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Guide to FADGI: What It Is and How the Four-Star System Works

Every organization wants to be sure that its digitized materials meet certain quality standards.

But the stakes are even higher for libraries, archives, museums, and other institutions that are responsible for safeguarding cultural heritage materials for future generations.

That’s why various U.S. federal agencies came together to establish guidelines and specifications for digitizing cultural heritage materials.  Called the Federal Agencies Digital Guidelines Initiative (FADGI), the collaborative effort aims to ensure that materials digitized by agencies and the broader cultural heritage community meet standards for quality, accessibility, and long-term preservation.

This article takes a deep dive into FADGI and how its four-start rating system works.

What do the FADGI star ratings stand for?

FADGI uses a star rating system to indicate the level of compliance with its guidelines.

Ranging from one to four stars, the ratings provide a standardized way to assess the quality and suitability of equipment and processes for digitizing cultural heritage materials.  The more stars, the higher the level of compliance with FADGI’s guidelines and specifications.  The ratings are assigned based on an evaluation of various factors, such as image resolution, color accuracy, and file formats.

Here’s an overview of what each star rating signifies:

  • One Star: Basic Compliance.  A one-star rating indicates minimal compliance with FADGI’s guidelines.  While the equipment and processes with a one-star rating may meet basic FADGI standards, they may have limitations or deficiencies in quality or accuracy.  Equipment or processes with a one-star FADGI rating may be suitable for basic digitization tasks but may not be sufficient for demanding or high-quality reproduction projects.
  • Two Stars: Good Compliance.  A two-star rating indicates a moderate level of compliance with FADGI specifications.   Equipment and processes with a two-star rating demonstrate satisfactory performance and adherence to most of FADGI’s recommended requirements for quality and accuracy and are suitable for a wide range of digitization projects.
  • Three Stars: Excellent Compliance.  A three-star rating indicates a high level of compliance with FADGI guidelines.  Equipment and processes with a three-star rating meet most of FADGI’s recommended requirements and demonstrate superior performance in terms of image quality, color accuracy, and preservation standards.  Solutions with a three-star FADGI rating are suitable for demanding digitizing projects requiring high-quality reproduction.
  • Four Stars: Exemplary Compliance.  A four-star rating indicates that equipment and processes exceed FADGI’s requirements and demonstrate outstanding performance in all aspects of digitization, for the most demanding applications.  Equipment and processes with a four-star FADGI rating produce digitized materials of the highest quality and fidelity.

While the specific criteria used to assign star ratings may vary depending on the context and the requirements of a digitization project, the star rating system provides a standardized way to assess the compliance of digitization equipment and processes with the guidelines set forth by FADGI.

How does the FADGI star system work?

FADGI’s star-rating system can be invaluable in helping organizations evaluate the quality, accuracy, and suitability of digital solutions for their needs.  Here’s how the FADGI star-rating system works:

  • Testing.  Equipment and processes are tested to determine their level of compliance with FADGI guidelines for image quality, color fidelity, and preservation standards.  The testing may include standardized test targets, reference materials, or sample digitization projects.
  • Scoring.  Equipment and processes are scored according to their performance during testing relative to FADGI guidelines.  Numerical scores or ratings are assigned based on criteria such as image resolution, color accuracy, and preservation of metadata.  The scores are then analyzed to determine a level of compliance with FADGI guidelines and specifications.
  • Star rating.  Once the scoring and analysis is completed, equipment and processes are assigned a star rating based on their level of compliance with FADGI guidelines.
  • Documentation.  The results of the testing, scoring, and assignment of a star rating are documented.  The documentation may include detailed reports, summaries, or certificates indicating the level of compliance with FADGI guidelines and the corresponding star rating.

The star-rating system provides a valuable framework for evaluating equipment and processes based on their adherence to guidelines and specifications for digitizing cultural heritage materials.

What are the FADGI star rating requirements?

So, how are FADGI star ratings assigned?

FADGI star ratings are typically assigned based on a comprehensive evaluation of digitization equipment and processes against FADGI’s established guidelines, considering a variety of factors.

Here are some common criteria that influence the assignment of star ratings.

  • Image resolution.  FADGI guidelines typically specify minimum requirements for image resolution, measured in dots per inch (DPI) or pixels per inch (PPI).  Higher resolutions are generally preferred for capturing fine details and ensuring the fidelity of digitized materials.
  • Color accuracy.  FADGI emphasizes the importance of accurate color reproduction in digitized materials.  Color accuracy is assessed based on adherence to recognized color standards and the ability to faithfully reproduce the colors present in the original materials.
  • Dynamic range.  Dynamic range refers to the ability of digitization equipment and processes to capture and represent the full range of tones and shades present in the original materials. Digitized materials should retain sufficient detail in both highlights and shadows.
  • File formats.  FADGI encourages the use of open and standardized file formats (such as TIFF and JPEG formats) for storing digital materials.  Compliance with standard file formats ensures interoperability, long-term accessibility, and preservation of digital collections.
  • Metadata standards.  FADGI guidelines include requirements for metadata standards, such as the use of standardized vocabularies and metadata schemas. Compliance with metadata standards facilitates discovery, retrieval, and long-term management of digital collections.
  • Quality control.  FADGI emphasizes the importance of quality control measures throughout the digitization process.  These measures may include procedures for calibrating equipment, monitoring image quality, inspecting images, and ensuring consistency across multiple scans.
  • Preservation standards.  Preservation considerations are integral to FADGI guidelines and specifications. Compliance with preservation standards encompasses factors such as file format sustainability, digital storage best practices, and adherence to archival principles.

These are some of the key considerations that may influence the assignment of FADGI star ratings.


Ensuring the long-term accessibility and integrity of cultural heritage materials is critical for archives, museums, libraries, and other institutions in today’s digital age.  By adhering to FADGI’s star-rating system, institutions can safeguard valuable historical materials for future generations.

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