A film scanner is a device made for
scanning photographic film
Photographic film is a strip or sheet of transparent film base coated on one side with a gelatin photographic emulsion, emulsion containing microscopically small light-sensitive silver halide crystals. The sizes and other characteristics of th ...
directly into a computer without the use of any intermediate printmaking. It provides several benefits over using a
flatbed scanner
An image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop ''flatbed scanner'' w ...
to scan in a print of any size: the
photographer
A photographer (the Greek language, Greek φῶς (''phos''), meaning "light", and γραφή (''graphê''), meaning "drawing, writing", together meaning "drawing with light") is a person who makes photographs.
Duties and types of photographe ...
has direct control over cropping and aspect ratio from the original, unmolested image on film; and many film scanners have special
software
Software is a set of computer programs and associated documentation and data. This is in contrast to hardware, from which the system is built and which actually performs the work.
At the lowest programming level, executable code consists ...
or hardware that removes
scratches and
film grain
Film grain or granularity is the random optical texture of processed photographic film due to the presence of small particles of a metallic silver, or dye clouds, developed from silver halide that have received enough photons. While film grain ...
and improves
color
Color (American English) or colour (British English) is the visual perceptual property deriving from the spectrum of light interacting with the photoreceptor cells of the eyes. Color categories and physical specifications of color are associ ...
reproduction from film.
Film scanners can accept either strips of
35 mm or
120 film
120 is a film format for still photography introduced by Kodak for their '' Brownie No. 2'' in 1901. It was originally intended for amateur photography but was later superseded in this role by 135 film. 120 film survives to this day as the only ...
, or individual
slide
Slide or Slides may refer to:
Places
* Slide, California, former name of Fortuna, California
Arts, entertainment, and media Music Albums
* ''Slide'' (Lisa Germano album), 1998
* ''Slide'' (George Clanton album), 2018
*''Slide'', by Patrick Glees ...
s. Low-end scanners typically only take 35mm film strips, while medium- and high-end film scanners often have interchangeable film loaders. This allows the one scanning platform to be used for different sizes and packaging. For example, some allow
microscope slide
A microscope slide is a thin flat piece of glass, typically 75 by 26 mm (3 by 1 inches) and about 1 mm thick, used to hold objects for examination under a microscope. Typically the object is mounted (secured) on the slide, and then b ...
s to be loaded for scanning, while mechanised slide loaders allow many individual slides to be batch scanned unattended.
Some software used to process images scanned by film scanners allows for automatic color correction based on the film manufacturer and type. In many cases the source film may not be marked with this information in human-readable form, but might be marked at the bottom edge with a
DX film edge barcode following a standard maintained by
ANSI
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organi ...
and
I3A
The International Imaging Industry Association (I3A) was created by a merger of the Photographic and Imaging Manufacturers Association (PIMA) and the Digital Imaging Group in 2001. It was a common forum for the industrial imaging industry.
It ...
.
Dust and scratches
Dust and scratches on the film can be a big problem for scanning. Because of their reduced size (compared to prints), the scanners are capable of resolutions much higher than a regular flatbed scanner; typically at least 2000 samples per inch (spi), up to 4000 spi or more. At these resolutions dust and scratches take on gigantic proportions. Even small specks of dust, invisible to the naked eye, can obscure a cluster of several pixels. For this reason, techniques have been developed to remove their appearance from a scan, see
film restoration
Film preservation, or film restoration, describes a series of ongoing efforts among film historians, archivists, museums, cinematheques, and non-profit organizations to rescue decaying film stock and preserve the images they contain. In the wi ...
.
The simplest is the
median filter
The median filter is a non-linear digital filtering technique, often used to remove noise from an image or signal. Such noise reduction is a typical pre-processing step to improve the results of later processing (for example, edge detection on an ...
, often called ''despeckle'' in many graphic manipulation programs, e.g. in
Adobe Photoshop
Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc. for Microsoft Windows, Windows and macOS. It was originally created in 1988 by Thomas Knoll, Thomas and John Knoll. Since then, the software has become the indu ...
and the
GIMP
GIMP ( ; GNU Image Manipulation Program) is a free and open-source raster graphics editor used for image manipulation (retouching) and image editing, free-form drawing, transcoding between different image file formats, and more specialized task ...
. It works by examining a pixel in relation to the pixels surrounding it; if it is too different from the surrounding pixels then it is replaced with one set to their
median
In statistics and probability theory, the median is the value separating the higher half from the lower half of a data sample, a population, or a probability distribution. For a data set, it may be thought of as "the middle" value. The basic fe ...
value. This and other methods can be quite effective but have the disadvantage that the filter cannot know what actually is dust or noise. It will also degrade fine detail in the scan.
Infrared cleaning
Infrared cleaning works by collecting an
infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
channel from the scan at the same time as the visible colour channels (red, green, and blue). This is done by using a light source that also produces
infrared radiation
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
, and having a fourth row of sensors on the linear
CCD sensor. Photographic film is mostly transparent to infrared radiation (no matter what the visible image contains) but dust and scratches aren't, so they show up in the IR channel. This information can then be used to automatically remove the appearance of dust and scratches in the visible channels and replace them with something similar to their surroundings. A major limitation of this technique is that it can only be used on dye-based (color and chromogenic black-and-white) films; the image-forming silver particles in most black-and-white film stocks are opaque to infrared radiation.
Scanner manufacturers usually have their own name attached to this technique.
Kodak
The Eastman Kodak Company (referred to simply as Kodak ) is an American public company that produces various products related to its historic basis in analogue photography. The company is headquartered in Rochester, New York, and is incorpor ...
developed
Digital ICE {{Short description, Technique used to automatically remove dust and scratches from scanned film stock
Digital ICE or Digital Image Correction and Enhancement is a set of technologies related to producing an altered image in a variety of frequency s ...
at their Austin development centre, and is licensed by
Epson
Seiko Epson Corporation, or simply known as Epson, is a Japanese multinational electronics company and one of the world's largest manufacturers of computer printers and information- and imaging-related equipment. Headquartered in Suwa, Nagano, ...
,
Konica Minolta
is a Japanese multinational technology company headquartered in Marunouchi, Chiyoda, Tokyo, with offices in 49 countries worldwide. The company manufactures business and industrial imaging products, including copiers, laser printers, multi-fu ...
,
Microtek
Microtek International Inc. () is a Taiwan-based multinational manufacturer of digital imaging products and other consumer electronics. It produces imaging equipment for medical, biological and industrial fields. It occupies 20 percent of the glo ...
,
Minolta
was a Japanese manufacturer of cameras, camera accessories, photocopiers, fax machines, and laser printers. Minolta Co., Ltd., which is also known simply as Minolta, was founded in Osaka, Japan, in 1928 as . It made the first integrated autofocu ...
,
Nikon
(, ; ), also known just as Nikon, is a Japanese multinational corporation headquartered in Tokyo, Japan, specializing in optics and imaging products. The companies held by Nikon form the Nikon Group.
Nikon's products include cameras, camera ...
, and some others.
Canon
Canon or Canons may refer to:
Arts and entertainment
* Canon (fiction), the conceptual material accepted as official in a fictional universe by its fan base
* Literary canon, an accepted body of works considered as high culture
** Western ca ...
developed its own
FARE
A fare is the fee paid by a passenger for use of a public transport system: rail, bus, taxi, etc. In the case of air transport, the term airfare is often used. Fare structure is the system set up to determine how much is to be paid by various pa ...
(Film Automatic Retouching and Enhancement) system.
LaserSoft Imaging
LaserSoft Imaging AG is a software developer designing software such as SilverFast for scanners and large format printers. The company's headquarters are located in Kiel, Germany, north of Hamburg, and another office in Sarasota, Florida, United ...
developed the
iSRD dust and scratch removal, on which among others
Plustek is relying.
See also
*
Image scanner
An image scanner—often abbreviated to just scanner—is a device that optically scans images, printed text, handwriting or an object and converts it to a digital image. Commonly used in offices are variations of the desktop ''flatbed scanner'' ...
*
Motion picture film scanner
A motion picture film scanner is a device used in digital filmmaking to scan original film for storage as high-resolution digital intermediate files.
A film scanner scans original film stock: negative or positive print or reversal/IP. Units may s ...
External links
*
* .
* .
{{Photography
Photography equipment
Image scanners