International Stereoscopic Union


Scanners for Stereo Slides

By Ray Moxom

The basis of this information was an article which was first published in the January 2002 issue of 3D WINDOW - the Bulletin of the Sydney Stereo Camera Club Inc., Sydney, Australia (Club Website:

Prices in this article relate to the cost in Sydney, Australia then. The approximate exchange rate at the time of writing was 1 US Dollar = 2 Australian Dollars. Prices and price relativities vary considerably in different markets.

The film scanner market is rapidly developing with new models being constantly released - however all of the scanners in these pages remain good tools for the job, but are increasingly available in the used marketplace at considerably reduced prices.

If you have a slide scanner already, but don't know how to use it with your stereo slides, be sure to look at the Carrier Adaptations section! Or, if you have adapted your scanner carrier in a different way, let me know, so I can add it!

It is hoped to add new scanner models as reviews become available.


Why would you want to scan your stereo slides?

Here are a dozen reasons for converting your 3D slides into digital images. I am sure that you will be able to think of many more:

1. Make large coloured (non stereo) prints of 3D slides for framing.

2. Make small coloured (non stereo) prints to give to family, friends or to someone who may be the subject of one of your stereo slides.

3. Produce stereo cards for viewing in a Holmes type viewer (colour or black & white).

4. Produce postcard size colour stereo pairs for viewing with a View magic or ScreenScope Viewer.

5. Produce black & white stereo pairs for publication in newsletters or magazines.

6. Produce black & white mono images for publication in newsletters or magazines.

7. Produce stereo pairs for emailing to friends and colleagues or for uploading to Internet web pages.

8. Produce stereo anaglyphs.

9. Produce stereo pairs for storing and display on a computer.

10. Archive high resolution images on a CD ROM for use in creating a duplicate image in the event of the original being lost or damaged.

11. Computer manipulate the scanned images to edit or correct the original images and/or create special effects.

12. Add titles to scanned images.

An example of a title slide made from a scanned image

All of the scanners mentioned in this article are capable of scanning colour or monochrome negatives and turning them into positive images.

Do any of these applications interest you? If the answer is yes, read on!


The basic types of scanners

In the list on the Why would you want to scan your stereo slides? further above, the last three items:

10. Archive high resolution images on a CD ROM for use in creating a duplicate image in the event of the original being lost or damaged.

11. Computer manipulate the scanned images to edit or correct the original images and/or create special effects.

12. Add titles to scanned images.

will involve outputting the scanned digital images back to slide film. As very few (if any) of our members have a film recorder connected to their computer, this will need to be done via one of the labs that offer this service or by photographing the image off the computer monitor.

For home applications, the main options for scanning stereo slides are:

Epson 1640SU Photo -
a flatbed scanner with film scanning capability
Nikon Super Coolscan 4000 ED
a dedicated film scanner

The photos above are a bit deceptive. The flatbed scanner is 289 mm (11.4") wide while the width of the film scanner is only 93 mm (3.7").

As a general rule - dedicated film scanners manufactured by the likes of Nikon, Canon, Kodak, Minolta and Polaroid will give superior results in terms of true resolution and optical density when compared to e January 2, 2006 pability. However, for many application the flatbed scanner option will be adequate to the needs of stereo workers.

Slide film has greater optical density than negative film or prints. Optical density is the term that is used to rate the detail to be found in shadows and highlights. Dedicated film scanners generally have superior ability to extract the shadow and highlight detail from colour slides.

The resolution that you require in the finished scan will depend very much on what you intend to do with the scanned image. If you want to print high quality A4 or even 10" x 12" coloured images from your scanned slides, then your scanned image needs to be of fairly high resolution. On the other hand, if all you require are images to email to friends, then your need will be for relatively low resolution images.

Even if you only require low resolution images, there are advantages in having a high resolution scanner. David Stuckey, who is skilled in this area, advises that the idea is to scan at the highest resolution available, do any editing and only then (if necessary) should you reduce the resolution to the size that you need.

Care needs to be taken in reading flatbed scanner specifications. While the manufacturers of dedicated film scanners tend to only quote the 'optical resolution' of the scanner. The same manufacturers frequently quote software interpolation resolution for flat bed scanners. When comparing scanners only look at the 'optical resolution'. Resolution is further confused by a form of 'hardware interpolation' that is now being used on flatbed scanners with film scanner adaptors.


Flatbed Scanners with Slide Scanning Capability

Flatbed scanners with film scanning capability vary considerably in quality and price. A simple mask can usually be made from opaque 2 to 3 mm thick plastic or thick cardboard with a cut out to take a stereo slide. While in some cases mask may not be necessary, they generally make it simpler to scan slides in standard stereo mounts. Mask can also improve the quality of the scan by reducing unwanted reflections during the scanning process.

Up until only a few years ago flatbed scanners with a large illuminated transparency lid were one of the main option for scanning stereo slides. These scanners tended to be very expensive and 5 years ago a reasonable quality unit would have cost in excess of $2,000. In skilled hands these scanners are capable of producing very good results. David Stuckey has had one of these scanners for over 5 years. David's skill in scanning and editing images has resulted in the high quality of the colour images in the 2000 and 2001 Southern Cross catalogues.

The more recently available low end flatbed scanners with built in film scanner have a small illuminated panel built into the lid and come with a slide and strip film adaptor. One example is the Canon D660U which is a 1200 x 600 dpi scanner with a built in film adaptor unit. In film scan mode the optical resolution is 1200 x 1200, however I understand that this is achieved by a very slow double pass system.

The CanonScan D660U which was released in 2001 is available in Sydney for about $250.

The flyer for Canon's higher spec D2400UF scanner (mentioned below) boast "a Super Galileo Lens with high speed six element wide aperture lens with aspherical elements that ensures that light converges at a single point. To my cynical mind, this implies that cheaper scanners have chromatic aberration problems.

While Canon D660U scanners may be a lot of fun, the image quality may not satisfy the serious stereo worker.

Among the high end flatbed scanners with built in film scanners, the CanonScan D2400UF, mentioned above, with a claimed 2400 x 4800 optical resolution (using 'hardware interpolation') is one of the higher spec scanners in this group. The D2400UF comes complete with a film adaptor and sells for about $750 to $800.

The Canon D2400UF can scan up to 4 inch x 5 inch negatives or transparencies.

The Epson Perfection 2450 Photo Scanner  has a larger 4" x 9" built in transparency unit

Epson have recently released their Perfection 2450 Photo Scanner with the same resolution as the CanonScan D2400UF. However, the Perfection 2450 has a larger 4" x 9" built in transparency unit and more advanced and faster USB 2.0 and IEEE-1394 (FireWire) connectivity. This scanner, which sells for about $1,000, is considerably faster than the Canon D2400UF.

The now superseded Epson 1640SU Photo is a popular high end flatbed scanner with built in film scanner and has the ability to scan images up to 4" x 5". The replacement 'Epson Perfection 1650 Photo', at a competitive $450, only has 35 mm film scanning ability. However, it is possible to purchase the standard (non film scanning) Epson Perfection 1650 with an optional 4" x 5" Transparency Unit. Epson 1640SU and 1650 models have 1600 x 3200 optical resolution (using 'hardware interpolation'). The Epson Perfection 1650 with the optional 4" x 5" Transparency Unit is said to be the better option for scanning stereo slides.

Hewlett-Packard and other makers also market a similar range of scanners to those from Canon and Epson.

Unlike most of the other scanner manufacturers who have the light source for their film scanning devices built into the lid, Hewlett-Packard's HP 5470c (shown at right) has a separate light source which is put in place when film scanning is required.

HP 5470c flatbed scanner with and without its slide scanning attachment in place

With all of the flatbed scanners mentioned above, there is a need to scan your stereo slides through glass. Some say that the glass reduces the quality of the scan.

Agfa and Microtek (shown at right) have high end flatbed scanners with the ability to scan transparencys without any glass in the scanning path. This is achieved by using dedicated film scanning drawers.

This type of scanner tends to be fairly expensive and their film scanning specifications are not a match to the dedicated film scanner.

My personal situation is that I have had a 1200 dpi flatbed scanner for a few years and this scanner fills my needs for scanning photographic prints.

However, it does not have a slide scanning ability. What I needed was a scanner to scan Nancy's and my stereo slides. I was seriously considering the CanonScan D2400UF and asked for advice from a number of people including members of the 1,000 strong world wide 'Photo-3D' email discussion group (information about Photo-3D is in the box below). I particularly valued the advice and help from Max Hem (Melbourne), Ted Kraegen & David Stuckey (Sydney), David Kesner & Shab Levy (USA) and Bob Aldridge (UK). After I made my purchase I received useful comparative test information from Colin Edwards (UK).


The Photo-3D e-mail Discussion Group

For information about Photo-3D, or to subscribe to this free e-mail group, log on to this Internet Website:


Dedicated Film Scanners

Nikon Coolscan IV ED Canon FS4000US Kodak RFS 3600

Acer ScanWit 2740S

Minolta Dimage Scan Dual II

Polaroid SprintScan 4000

Dedicated film scanners are made by a number of manufacturers and some of the bigger companies have several scanners with different capabilities. Prices vary from under $500 for the prime 1800U to over $3,000 for top of the range models. As a general rule, all but the lowest cost film scanners will outperform the best of the flatbed scanners with built in film scanning capability.


Prime 1800U

Following are some comments from 3D workers who have used both flatbed scanners with slide scanning ability and dedicated 35mm film scanners.

Max Hem (Melbourne) and Bob Aldridge (UK) both have Epson 1640SU Photo flatbed scanners with film scanning capability. They both also have 35 mm film scanners that they use for scanning their stereo slides. Max has a 2,700 dpi Nikon Coolscan III (now replaced by the 2,900 dpi Coolscan IVED) and Bob has a 4,000 dpi Polaroid SprintScan. They both prefer the results from their 35mm film scanners.

Both Max and Bob advised that if I ever intended to output an edited scanned slide back to film, then I should dig deeper into my pocket and buy a 35 mm film scanner.

Colin Edwards (UK) compared the Canon 2400UF flatbed scanner with the Minolta Dimage Scan Dual II 35mm film scanner using identical negatives. Colin concluded that while the Canon 2400UF Scanner has great flexibility it does not, from his results, deliver anything like the 2400 dpi claimed definition and it will not prove a competitor to a dedicated 35mm film scanner in definition or colour balance - Caveat Emptor.

The flatbed option would have been adequate for all of the tasks, other than items 1, 10, 11 & 12, on the list at the beginning of this article. However, after researching the various scanners on the Internet as well as having several email discussions with overseas users and some personal telephone discussions with Australian users, I concluded that for my needs a film scanner was my best option. I also concluded that the film scanner that best met my needs in terms of quality, features and price was the Nikon Coolscan IV ED priced at about $1,400.

I have outline some of the features that attracted me to this particular 35 mm film scanner below.


Nikon Coolscan IV ED 35mm film scanner

Here is an outline of some of the features that attracted me to the Nikon Coolscan IV ED 35 mm film scanner

  • The 2,900 dpi Nikon Coolscan IV ED is the entry level film scanner in Nikon's range and sells for about half the price of its faster and higher resolution Coolscan 4000 ED.
  • It would perform all of the dozen tasks that I outlined at the beginning of this article.
  • It had all of the enhancements, such as Applied Science FictionTM Digital ICE3 that I might require.
  • Reviews that I had read were very positive.
  • In my opinion it was the best value for money 35mm film scanner available at the time (mid 2001).
  • I knew that it was suitable for scanning mounted stereo slides using an easy to make adaptor (explained later).
Nikon Coolscan IV ED

Some of the technical details of the Nikon Coolscan IV ED (which for some reason Nikon also call the Coolscan LS-40) are:

  • the maximum scanning area is 25.1 x 38 mm
  • scan time for a 35 mm slide at maximum resolution is 42 seconds
  • in addition to the slide mount adaptor a film strip holder for use with the slide mount adaptor and a motorised batch film device are included.
  • included software is Nikon Scan 3 and Adobe Photoshop LE 5.0
  • the minimum PC specification is a Pentium 166 with 32 MB of RAM and 20 MB of hard disc space - higher specification recommended

A digital camera would need to be rated at 11 megapixels to achieve the resolution that can be obtained from Nikon's Coolsacn IV ED.


Digital ICE

Most of the medium to high priced film scanners have the rather amazing ability to remove surface defects such as dust, fingerprints and small scratches during the scanning process. In some cases they can also restore faded slides to their full coloured glory and virtually eliminate film grain. All of this is achieved with a combination of software and scanner hardware. Some manufacturers use their own proprietary software to achieve this while other manufacturers use the integrated software developed by Applied Science FictionTM. For example Canon use their proprietary FARE (Film Automatic Retouching and Enhancement) software. Other makers, including Nikon, Minolta and Acer, use all or some of the Applied Science FictionTM software packages such as Digital ICE, Digital ROC and Digital GEM. When all three enhancements are packaged together, as they are with the Nikon range of film scanners, they are called Digital ICE3 (ice cubed). Following are brief descriptions of what these three Applied Science FictionTM packages do:
  • Digital ICE (Image Correction & Enhancement) technology works by reading the surface defects of colour film, and recording them in a separate infrared channel. A proprietary algorithm is applied to the image, removing all the surface defects within the scan and leaving the original film intact to produce an optimal scan. Digital ICE needs to be integrated with the scanner as the scanner needs to scan the normal three RGB colour channels plus a separate infrared scan.
  • Digital ROC (Reconstruction Of Colour) technology, automatically reconstructs lost colour values in faded or aged positive or negative film resulting in scans with correct colour and exposure.
  • Digital GEM (Grain Equalisation Management) reads the grain details in the film and extracts all vital data related to image quality while effectively minimising the grain clutter without affecting sharpness. Images taken with high-speed film will appear as though they were taken with much lower speed film.
I have to say that the first time that I read about Applied Science Fiction's claims, I was a bit sceptical and thought that Science Fiction was an appropriate name. Now that I have used ICE and ROC (I have yet to try GEM) all that I can say is that "they works like magic".


Carrier Adaptations

Adaptors can probably be made to allow most film scanners to scan mounted stereo slides. I am aware that stereo slide adaptors have been made for Minolta Dimage, Tamarack Artiscan and Acer ScanWit film scanners.

However, in this section I am going to describe the very elegant and simple adaptor that was designed by stereo worker Shab Levy from Portland, Oregon, USA. This adaptor is designed for the Nikon range of film scanners.

However, it is likely that this adaptor will also work with some other film scanners as the adaptor goes into the scanner slot that is made to take a standard 50 x 50 mm (2" x 2") slide. The sketch below is by Shab Levy and much of the wording is direct from Shab's emailed advice to me.

Below is a photo of the adaptor sitting on top of my scanner and Shab Levy's sketch -

Dimensions in the sketch avove are in millimetres

The material is 3 mm thick black acrylic.

A U shaped piece of acrylic is made by cutting a stereo slide sized (101 x 41 mm) piece from a 107 x 50 mm piece of the material. A 10 x 50 mm bit is then glued at the open end of the 'U' to hold the adaptor together and to form a resting area for the part of the slide that is external to the scanner. This resting area is shown in the photo above and in Shab Levy's sketch.

The dimension shown as 41 mm on the drawing may need to be a fraction wider (say 41.5 mm) depending on the type of mounts that you use. 41.5 mm is the correct dimension for RBT mounts. Some cardboard mounts that are taped down may need a little more clearance.

The 50 mm width of the adaptor needs to be maintained as this is the width of a standard 50 x 50 mm (2" x 2") slide mount.

The adaptor and slide needs to be removed after one image (say the left) is scanned, the slide rotated and the adaptor reinserted to scan the other (right) image. When the left image is scanned it needs to be rotated 90 degrees counter clockwise before saving the file and the right image needs to be rotated 90 degrees clockwise before saving.

The photo at right shows the adaptor in use while scanning the right image of a stereo slide in an RBT mount.

In Sydney I purchased my 3 mm black acrylic and a tube of Acrifix 192 acrylic cement from Cadillac Plastics at Silverwater. They have a minimum $20 per order purchase policy, so I finished up with a lot more material than I really needed.

Ideally the adaptor should be precisely machined. A close relative of mine, who had access to a milling machine, was kind enough to make my adaptor for me.

Of course, a less durable adaptor could have been made from cardboard, however this would not be as accurate and would result in extra editing of the scanned images to line them up.


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