 3:58 pm
Scanner: OpticFilm 7600i
SilverFast Product: SE

Dynamic Range Issues (I think)

Postby Barryng » Sat Jun 02, 2012 5:07 pm

I just purchased an OpticFilm 7600i scanner and am using it with SilverFast SE ver 8. I have thousands of mostly Ektachrome slides taken over the past 42 years and want to digitize them so the many memories and experiences they contain can be reasonably accessible to my family and myself. All these slides have been kept in dark air conditioned locations so their cleanliness and color saturation still appears to be excellent. My expectation (maybe naive) is to be able to convert each slide to a JPEG that would display on a monitor or HD TV with the same quality an equivalent photo taken with good quality digital camera would provide. I think this is reasonable as each slide contains much more information than even my 12 MP Nikon D90 includes in each frame and the photos taken by the D90 are outstanding when viewed on a good quality 24" monitor. In other words, I think it is reasonable to expect that color accuracy, detail, and dynamic range of the digitized image would be about the same as would be visible if I projected the slide to an equivalent size on an appropriate surface.

Contrary to this expectation, the slides I initially scanned have produced unacceptable images. By chance, I picked some slides taken indoors using an under powered strobe and poor lighting. However, even in the under illuminated areas of the pictures, good detail and accurate color can be easily seen when I project or view the slide. The scanned version of the slide is overall dark in spit of my best efforts to adjust this. Worse, the details in the darker areas is almost completely lost.

I noticed even in well exposed slides the dynamic range is poor. I have a slide taken outdoors on a bright day with very even lighting. There is scenic terrain and natural structures in the near background and my new 1979 red Datsun 280ZX is in the foreground. Although the scanned image is generally well exposed, the red car is much darker than in the original slide. I can correct one but not the other. Photoshop w would probably give me the control to properly expose everything but it becomes just too time consuming to Photoshop hundreds of slides.

Is this just a matter of slide scanners not having sufficient dynamic range to truly clone the image?

As an experiment I tried duplicating the slide using an old Bower "Digital Duplicator' I had for many years for an old Canon G3 and never used. Although the quality left something to be desired it was still better than that I was able to achieve using the OpticFilm 7600i/SilverFast setup.

Overall would it be a better, faster and higher quality solution to buy a slide adapter for my D90 and simply use that to duplicate my slides?

Any thoughts from those experienced with slide scanning would be appreciated. I was probably being ignorant but I truly expected the digitized images from a $300 machine to be a much a higher quality reproduction of the slide than I have been able to achieve. Think about it, a modern digital camera can take a high quality picture essentially instantaneously, so why can't a slide scanner due the same? Isn't it essentially just taking a picture of the image on the slide?

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Re: Dynamic Range Issues (I think)

Postby LSI_Ketelhohn » Tue Jun 05, 2012 4:26 pm

Dear customer,

Did you activate MultiExposure?
That is a special SilverFast feature to enhance dynamic range and especially enhance dark areas of images.

Also make sure you set the highlights and shadows.
You can do so either using the image auto adjustment or manually using the Pipette tool.
moving the highlights and shadows markers in the histogram is also possible.
They should be located at the beginning and end of the curve.

In most cases a dedicated film scanner will offer better results than using a digital camera.

kind regards,
Arne Ketelhohn.

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