A scanner is a device that converts prints or images on film— negatives or slides— to digital format, i.e., pixels (picture elements). A scanner consists of a fixture for holding the film or print, a light source, a CCD sensor, and associated electronics and software. Either the film or the sensor moves.
To make prints digitally from film originals you'll need to have them scanned. If you have a stock of existing film images I recommend that you purchase a scanner. Although shops can make scans, you can usually obtain the finest quality with your own scanner, and you may save money in the long run. You don't need a scanner for images made on a digital camera.
Your choice of format will be influenced by your existing equipment, your goals, your budget, and hardware availability. I now do most of my work with a digital SLR, but I have a large collection of 35mm negatives and slides dating back to the 1960s as well as a modest collection of medium format negatives. My main scanner for 35mm is the 4000 dpi Canon CanoScan FS4000US, but I still use the 2400 dpi 36 bit Hewlett-Packard PhotoSmart S20 for panoramic images. It makes decent 13 inch high (up to 33 inch long) prints. Dust can be a real pain with the HP, but the CanoScan's infrared channel dust removal is very effective. I use the Epson 3200 for medium format and larger.
We begin with a description of scanner specifications, then we discuss 35mm, medium format and large format scanners, culminating with a large Table of scanners. The use of scanners is described in a separate page, Scanning.
Film scanner specifications
Here are the key film scanner specificationss. We refer to them below.
- Resolution in pixels per inch (ppi), frequently called dots per inch (dpi), though pixels is more accurate. Ranges from 1200 dpi for large format flatbed scanners to 5400 dpi for the Minolta Scan Elite 5400 (higher for a few drum and "virtual drum" scanners, which are beyond the budgets of most consumers). This number specifies the maximum available optical resolution. You can usually select a lower resolution, which saves time and storage, if you don't plan to print large. Consider only optical resolution, not interpolated resolution (often a larger number), which you can obtain in image editing programs by resizing the image. True visual resolution in line pairs per inch (or mm) tends to be proportional to dpi for dedicated film scanners. More on the subject can be found in Understanding image sharpness part 2. (You might want to start with the explanation of MTF in part 1.) Inexpensive multipurpose flatbed scanners such as the Epson 3200 are not as sharp as dedicated film scanners— a bit disappointing because they're so versatile, but they are decent for medium format and have a sweet spot for 4x5. The apparent reason is that the lens has to cover a large area— usually 8.5 inches, unless the lens can be repositioned for the transparency unit. Excellent technique— fine lenses, fine film, and sturdy support— is required to take advantage of the higher resolution scanners.
| How many Pixels Per Inch (PPI) do you need? |
Print quality depends of the number of pixels per inch sent to the printer. The following table gives a rough guideline relating printer PPI to perceived print quality, assuming a sharp image. You can get away with lower PPI in large prints because they tend to be viewed at greater distances. These numbers are actual pixels per inch, not necessarily the dpi "resolution" of the image file, which is actually a scaling factor. Print file size and scaling are discussed in Pixels, images, and files.
| Print PPI | Perceived print quality | | 300 | Outstanding. As sharp as most printers can print; about as sharp as the eye can see at normal viewing distances. | | 200 | Excellent. Close to 300 PPI for small prints, 8½x11 (or A4) and smaller.
Outstanding quality in large prints, 11x17" (or A3) and larger, which tend to be viewed from greater distances. | | 150 | OK for large prints. Adequate, but not optimum, for small prints. | | 100 | Adequate, but not optimum, for large prints. Mediocre for small prints. | I typically aim for at least 300 PPI in 5x7 inch or smaller prints, 220 PPI in 8½x11 (A4) prints, and 180 PPI in 11x17 (A3) or larger prints. Further discussion on print resolution can be found in the page on Printers. The following table relates 35mm scanner PPI to Print PPI (Scanner PPI/magnification) for several print sizes. (A full frame 35mm image is 24x36 mm = 0.945x1.417 in.)
35mm film
scanner PPI | Print PPI print size in inches (magnification) | | 5x7 (5x) | 8½x11 (A4; 7x) | 11x17 (A3; 11x) | 13x19 (13x) | 17x24 (17x) | | 2400 | 480 | 343 | 218 | 185 | 82 | | 2900 | 580 | 414 | 263 | 223 | 171 | | 4000 | 800 | 571 | 363 | 308 | 235 | | 5400 | 1080 | 771 | 491 | 415 | 317 | Bottom line: 2400 PPI is sufficient if you don't plan to print larger than 8½x11 inches (A4; Letter size); it's very good for11x17 (A3). 2900 PPI has a slight edge at 11x17 (A3). 4000 PPI is excellent for 13x19 and even 17x24. I set my Canon FS4000US to 2000 PPI if I don't plan to print larger than Letter size. This limits file size (which can be huge at 4000 PPI) and speeds up scanning. If I plan to print A3 or larger I select maximum resolution. | |
- Dmax: the dynamic range, i.e., the maximum film density the scanner can respond to. Density is defined on a logarithmic scale as log10(fraction of light transmitted through the film). Dmax is typically between 3 (0.001 transmitted) for basic scanners and 4.8 (0.000016 transmitted) for premium scanners like the new Nikons. Scans are often noisy in areas of slides or negatives where the density is close to Dmax. You won't find much about scanner noise in manufacturer's specifications— you'll have to read about it in reviews. With certain scanners, VueScan can scan images repeatedly and use a technique called signal averaging to reduce noise. Slides are somewhat more sensitive to Dmax than negatives: Dmax = 3.6 should be sufficient for almost any slide; Dmax = 3.2 is OK for negatives and typical (but not all) slides.
- Bit depth. The number of bits per pixel, typically between 30 and 42. Scanners represent images in RGB format, three colors per pixel, so a 30-bit scanner has a 10-bit color depth (10 bits per color channel); a 42-bit scanner has a 14-bit color depth, etc. The number of levels n bits can represent is 2n: 10 bits represents 1024 levels; 14 bits represents 16384 levels. Most standard file formats store only 24 bits per pixel (8 bits per color channel; 256 levels), so they can't take advantage of the full color depth of a scan— information is lost when data is transferred out of the scanner. But you can retain all the scan information by saving it or transferring it to your image editor as a 48-bit file (16 bits per color channel; 65536 levels). When you do so, the scanner information (typically fewer than 48 bits) is padded with zeros to fill all 48 bits. I strongly recommend doing this if you want the richest prints with the finest tonality. You'll need an image editor that supports 48-bit files. Most don't; Photoshop (the full version, 6.0+, but not Elements) has limited 48-bit support. Picture Window Pro has full 48-bit support.
- TWAIN scanner interface. An industry standard interface used by Windows to transfer graphic data from scanning devices (flatbed scanners, digital cameras, etc.) directly into applications such as editing programs that can use the data. If the scanner's TWAIN interface and your image editor allow it, you can manipulate and save images in 48 bit color depth. Once you're finished manipulating the image, you may save it as a 24 bit file without loss of quality.
- Infrared (IR) channel dust removal. Some scanners acquire a separate image with an infrared light beam in order to detect the presence of dust, which responds differently to infrared than it does to visible light. Spots on the main image are filled in by interpolation. Works for all color films except Kodachrome. Does not work for B&W. This can be a very nice feature— I've spent too many hours removing dust spots from HP S20 scans with Picture Window's excellent clone tool. IR dust removal goes by the acronyms Digital ICE (Nikon and Minolta; a trademark of Applied Science Fiction) and FARE (Canon).
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Light source. This important aspect of scanners is rarely mentioned in the specs. As with enlargers (illustrated on the right), there are two essential types: collimated, i.e., beamed (shown on the left for a condenser enlarger) and diffuse (coming from all directions; shown on the right for a diffusion enlarger). All flatbed scanners have diffuse light sources; most dedicated film scanners have collimated light sources, though they differ in the degree of collimation. A "point source" would be 100% collimated.
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Collimated light sources have higher contrast when used to scan (or enlarge) Black & White film because silver grains scatter light. Since most of the light entering the film is pointed towards the enlarging lens, scattering causes a loss of light, hence an increase in contrast. This contrast increase is known as the Callier effect. With diffusion light sources, light is entering the film from all directions; as much light is scattered towards the enlarging lens as is lost; hence there is no increase in contrast. Collimated light sources tend to block highlights; diffuse light sources have a longer tonal scale— they are generally preferred for fine B&W printing. The light source has little effect of the contrast of color images because color dyes don't scatter light.
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There a persistent myth that diffusion light sources produce less sharp and less grainy images than condenser light sources. Not so! In my wet darkroom days I used a condenser enlarger for 35mm Black & White and a diffusion enlarger (a color head) for medium format and color images. The diffusion enlarger was every bit as sharp. If images from diffusion light sources seem less grainy, it is because they are less contrasty. Nevertheless, the myth may persist a while because inexpensive flatbed scanners, which have diffusion light sources, tend to be less sharp than dedicated film scanners. This is due to their optical systems: lenses on inexpensive flatbed scanners must cover an 8½ wide field; 35mm camera lenses only need to cover a 1.71 inch diagonal. The problem is not the light source.
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One indisputable advantage of diffusion light sources is that they are less sensitive to film scratches and defects— small bumps and irregularities— on the film surface (usually the backing). That is because scratches and irregularities bend light; as much light is gained from a diffuse light source as is lost. The price of this advantage is rather modest: diffusion light sources are inefficient; only a small fraction of the light reaches the enlarger lens (or the CCD). Erik de Goederen of the Netherlands markets, the Scanhancer, a device made of a special polymer resembling an ultrafine groundglass screen, that diffuses the highly collimated light source in the Minolta DiMAGE Scan Multi Pro. He claims significant advantages— lower grain and smoother tonal gradations— even with color film. Check the site for availability with newer scanners. I'd like to try one with my CanoScan FS4000US. The Minolta Scan Elite 5400 has a diffuser option, which could be more of an advantage than its high scan PPI.
If you don't own a scanner you can have images scanned to a
Kodak Photo CD: about
2200 pixels per inch (unimpressive) or 4400 pixels per inch (excellent) for the Pro Photo CD.
Dmax is
2.8-3.0 (unimpressive)— adequate for negatives but mediocre for slides. You are limited to 24 bit color.
In the discussion that follows I omit some of the technical details of individual scanners. You can find them in the scanner table, below.
Scanner types
35mm film scanners
Prices for decent (at least 2400 ppi) 35mm film scanners start around $300. Fewer models are available in 2005 than in 2003. I particularly liked the
Hewlett-Packard Photosmart S20, discontinued in 2002, because it could scan panoramic images (24
x66mm) from my Hasselblad XPan in one pass. But dust could be a pain. Compared to the inexpensive scanners (like the excellent Minolta Scan Dual IV) the better scanners have higher resolution (4000 dpi or higher), higher Dmax, and (hopefully) infrared dust removal. Images scanned at 2400-2900 dpi and
properly sharpened are about as sharp as conventional darkroom prints. 4000 ppi scanners are attractive because they can produce prints
sharper than conventional darkroom prints. I've analyzed them in gory detail in
Understanding image sharpness Part 2.
In July 2001 I purchased the 4000 dpi Canon CanoScan FS4000US 35mm/APS film scanner. Scans have 42 bit precision with Dmax = 3.4 (4.2 in 42-bit mode). Its highly effective FARE infrared channel dust removal (Canon's version of ICE) has minimal effect on image sharpness. It scans more slowly than the other 4000 dpi scanners, but its superior dust removal is likely to make the total scan process faster than the Polaroid. Reviewed by Imaging-resource (6/26/2001), Steves-Digicams (6/23/2001) and Taylor Hively. Unfortunately the hardware doesn't support panoramic scans. According to a photo.net post, there were numerous manufacturing defects (excessive noise, black dots, or "sootiness") in early samples. I heard less about defects in 2002. As of 2005 the FS4000US has been discontinued. Today I'd choose one of the Nikon or Minolta scanners listed in the scanner table, below.
| July 22, 2001 I've put up a review of the Canon CanoScan FS4000US 4000 dpi 35mm/APS film scanner. Summary: Great hardware: very sharp images and excellent color. Effective infrared dust removal. Software is mediocre, but adequate, especially if you scan to16-bit B&W or 48-bit color files. Early samples had frequent defects (mine is OK), a few of which may have resulted from easy-to-fix power line noise. I've heard that Canon's support is weak (I haven't needed it). All-in-all an excellent product. Supported by Hamrick VueScan. | |
Multipurpose flatbed scanners for 35mm, medium format, and 4x5 (inexpensive)
These scan reflected images (prints) 8.5 inches wide and come with transparency units (TPU's) of various sizes in their covers to scan film. $200 and up. They're great for historical photographs, where negatives are seldom available, but they're not as sharp as dedicated film scanners with comparable resolution, though they're improving. The reason: the lenses have to cover an 8.5 inch wide field. 35mm camera lenses only have to cover the 1.71 inch diagonal of the 24
x36 mm frame. They're adequate for 35mm enlargements up to about 8½x11 inches, excellent for most medium format uses (sharp enlargements up to 13
x19 inches), and outstanding for 4
x5 and larger (sharp at 32
x40 inches
BIG), where they have a real sweet spot. The transparency units have diffuse light sources that reduce the ill effects of dust and scratches compared with the collimated (directional) light sources in dedicated film scanners—a similar effect can be observed when comparing diffusion enlargers (cold light and color heads) to condenser enlargers.
Dedicated medium format film scanners (expensive)
These scanners have 4000+ dpi, superb image sharpenss, and excellent Dmax. The top contender (and most widely available) is the
4000 dpi
Nikon Super Coolscan 9000 ED. Dmax = 4.8 (better than 4.2 in its predecessor, the 8000 ED). Very fast.
ICE4 infrared dust removal and image enhancement. The 8000 ED was favorably reviewed by
Michael Reichmann and
Imaging-resource.com.
Miles Hecker appreciates its ability to pull detail out of shadows. The pick of the litter because it has infrared dust removal and
true 4000 dpi resolution for medium format.
Heavy metal
The Heidelberg Linoscan 1400,
Epson Expression 1680 Professional (E1680-PRO) and
Umax PowerLook 1100 flatbed scanners can handle up to 8
x10 inch film: they should be sufficient for tack sharp 48
x60 inch prints. You'll need plenty of memory and storage.
For large format photography I recommend sites by
Q.-Tuan Luong and
Paul Butzi.
Flatbed-Scanner-Review.org reviews high-end scanners.
Scanner table
With digital cameras capturing most development effort, progress in scanners has slowed, but Konica-Minolta has some intriguing new models. Steve's Digicams has a list of scanner links, which may be more up-to-date than the links here. Scanner table
listed by format— alphabetical within each format. Discontinued models in small print/gray.
|
| Scanner | Format | PPI
(DPI) | Dmax
/ bit
depth | approx.
cost
(US$) | IR dust
removal | Comments | Canon Canoscan FS4000US
(Discontinued)
| 35mm/APS | 4000 | 4.2*/42 | 600 | FARE | USB/SCSI. Scans more slowly than Nikon or Polaroid 4000 ppi scanners. See my review, which links to other reviews. *Dmax = 4.2 in 42-bit mode; 3.4 in 24-bit mode. | | HP Photosmart S20 (Discontinued) | 35mm | 2400 | ?/36 |
| no | USB. Can scan panoramic images. Discontinued in 2002. | | Konica Minolta DiMAGE Scan Dual IV | 35mm | 3200 | 4.8/48 | 240 | no | USB 2.0. APS optional. Scan Dual III was reviewed favorably by Imaging-recource.com and Steve's Digicams. Excellent buy. | | Konica Minolta Scan Elite 5400 | 35 mm | 5400 | 4.8/48 | 570 | ICE | "Grain dissolver" diffuses the light source. Exciting new product. Could be the top 35mm scanner as of mid-2003. The 5400 II (2005 model) doesn't seem to have the grain dissolver, which was one of the attractions of the 5400. The 5400 is still on KM's website, but it's getting hard to find. Photo-i review
| | Nikon Coolscan V ED (LS-50 ED) | 35mm | 4000 | 4.2/42 | 570 | ICE4 | 4000 dpi, higher speed replacement for the LS-IV ED (Oct. 2003). MSRP $600. An attractive buy | | Nikon Super Coolscan 5000 ED (LS 5000 ED) | 35mm | 4000 | 4.8/48 | 1100 | ICE4 | 16-bit depth replacement for the 4000 ED (Oct. 2003). USB 2.0. High speed scans. MSRP $1100. | | Microtek Artixscan 4000T | 35mm | 4000 | ?/36 | 460 | no* | *Software dust removal is less effective than IR. Apparent successor to Polaroid Sprintscan 4000(?) SCSI-2 interface. Polaroid reviewed by Imaging-resource. See Ian Lyons' Polaroid/SilverFast tutorial. | | Microtek Artixscan 4000tf | 35mm
| 4000 | 4.3/42 | 700
| ?
| USB and Firewire. Includes Silverfast Ai 6.0 software and additional packages. Relatively fast scans (2 min @ 4000 dpi).
| | Konica Minolta DiMAGE Scan Multi Pro | 35mm, MF | 4800 | 4.8/48 | 2850? | ICE3 | Optional 16mm and Minox holders. Dmax spec has met with some skepticism, but Imaging-resource.com was pleased. Check out the Scanhancer, which diffuses with light source, resulting in reduced grain and smoother tones. | Nikon Super Coolscan 9000 ED (LS 9000 ED)
| 35mm, MF
up to 6x9 | 4000 | 4.8/48 | 2000 | ICE4 | Replacement for the 8000 ED (Oct. 2003). IEEE 1394. High-speed scanning. MSRP $2000. Will scan 35mm panoramic images with an adaptor. | | Microtek Artixscan 120tf | 35mm, MF | 4000 | 4.2/42 | 1500
| no* | *Software dust removal. FireWire and SCSI-2. Includes Silverfast Ai 6.0 software and additional packages. Apparent successor to Polaroid Sprintscan 120(?)
| Imacon Flextight 343
Virtual Drum | 35mm, MF | 3200 | 4.3/48 | 5000
(B&H) | no | "Virtual" drum scanner. IEEE 1394. Scans up to 6x18 cm (very nice for medium format panoramic images). Drum scanners can be extremely sharp because their lenses cover tiny areas. | | Canon CanoScan 9950F | 35mm-4x5
Flatbed | 3200 | 3.3?/48 | 360
| FARE | USB 2.0. Lower resolution than dedicated film scanner; excellent for medium and large formats. I trust Epson scanners more. Scans up to 8.5x11.7 inch reflected prints. UK site. | Photo-i review | Epson Perfection 3200
(Discontinued)
| 35mm-4x9
Flatbed | 3200 | 3.4/48 | 380 | no | USB 2.0. Lower resolution than dedicated film scanner; excellent for medium and large formats. Scans up to 8.5x11.7 inch reflected prints. My review | Photo-i review. | Epson Perfection 4180
| 35mm, medium format Flatbed
| 4800
| 3.4/48
| 185
| no
| Good budget choice for medium format film. Resolution may be better than the 3200. USB 2.0. | Epson Perfection 4990
| 35mm-8x10 Flatbed
| 4800
| 4.0/48
| 450
| ICE
| Outstanding choice for medium and large format film. Resolution apparently considerably better than the 3200. USB 2.0 and Firewire. Successor to the 4870, reviewed by George Nyman. Photo-i review
| Microtek ScanMaker i700
| 35mm-4x9 Flatbed
| 4800
| ?/48
| 330
| ICE
| Scans 8.5x14" (legal-size) reflective documents. USB 2.0, Firewire. Includes Silverfast SE 6.0. Why don't they specify Dmax?
| | Microtek ScanMaker i900 | 35mm-8x10 Flatbed | 3200
| 4.2/48 | 540
| ICE
| Scans 8.5x14" (legal-size) reflective documents. USB 2.0, Firewire. | | Epson 1680 (E1680-PRO) | 35mm-8x10
Flatbed | 1600 | 3.6/48 | 1050 | no | Comes in several versions. Includes Silverfast Ai5 software. See photo.net post. Difficult to justify now that 4990 is available.
| | Heidelberg Linoscan 1400 | 35mm-8.5x11.7
Flatbed | 1200 x2400 | 3.4/42 | 1395 | no | SCSI. 1450 has Firewire interface. | | Umax PowerLook 1100 | 35mm-8.5x11.7
Flatbed | 1200 x2400 | 3.4/42 | 870 | no | FireWire/IEEE-1394. Watch for new PowerLook 270 with ICE. | Imacon Flextight 848
Virtual Drum | 35mm-5x7 | 8000 | 4.8/48 | 18,000 | no | The gold standard. Lower resolution for larger formats. "Virtual" drum scanner uses an actively-cooled CCD. True drum scanners use photomultiplier tubes. Fast (100 MB/min) | Imacon Flextight 646
Virtual Drum | 35mm-5x7 | 6300 | 4.6/48 | 14,000
(B&H) | no | Slower than the 848 (40 MB/min.). CCD not actively cooled. | | Imacon Flextight Precision III | 35mm-5x7 | 6300 | 4.3/42 | 10000
(B&H) | no | Virtual drum. Slower than the 646 (20 MB/min.) | |
| If you are buying a scanner, you can help support this website by purchasing it through Adorama, which offers competitive prices and excellent service. Just click on the price, above. |
| Notes | Flatbed scanners scan reflected documents as well as film. All others are film-only ("dedicated" film scanners). Flatbed scanners tend to be less sharp than dedicated film scanners because their lenses have to cover larger fields— typically 8.5 inches wide. But recent models have improved significantly.
| | MF (medium format) scanners scan up to 6x9 cm. | | Most scanners with bit depth greater than 24 (8 bits per color channel) can transfer 48 bit files (16 bits per color channel) to the image editor via the TWAIN interface. | | Where two dpi numbers are specified, e.g., 1200x2400, the lower number is the more significant. The higher number is merely the stepper motor pitch. | |
. The bottom line is that scanners are excellent and prices are dropping, though change has slowed down now that manufacturers are concentrating their efforts on digital cameras. You can make satisfying 13
x19 inch prints from 35mm negatives scanned at 2400 dpi (better at 3200+ dpi), and you can make amazingly sharp prints— better than darkroom prints— with a 4000 dpi scanner.
All the scanners I've mentioned provide excellent results when used properly. It's more important to learn to use your scanner well than to purchase the latest, greatest model. (This is true of most other equipment, as well.) I discuss the use of scanners— how to get the most out of them— in Making fine prints Part 2: Scanning.
Film scanner links
- Imaging Resource scanner reviews The best overall source of scanner reviews with excellent tutorials. Kept up-to-date.
- Ken Rockwell's Scanner Recommendations — a nice list, with opinions.
- Popular Photography has some scanner reviews, well worth reading. This page also includes links to film, printer and software reviews. Since it's hard to tell if they'll keep it up, here are links to the Canon FS4000US, 7 film scanners and 10 flatbed scanners.
- Tony Sleep's Film Scanner Reviews More than you wanted to know, but may not be up-to-date. His Filmscanners List archive can be accessed by Thread, Subject or Search. It gets a huge number of posts. Well worth looking at, but don't sign up for the e-mail list unless you want an average of 40 e-mails a day.
- Steve Hoffman's Nature and Scenic Photography Good information on HP and Nikon scanners.
- VueScan Highly regarded inexpensive scanner software which works on most film scanners. Updated frequently. I use it for panoramic scans with the HP S20. This photo.net post has some tips and a comparison with SilverFast.
- SilverFast Scanning software. More professional, flexible and expensive than VueScan.
- Scanning tips by Wayne Fulton. Covers flatbed and film scanners.
- A Primer on Image Histograms and Curves— How to scan by Dane Kosaka.
- Photo.net's forum on scanning (a geek's delight with over 400 threads) and scanner reviews.
- Filmscanner.info Extremely informative site, in Deutsch. Worth translating.
Scanning film
Images and text copyright © 2000-2009 by Norman Koren.
Norman Koren lives in Boulder, Colorado, founded Imatest LLC in 2004, previously worked on magnetic recording technology. He has been involved with photography since 1964. |  |
The human eye is sensitive to electromagnetic radiation with wavelengths between about 380 and 700 nanometers. This radiation is known as 
