Preservation Digitisation Standards

For the digitisation of physical RNA records

Preservation, Collection Management

November 2018

Executive summary

The Preservation Digitisation Standards set out the required standards for digitisation of physical records of archival value (RNA) and are designed for internal, outsourced and agency digitisation of RNA records. These standards ensure that preservation digitisation activities produce a digital copy which is an effective long-term surrogate for paper and analogue originals. They also enable the creation of derivative files to meet access requirements and minimise the physical wear and tear caused by handling fragile collection items.

The standards have been developed in line with the standards of national and international GLAM (Gallery, Library, Archive and Museum) institutions. They set out the technical requirements for digitisation outputs produced under the National Archives' National Digitisation Plan, which supports the National Digitisation and Preservation Strategies.

The preservation format for all non-audiovisual records is TIFF, with JPEG and PDF file formats used for access derivatives. TIFF is designed to capture all the attributes of typed or written text accurately as high quality images in a stable format and is widely supported for the digitisation of archival records. The preservation standard for audiovisual formats varies for audio, video and motion picture film, but is compliant with industry standards.

Background

The National Archives of Australia has a key responsibility to preserve and make publicly available Australian Government records that reflect our history and identity.

The National Archives' collection traces events and decisions that have shaped the nation and the lives of Australians. It includes a wide range of formats including files and documents, volumes, registers, index cards, maps, plans, charts, photographs, films, and video and audio recordings in a variety of analogue and, increasingly, many diverse digital formats.

The unique and diverse analogue collection contains formats that are physically deteriorating through use, inherently unstable, or at risk of becoming inaccessible due to the technological obsolescence of the appropriate playback equipment.

The Preservation Digitisation program ensures that Australians have continued online access to a national archival collection so they may better understand their heritage and democracy.

Purpose

The National Archives has a key responsibility to preserve and make publicly available the archival resources of the Commonwealth.

Preservation digitisation reduces the physical wear and tear on fragile records and is an effective tool to preserve records at risk of being lost if they are held on unstable media or subject to technological obsolescence. The creation of derivatives during the digitisation process assists the National Archives to make its collection accessible and available online to a wide and varied range of current and future users.

The Preservation Digitisation Standards set out the technical requirements for digitisation outputs produced under the National Digitisation Plan, which supports the National Digitisation and National Preservation Strategies.

The Preservation Digitisation Standards should be reviewed on an annual basis to ensure that they are in line with the standards of other national and international GLAM institutions. Digital technology is continually evolving and, to take advantage of increased capability which may enable the National Archives to digitise to a higher standard, the standards should also be reviewed, when technology emerges, industry standards changes, or when new digitisation equipment is purchased.

The Preservation Digitisation Standards are guided by the nature of our collection and the National Archives' vision to secure, preserve and make accessible this priceless information for the benefit of current and future generations.

The technical standards are informed by the following guiding principles to ensure that preservation digitisation activities produce a digital copy which is an effective long-term surrogate for paper and analogue originals.

The preservation digital surrogate will:

  • capture a complete and accurate archival record of analogue collection items
  • be preserved and accessible for the foreseeable future
  • enable the re-use of the digitised content to meet known, unknown and likely current and future access requirements
  • enable the creation of derivative files to meet access requirements and minimise the physical wear and tear caused by handling fragile collection items.

To support these standards, supplementary guidelines and procedures will provide additional capture, handling and quality assurance requirements for each format.

File formats

Archival Master File Format (digital surrogate)

Preservation digitisation is not geared for any specific output and should be done in a use-neutral manner using a format that preserves the essential characteristics of the original records and is uncompressed or has lossless compression. The master image files produced should be usable for a wide variety of applications and outputs.

The choice of Archival Master file format for each analogue format for these standards has been based on an environmental scan of national and international cultural institutions and organisations.

TIFF is the preservation file format for all non-audiovisual records, with JPEG and PDF file formats utilised for access derivatives. The preservation standard for audiovisual (AV) formats varies for audio, video and motion picture film, but is compliant with industry standards.

Access File Format

The choice of access formats is dependent on the intended business use of the digital file. These derivative files are generally created as an additional product when digitising for preservation.

For paper formats the standard provides specifications for the creation of three access copies in line with current practices for providing access via RecordSearch: large JPEG (viewing copy), small JPEG (thumbnail) and PDF (complete item).

For photographic, aerial and microform formats, only a large JPEG (viewing copy) and small JPEG (thumbnail) are derived from the Archival Master to provide access via RecordSearch.

Access copies for audiovisual formats are created on an as needs basis, as RecordSearch is not currently able to make these formats available online.

Commencement

These standards apply to all digitisation commenced from:

  • 1 January 2019: all internal proactive digitisation projects, including where outsourced
  • 1 July 2019:
    • all digitisation by Australian Government agencies of material that is of archival value (RNA), including under the Agency Digitisation Service
    • on-demand digitisation undertaken by the National  Archives in response to client (agency, public) demand.

Preservation Digitisation Standards

1. Paper documents (unbound) under A3

Archival documents in this category can include single folios, files and index cards. A file is a collection of documents held together in a folder. The documents within the file are often fastened together using staples, paperclips or pins. The types of documents found on a file can include:

  • documents and artworks on paper
  • photocopies and laser prints
  • thermal papers
  • maps and plans
  • photographs.

Documents can vary in contrast and this may affect the requirements for producing a clear quality digital image. Documents with a well-defined print type with a high level of contrast between the ink and paper and with no discolouration or staining of the paper substrate can be scanned in 8-bit colour. Older documents, with handwritten annotations, poor legibility and low contrast between the text and paper, or where the substrate is faded or stained, should be scanned at a higher bit rate of 16-bit colour.

Files containing multiple documents will be digitised to single page TIFF files, not to a multi-page TIFF.

Any photographic negatives and transparencies attached to, or found within, files and documents should be digitised using the photographic digitisation standards in this document.

1.1 Paper documents under A3

Archival Master – Capture ratio 100% with no manipulation


Derivative
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Derivative 3
PDF
Format

Paper documents under A3

Purpose

Preservation

Access

Access

Access

File type

TIFF 6.0

JPEG

JPEG

PDF/A

Compression

uncompressed

JPEG compression
Photoshop level
10-12

JPEG compression
Photoshop level
10-12

Minimum compression

Resolution

400 ppi

300 ppi

1000 pixels longest edge

300 ppi

Bit depth

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

AdobeRGB

sRGB

sRGB

sRGB

2. Large format paper documents (unbound) over A3

(Including maps, plans and large format records)
Records larger than A3 cannot fit easily onto a standard flatbed scanner.  This may include document types such as maps, charts, architectural and engineering drawings, posters or other large handwritten, typed or printed documents.

Many of these formats contain fine details. Where there is very fine detail, a higher scanning resolution of 600ppi may be required to produce a more legible image.

Due to their larger dimensions, the scanning of oversize images can produce very large file sizes.

Do not leave oversized records in scanning equipment unattended or unsupported as this can lead to damage.

Oversized materials, including books that have foldouts, must be scanned using equipment that features a scanning bed that is as large, or larger than the item to be scanned.

Do not place glass or other transparent material directly on top of fragile artwork, documents, manuscripts, prints, photographs, with or without mounts, as this can cause media to crack or to detach from the item. Use spacers on fragile items to prevent compression between an item and a glass plate.

2.1 Documents over A3 (including maps, plans and large format records)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Derivative 3
PDF
Format type

Documents over A3 (including maps, plans and large format records)

Purpose

Preservation

Access

Access

Access

File type

TIFF 6.0

JPEG

JPEG

PDF/A

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Minimum compression

Resolution

400 ppi

3000 pixels longest edge

150 pixels longest edge

300 ppi

Bit depth

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

AdobeRGB

sRGB

sRGB

sRGB

2.2 Rare or significant documents, artworks, posters or large format records with a high level of detail

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Derivative 3
PDF
Format type

Rare or significant documents, artworks, posters or large format records with a high level of detail

Purpose

Preservation

Access

Access

Access

File type

TIFF 6.0

JPEG

JPEG

PDF/A

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Minimum compression

Resolution

600 ppi

3000 pixels longest edge

150 pixels longest edge

300 ppi

Bit depth

16 bit colour
(48 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

AdobeRGB

sRGB

sRGB

sRGB

3. Bound volumes

The term volume refers to an item in the form of a bound book. Volumes may be bound in a variety of styles and materials to protect the pages inside. Types of binding styles found in archival collections may include:

  • case bindings where the cover is made separately and wrapped around the text block. This can include fine, decorative or limited edition volumes, logbooks and diaries.
  • large leather or suede bound 19th century ledgers and registers
  • simple do-it-yourself bindings such as comb or spiral bindings used for business and government reports, diaries and one-off documents
  • loose-leaf binders and folders that allow individual leaves to be easily added or exchanged
  • post bindings, which use a number of metal posts or screws to hold the binding and the text block together.

Handling issues

Flatbed scanners are not recommended for bound volumes. Pressure should not be applied to books in order to flatten them for image capture as this can break the spine or loosen or break off brittle pages in a book.

Books with weak joints or restricted openings should be placed in a book cradle (blocks or rolls of polyethylene foam) during image capture.

Scanning equipment must be adjustable to the height of the collection item to accommodate books that need cradle support.

3.1 Bound volumes

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Derivative 3
PDF
Format type

Bound Volumes

Purpose

Preservation

Access

Access

Access

File type

TIFF 6.0

JPEG

JPEG

PDF/A

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Minimum compression

Resolution

400 ppi

300 ppi

1000 pixels longest edge

300 ppi

Bit depth

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

AdobeRGB

sRGB

sRGB

sRGB

4. Photographic prints and negatives

Photographic records contain an image formed in a binder layer on paper, resin coated paper, cellulose acetate, cellulose nitrate or polyester base. Black-and-white images are formed by metallic silver particles and colour images by dye layers. In the National Archives' collection the binder layer most commonly consists of a gelatine emulsion; early processes can also be albumen or collodion. Photographic print images are on a paper (occasionally plastic) base, and negatives or positive transparencies have a clear plastic or sometimes glass base.

Nitrate and acetate-based negatives are prone to deterioration of both the image and base layer. This deterioration can be slowed significantly by storing negatives at low temperature and relative humidity. The only other practical way to preserve the images and make them accessible is to digitise them.

For the purposes of preservation digitisation the photographic collection can be grouped in the categories below:

Prints:

  • Colour and black-and-white photographic prints – smaller than A6 (10 x 15cm)
  • Colour and black-and-white photographic prints – A6 to A4 (10 x 15cm to 21x30cm)
  • Colour and black-and-white photographic prints – over  A4 (over 21x30cm)

Transparent materials such as glass can be used to hold the edge of an image flat during digitisation, but care must be taken that the original is not harmed while under pressure. Tightly curled materials must not be forced to lay flat. Care must be taken to assure that flattening a photograph will not result in emulsion cracking, or the base material being damaged.

Negatives and transparencies (including glass plate negatives and positives):

  • Colour and black-and-white negatives and transparencies – up to 35mm
  • Colour and black-and-white negatives and transparencies  – over 35mm to 4"X5"
  • Colour and black-and-white negatives and transparencies  – over 4"X5"

If using a high-end digital camera, the use of a 5000K light box and calibrated viewing environment is critical when scanning negatives and transparencies.

The initial raw scan of a negative captures all of the information required for a preservation digital surrogate. To make the image accessible, the raw scan is inverted to create a positive image. We retain both the raw file and the inverted master file as archival masters.

Handling issues

Glass plate negatives may not be put under pressure. They are not always perfectly flat or may have hairline cracks, resulting in breakage when pressure is applied.

Photographic prints (colour and B&W)

4.1 Colour photographic prints – smaller than A6 (10 x 15cm)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Colour Photographic Prints - Smaller than A6 (10 x 15cm)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

2700 ppi

1290 pixels longest edge

200 pixels longest edge

Bit depth

16 bit colour
(48 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

Pro Photo RGB

sRGB

sRGB

4.2 Black-and-white photographic prints – smaller than A6 (10 x 15cm)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

B&W Photographic Prints - Smaller than A6 (10 x 15cm)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

2700 ppi

1290 pixels longest edge

200 pixels longest edge

Bit depth

16 bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

4.3 Colour photographic prints – A6 to A4 (10 x 15cm to 21x30cm)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Colour Photographic Prints - A6 to A4 (10 x 15cm to 21x30cm)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG Level 10

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

900 ppi

1290 pixels longest edge

200 pixels longest edge

Bit depth

16 bit colour
(48 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

Pro Photo RGB

sRGB

sRGB

 

4.4 Black-and-white photographic prints – A6 to A4 (10 x 15cm to 21x30cm)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

B&W Photographic Prints - A6 to A4 (10 x 15cm to 21x30cm)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG Level 10

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

900 ppi

1290 pixels longest edge

200 pixels longest edge

Bit depth

16bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

4.5 Colour photographic prints – over A4 (over 21x30cm)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Colour Photographic Prints – Over A4 (over 21x30cm)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG Level 10

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

600 ppi

1290 pixels longest edge

200 pixels longest edge

Bit depth

16 bit colour
(48 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

Pro Photo RGB

sRGB

sRGB

4.6 Black-and-white photographic prints – over A4 (over 21x30cm)

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

B&W Photographic Prints - Over A4 (over 21x30cm)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG Level 10

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

600 ppi

1290 pixels longest edge

200 pixels longest edge

Bit depth

16 bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

Photographic Negatives and Transparencies (Colour and BLACK AND WHITE)

4.7 Colour negatives and transparencies – up to 4"X5"

Archival Master – Capture ratio 100% with no manipulation

DerivativeRaw
Digital surrogate
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Colour negatives and transparencies – up to 35mm

Purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0 or DNG

TIFF 6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000 ppi

5000 ppi

1290 pixels longest edge

150 pixels longest edge

Bit depth

16 bit colour
(48 bit)

16 bit colour
(48 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

Pro Photo RGB

Pro Photo RGB

sRGB

sRGB

4.8 Black-and-white negatives and transparencies – up to 4"X5"

Archival Master – Capture ratio 100% with no manipulation

DerivativeRaw
Digital surrogate
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

B&W negatives and transparencies – up to 35mm

Purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0 or DNG

TIFF6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000 ppi

5000 ppi

1290 pixels longest edge

150 pixels longest edge

Bit depth

16bit

16bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

4.9 Colour negatives and transparencies – over 4"X5"

Archival Master  – Capture ratio 100% with no manipulation

DerivativeRaw
Digital surrogate
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Colour negatives and transparencies – over 4"X5"

Purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0 or DNG

TIFF 6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

4000 ppi

4000 ppi

1290 pixels longest edge

150 pixels longest edge

Bit depth

16 bit colour
(48 bit)

16 bit colour
(48 bit)

8 bit colour
(24 bit)

8 bit colour
(24 bit)

Colour space

Pro Photo RGB

Pro Photo RGB

sRGB

sRGB

4.10 Black-and-white negatives and transparencies – over 4"X5"

Archival Master – Capture ratio 100% with no manipulation

Derivative

Raw
Digital surrogate

Archival Master
Digital surrogate

Derivative 1
Large

Derivative 2
Small

Format type

B&W negatives and transparencies – over 4"X5"

Purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0 or DNG

TIFF 6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

4000 ppi

4000 ppi

1290 pixels longest edge

150 pixels longest edge

Bit depth

16bit

16bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

5. Aerial film and photographs

Aerial film and photographs form a sub-category of the National Archives' photographic collection. An aerial photograph is a photograph of the ground taken from an elevated position, usually from the air or sky. Aerial photographs provide a straightforward depiction of the physical and cultural landscape of an area at a given point in time. Aerial photographs in particular have fine detail, often require a high degree of enlargement, and may require a higher degree of precision regarding the dimensional accuracy when digitised.

The use of an approved 'film winder' is essential for digitisation activity on wound roll aerial film.

A suitable very high resolution digital camera is used in conjunction with a flashbox light box and a film winder.

For the purposes of preservation digitisation the aerial photographic collection can be grouped in the below categories:

  • aerial prints – up to 8"x10"
  • aerial prints – over 8"x10"
  • aerial film – 70mm, 127mm roll film and medium format roll film
  • aerial film – 4 x 5 and up to and including 5 x 7 sheet film
  • aerial film – larger than 127mm roll film/ larger than 5 x 7 sheet film
  • glass plates.

5.1 Aerial prints – up to 8"x10"

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Aerial Prints - Smaller 4"x5"

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000ppi

1500 pixels longest edge

300 pixels longest edge

Bit depth

16 bit
(48 bit) colour

8 bit
(24 bit)  colour

8 bit
(24 bit) colour

Colour space

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

5.2 Aerial prints – over 8"x10"

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Aerial Prints – over 8"x10"

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

4000ppi

1500 pixels longest edge

300 pixels longest edge

Bit depth

16 bit
(48 bit) colour

8 bit
(24 bit)  colour

8 bit
(24 bit) colour

Colour space

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

5.3 Aerial film – 70mm, 127mm roll film and medium format roll film

Archival Master – Capture ratio 100% with no manipulation

DerivativeRaw
Digital surrogate
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Aerial film – 70mm and medium format roll film

Purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0

TIFF 6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000 ppi

5000 ppi

1500 pixels longest edge

150 pixels longest edge

Bit depth

16 bit
(48 bit) colour

16 bit
(48 bit) colour

8 bit
(24 bit)  colour

8 bit
(24 bit) colour

Colour space

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

5.4 Aerial film – 4 x 5 and up to and including 5 x 7 sheet film

Archival Master – Capture ratio 100% with no manipulation

DerivativeRaw
Digital surrogate
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Aerial film - 127mm roll film/ 4 x 5 and up to and including 5 x 7 sheet film"

Purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0

TIFF 6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000 ppi

5000 ppi

1500 pixels longest edge

150 pixels longest edge

Bit depth

16 bit
(48 bit) colour

16 bit
(48 bit) colour

8 bit
(24 bit)  colour

8 bit
(24 bit) colour

Colour space

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

5.5 Aerial film – larger than 127mm roll film/ larger than 5 x 7 sheet film

Archival Master – Capture ratio 100% with no manipulation

DerivativeRaw
Digital surrogate
Archival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Aerial film - Larger than 127mm roll film/ larger than 5 x 7 sheet film

File name and purpose

Preservation

Preservation

Access

Access

File type

TIFF 6.0

TIFF 6.0

JPEG

JPEG

Manipulation

None
Raw negative file

Inverted to positive with some adjustments

Derived from Archival Master

Derived from Archival Master

Compression

uncompressed

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000 ppi

5000 ppi

1500 pixels longest edge

150 pixels longest edge

Bit depth

16 bit
(48 bit) colour

16 bit
(48 bit) colour

8 bit
(24 bit)  colour

8 bit
(24 bit) colour

Colour space

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

Grey Gamma 2.2 (B&W)
Pro Photo RGB (colour)

6. X-Ray film (Radiographs)

X-ray film, like black-and-white photographic film, consists of a silver image formed in a gelatine emulsion on a transparent cellulose nitrate or acetate base. X-rays have the same deterioration characteristics, preservation and storage issues as other film-based photographic materials.

Few scanners are capable of imaging radiographs properly due to their very wide density range and large size. There are specialised film scanners built for this application.

6.1 X-ray film

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

X-Ray Film (Radiographs)

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG

Compression

uncompressed

JPEG compression
Photoshop Level
10-12

JPEG compression
Photoshop Level
10-12

Resolution

5000 ppi

1000 pixels longest edge

150 pixels longest edge

Bit depth

16bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

7. Microforms

Microform is the term used to cover a range of photographic media employed to copy documents. It includes microfilm, microfiche and aperture cards. A master microfilm is usually black-and-white silver halide film made from original records. It is used to produce reference copies using less expensive, more robust but less archival dye-based processes on Diazo Film, or a Vesicular Film which produces a positive image (if copied from a negative film) with 10–20 years' archival life. Microfilm readers are then used to view or digitise the reference copies.

For the purposes of preservation digitisation the microfilm collection can be grouped in the below categories:

  • 16mm and 35mm microfilm
  • aperture card – mainly produced with a single frame of 35mm film mounted within the open aperture
  • microfiche – come in a variety of formats, standard size is 105 mm by 148 mm.

Due to photographic limitations of microfilm and the variable quality of older microfilm, it may not be possible to produce what would normally be considered reproduction quality image files. The choice of scanning approach may vary from the recommendations for textual records, and may be more focused on creating digital images with reasonable legibility.

Digital reproductions should be made from a preservation copy of microfilm, if available.

Crop to include the visible edge of pages.

The reduction scale of the microfilm may be unknown, given that there is no way to confirm the original imaging parameters.

7.1 Microfilm, microfiche, aperture card

Archival Master – Capture ratio 100% with no manipulation

DerivativeArchival Master
Digital surrogate
Derivative 1
Large
Derivative 2
Small
Format type

Microfilm, Microfiche, aperture card

Purpose

Preservation

Access

Access

File type

TIFF 6.0

JPEG

JPEG

Compression

none

JPEG compression
Photoshop level
10-12

JPEG compression
Photoshop level
10-12

Resolution

4000 ppi

700 pixels longest edge

150 pixels longest edge

Bit depth

8bit

8 bit

8 bit

Colour space

Grey Gamma 2.2

Grey Gamma 2.2

Grey Gamma 2.2

8. Audio formats

The specifications apply to all physical audio formats including:

  • compact cassette
  • micro cassette
  • mini cassette
  • ¼" open reel tape
  • gramophone discs
  • digital audio tape (DAT)
  • CD audio
  • 16 mm, 17.5 mm and 35 mm magnetic or optical motion picture film sound.

For audio digitisation the National Archives follows the standards, practices and strategies detailed in the publication: International Association of Sound and Audiovisual Archives (IASA) – Guidelines on the Production and Preservation of Digital Audio Objects (IASA TC-04 Second Edition, 2009). https://www.iasa-web.org/tc04/audio-preservation

The number of audio channels should always be based on the format of the original item, rather than the recorded signal.  For example, a single microphone recorded on a stereo cassette recorder will have a mono signal but the format is stereo so playback and the copy should be stereo.

8.1 Gramophone disc, ¼ inch tape 7.5ips or higher, music on compact cassette and magnetic or optical motion picture film sound

DerivativeArchival Master
Digital surrogate
Derivative 1
small
Format type

Gramophone disc, ¼ inch tape 7.5ips or higher, music on compact cassette magnetic or optical motion picture film sound

Purpose

Preservation

Access

File type

BWF

mp3 (MPEG-2 Layer III)

Encoding

LPCM (Linear Pulse Code Modulation)

Sampling frequency

96 kHz

48kHz

Bit Depth/rate

24-bit

192kbit/s CBR

Audio channel

Same as original

Same as original

8.2 ¼ inch tape 3.75ips or less, speech on compact cassette, micro cassette

DerivativeArchival Master
Digital surrogate
Derivative 1
small
Format type

¼ inch tape 3.75ips or less, speech on compact cassette, micro cassette

Purpose

Preservation

Access

File type

BWF

mp3 (MPEG-2 Layer III)

Encoding

LPCM (Linear Pulse Code Modulation)

Sampling frequency

48 kHz

48kHz

Bit depth/rate

24-bit

192kbit/s CBR

Audio channel

Same as original

Same as original

8.3 Digital formats (for example DAT)

DerivativeArchival Master
Digital surrogate
Derivative 1
small
Format type

Digital formats (e.g. DAT)

Purpose

Preservation

Access

File type

BWF

mp3 (MPEG-2 Layer III)

Encoding

LPCM (Linear Pulse Code Modulation)

Sampling frequency

Same as original

Same as original

Bit depth

Same as original

192kbit/s CBR

Audio channel

Same as original

Same as original

9. Video formats

The specifications apply to all physical video formats containing video, including:

  • One Inch, Two Inch
  • VHS
  • Betamax, Betacam, Betacam SP, Betacam SX, Betacam HD, Digital Betacam
  • Video 8
  • EIAJ Open Reel, EIAJ Cartridge
  • Hi 8
  • Umatic
  • D2
  • Mini DV
  • DV Cam, XD Cam, HD Cam
  • Laserdisc.

For video digitisation the operator must confirm that the aspect ratio is the same as the original, that there is accurate sync between audio and video, and that the preservation file copy displays the same interlacing as the original source tape.

The National Archives is currently reviewing the International Association of Sound and Audiovisual Archives (IASA) – Guidelines for the Preservation of Video Recordings (TC 06) which had its initial release in 2018.

9.1 High definition video

DerivativeArchival Master
Digital surrogate
Derivative 1
small
Format type

High definition video

Purpose

Preservation

Access

File type

MXF OP-1a

MPEG 4 Base Media / Version 2

Video codec

MJPEG2000
lossless compression encoding

AVC High@L4.0

bit depth/rate

10 bit - ~100Mb/s VBR

8 bit - 5Mb/s CBR

Frame size

Same as original

Same as original

Frame rate

Same as original

Same as original

Colour space

Same as original

YUV

Chroma subsampling

Same as original

4:2:0

Audio stream

BWF
48 kHz, 16 bit PCM encoding

48 kHz, 8 bit AAC,125kbps

9.2 Standard definition video

DerivativeArchival Master
Digital surrogate
Derivative 1
small
Format type

Standard definition video

Purpose

Preservation

Access

File type

MXF OP-1a

MPEG 4 Base Media / Version 2

Video codec

MJPEG2000
lossless compression encoding

AVC High@L3.1

bit depth/rate

10 bit - ~50Mb/s VBR

8 bit - 1.5Mb/s CBR

Frame size

PAL – 720 x 576
NTSC - 720 x 486

PAL – 720 x 576
NTSC - 720 x 486

Frame rate

PAL – 25fps
NTSC - 29.97fps

PAL – 25fps
NTSC - 29.97fps

Colour space

YUV

YUV

Chroma subsampling

4:2:2

4:2:0

Audio stream

BWF
48 kHz, 16 bit PCM encoding

48 kHz, 8 bit AAC,125kbps

10. Motion picture film

Motion picture film held at the National  Archives is predominantly on 8mm, 16mm and 35mm gauges. Motion picture film consists of a gelatine emulsion on a plastic support base of cellulose nitrate, cellulose acetate or polyester. The image is formed in the emulsion layer from colour dyes or silver halide particles.

Motion picture film is prone to deterioration due to degradation of the inherently unstable film base. Colour film is also prone to dye fade. Deterioration can be slowed by storing film at low temperature and relative humidity. The National Archives also preserves film through digitisation to industry standard digital file types.

The specifications in this document apply to all physical motion picture film formats including:

  • 8mm,  16mm and 35mm  positive and negative film
  • Super 8mm,  Super 16mm and Super 35mm film.

Motion picture films intended for theatre projection will have been recorded at 24 frames per second, whereas those intended for television will be 25 frames per second. It is important that the film is scanned at the correct frame rate and that magnetic or optical film sound is preserved at its original recorded speed.

10.1 Super 35mm and 35mm positive and negative film

DerivativeArchival Digital MasterDerivative 1
Format type

35mm and Super 35mm positive and negative film

Purpose

Preservation

Access

File type

DPX ( SMPTE-268 2003) uncompressed

MPEG 4 Base Media / Version 2

Video codec

 

AVC High@L4.0

Resolution

4096 x 3072 (4K ) or
5120 x 3840 (5k)

1920x1080 (HD)

Bit depth/rate

10Bit

8 bit - 5Mbps CBR

Chroma subsampling

4:4:4

4:2:0

Colour space

RGB

YUV

Audio stream

BWF 48 kHz, 24 bit PCM encoding

48 kHz, 8 bit AAC,125kbps

Frame rate

24fps

24fps

10.2 16mm positive film 24fps

DerivativeArchival Digital MasterDerivative 1
Format type

16mm positive film

Purpose

Preservation

Access

File type

DPX ( SMPTE-268 2003) uncompressed

MPEG 4 Base Media / Version 2

Video codec

 

AVC High@L4.0

Resolution

2048x1556 (2K )

1920x1080 (HD)

Bit depth/rate

10Bit

8 bit - 5Mbps CBR

Chroma subsampling

4:4:4

4:2:0

Colour space

RGB

YUV

Audio stream

BWF 48 kHz, 24 bit  PCM encoding

48 kHz, 8 bit AAC,125kbps

Frame rate

24fps

24fps

10.3 16mm positive film 25fps (kine, telerecordings)

DerivativeArchival Digital MasterDerivative 1
Format type

16mm positive film

Purpose

Preservation

Access

File type

AVI

MPEG 4 Base Media / Version 2

Video codec

Uncompressed

AVC High@L4.0

Resolution

1920x1080 (HD)

1920x1080 (HD)

Bit depth/rate

10 bit

8 bit - 5Mbps CBR

Chroma subsampling

4:2:2

4:2:0

Colour space

YUV

YUV

Audio stream

BWF 48 kHz, 16 bit PCM encoding

48 kHz, 8 bit AAC,125kbps

Frame rate

25fps

25ps

10.4 16mm negative and Super 16mm negative film

DerivativeArchival Digital MasterDerivative 1
Format type

16mm negative and Super 16mm negative film

Purpose

Preservation

Access

File type

DPX ( SMPTE-268 2003) uncompressed

MPEG 4 Base Media / Version 2

Video codec

 

AVC High@L4.0

Resolution

2048x1556 (2K )

1920x1080 (HD)

Bit depth/rate

10 Bit

8 bit - 5Mbps CBR

Chroma subsampling

4:4:4

4:2:0

Colour space

RGB

YUV

Audio stream

BWF 48 kHz, 24 bit  PCM encoding

48 kHz, 8 bit AAC,125kbps

Frame rate

As per original 24fps or 25ps

As per original 24fps or 25ps

10.5 Super 8mm and Standard 8mm positive and negative film

DerivativeArchival Digital MasterDerivative 1
Format type

Super 8mm and Standard 8mm positive and negative film

Purpose

Preservation

Access

File type

DPX ( SMPTE-268 2003) uncompressed

MPEG 4 Base Media / Version 2

Video codec

 

AVC High@L4.0

Resolution

2048x1556 (2K )

1920x1080 (HD)

Bit depth/rate

10 Bit

8 bit - 5Mbps CBR

Chroma subsampling

4:4:4

4:2:0

Colour space

RGB

YUV

Audio stream

 

 

Frame rate

As per original

As per original

Glossary

Access File Format

A derivative file created at the same time or from the Archival Master file. The format is dependent on intended use. As it is not an archival format it can be compressed.

Archival Master File

The Archival Master preserves the essential characteristics of the original records and is uncompressed or has lossless compression.

Audio channel

A single stream of recorded sound with a location in a sound field or a signal that has been stored on media.

AVC High

Advanced Video Coding (H.264 or MPEG-4 Part 10 AVC) is a motion-compensation based video compression standard. As of 2014, it is one of the most commonly used formats for the recording, compression, and distribution of video content.

The standard defines a set of capabilities, which are referred to as profiles, targeting specific classes of applications. This allows a decoder to recognise the requirements to decode that specific stream. The HIGH profile is primary profile for broadcast and disc storage applications.

AVI

Audio-Video Interleave – a file type developed by Microsoft which combines audio and video with varying degrees of resolution and compression.

Bit depth

The number of bits used to represent each pixel in an image or the total number of bits used multiplied by the number of colour channels.

Chroma subsampling

Chroma subsampling is the practice of encoding images by implementing less resolution for chroma information than for luma information, taking advantage of the human visual system's lower acuity for colour differences than for luminance.

Codec

A codec is a software or hardware application that compresses and decompresses data, combining the functions of an encoder and decoder.

Colour space

A geometric representation of colours in space that can be visually perceived or generated using a particular colour model such as RGB or CMYK.

Compression

Re-encoding data so that it reduces the amount of information required compared to the same data uncompressed. May be lossy or lossless.

Derivative

Derivative files are secondary items produced from the master file. An access file is considered to be a derivative file.

DPX ( SMPTE-268 2003) uncompressed

Digital Picture Exchange (DPX) is a common file format for digital intermediate and visual effects work as defined by the SMPTE standard (268M-2003).

Encoding

A system that modifies a signal prior to recording. Encoding is the process of converting data from one form to another.

Frame rate

Frame rate is expressed in frames per second or fps. It is the rate at which continuous still images (frames) appear on a display.

JPEG

JPEG is a commonly used method of lossy compression for digital images.

MFX OP-1a

Material Exchange Format (MXF) is a container format for professional digital video and audio media defined by a set of SMPTE standards which supports a number of different streams of coded video and audio formats, together with metadata which describes the material contained within the MXF file.

MJPEG2000

Motion JPEG 2000 (MJ2 or MJP2) is a file format for motion sequences of JPEG 2000 images and associated audio, based on the MP4/QuickTime format.

MPEG 4 Base Media / Version 2

MPEG-4 is a method of defining compression of audio and visual digital data. It was introduced in late 1998 and designated a standard for a group of audio and video coding formats and related technology agreed upon by the ISO/IEC Moving Picture Experts Group (MPEG) under the formal standard ISO/IEC 14496.

MPEG-4 provides a large and rich set of tools for encoding. Subsets of the MPEG-4 tool sets have been provided for use in specific applications. These subsets, called 'Profiles', limit the size of the tool set a decoder is required to implement.

NTSC

Broadcasting system used in North America, Canada and the Middle East.

PAL

Broadcasting system used in Australia, New Zealand and other countries.

PDF

Portable Document Format (PDF) is a file format developed by Adobe, used to present and exchange documents, independent of software, hardware, or operating system. PDF is now an open standard maintained by the International Organization for Standardization.

PDF/A

PDF/A is an ISO-standardised version of the Portable Document Format (PDF). PDF/A differs in that it has been developed for archiving and the long-term preservation of electronic documents. Features present in PDF unsuitable for long-term archiving have been removed.

Raw file

An uncompressed, unprocessed file originating directly from the camera or scanning equipment.

Resolution

This term can describe either how many pixels a monitor can display or how fine a printer can print.

RGB

The RGB colour model is an additive colour model in which red, green and blue light are used to produce a wide range of colours.

Sampling frequency

The frequency (or rate) at which an analogue signal is sampled

TIFF

Tagged Image File Format – is a popular format for storing raster image data and is specified in TIFF Revision 6.0 from Adobe Systems. It has the ability to store image data in a lossless format.

YUV

The YUV model defines a colour space in terms of one luma (Y) and two chrominance (UV) components. The YUV colour model is used in the PAL composite colour video standard. Previous black-and-white systems used only luma (Y′) information. Colour information (U and V) was added separately via a sub-carrier so that a black-and-white receiver would still be able to receive and display a colour picture transmission in the receiver's native black-and-white format.

Copyright National Archives of Australia 2019