{"id":3995,"date":"2016-06-17T18:43:45","date_gmt":"2016-06-17T22:43:45","guid":{"rendered":"http:\/\/blogs.library.duke.edu\/bitstreams\/?p=3995"},"modified":"2016-06-18T19:12:28","modified_gmt":"2016-06-18T23:12:28","slug":"fadgi-still-image-standard-isnt-just-file-specs","status":"publish","type":"post","link":"https:\/\/blogs.library.duke.edu\/bitstreams\/2016\/06\/17\/fadgi-still-image-standard-isnt-just-file-specs\/","title":{"rendered":"The FADGI Still Image standard: It isn\u2019t just about file specs"},"content":{"rendered":"

In previous posts<\/a> I have referred to the FADGI standard<\/a> for still image capture when describing still image creation in the Digital Production Center<\/a> in support of our Digital Collections Program<\/a>.\u00a0 We follow this standard in order to create archival files for preservation, long-term retention and access to our materials online.\u00a0 These guidelines help us create digital content in a consistent, scalable and efficient way.\u00a0 The most common cited part of the standard is the PPI guidelines for capturing various types of material.\u00a0 It is a collection of charts that contain various material types, physical dimensions and recommended capture specifications.\u00a0 The charts are very useful and relatively easy to read and understand.\u00a0 But this standard includes 93 \u201cexciting\u201d pages of all things still image capture including file specifications, color encoding, data storage, physical environment, backup strategies, metadata and workflows.\u00a0 Below I will boil down the first 50 or so pages.<\/p>\n

The FADGI standard was built using the NARA Technical Guideline for Digitizing Archival Materials for Electronic Access: Creation of Production Master Files \u2013 Raster Images<\/a> which was established in 2004.\u00a0 The FADGI standard for still image capture is meant to be a set of best practices for cultural heritage institutions and has been recently updated to include new advances in the field of still image capture and contains more approachable language than its predecessor.\u00a0\"FADGI1\"<\/a><\/p>\n

Full disclosure<\/strong>. Perkins Library and our digitization program didn\u2019t start with any part of these guidelines in place.\u00a0 In fact, these guidelines didn\u2019t exist at the time of our first attempt at in-house digitization in 1993.\u00a0 We didn\u2019t even have an official digitization lab until early 2005.\u00a0 We started with one Epson flatbed scanner and one high end CRT monitor.\u00a0 As our Digital Collections Program has matured, we have been able to add equipment and implement more of the standard starting with scanner and monitor calibration and benchmark testing of capture equipment before purchase.\u00a0 We then established more consistent workflows and technical metadata capture, developed a more robust file naming scheme, file movement and data storage strategies.\u00a0 We now work hard to synchronize our efforts between all of the departments involved in our Digital Collections Program. \u00a0We are always refining our workflows and processes to become more efficient at publishing and preserving Digital Collections.\"epson\"<\/a><\/p>\n

Dive Deep<\/strong>.\u00a0 For those of you who would like to take a deep dive into image capture for cultural heritage institutions, here <\/a>is the full standard.\u00a0 For those of you who don\u2019t fall into this category, I\u2019ve boiled down the standard below.\u00a0 I believe that it\u2019s necessary to use the whole standard in order for a program to become stable and mature.\u00a0 As we did, this can be implemented over time.\u00a0\"dive\"<\/a><\/p>\n

Boil It Down. <\/strong>The FADGI standard provides a tiered approach for still image capture, from 1 to 4 stars, with four stars being the highest.\u00a0 The 1 and 2 star tiers are used when imaging for access and tiers 3 and 4 are used for archival imaging and preservation at the focus.<\/p>\n

The physical environment: The environment should be color neutral. \u00a0\u00a0Walls should be painted a neutral gray to minimize color shifts and flare that might come from a wall color that is not neutral.\u00a0 Monitors should be positioned to avoid glare on the screens (This is why most professional monitors have hoods).\u00a0 Overhead lighting should be around 5000K (Tungsten, florescent and other bulbs can have yellow, magenta and green color shifts which can affect the perception of the color of an image).\u00a0 Each capture device should be separated so that light spillover doesn\u2019t affect another capture device.<\/p>\n

Monitors and Light boxes and viewing of originals: Overhead light or a viewing booth should be set up for viewing of originals and should be a neutral 5000K.\u00a0 A light box used for viewing transmissive material should also be 5000K.<\/p>\n

Digital images should be viewed in the colorspace they were captured in and the monitor should be able to display that colorspace.\u00a0 Most monitors display in the sRGB colorspace. However, professional monitors use the AdobeRGB colorspace which is commonly used in cultural heritage image capture.\u00a0 The color temperature of your monitor should be set to the Kelvin temperature that most closely matches the viewing environment.\u00a0 If the overhead lights are 5000K, then the monitor\u2019s color temperature should also be set to 5000K.<\/p>\n

Calibrating packages that consist of hardware and software that read and evaluate color is an essential piece of equipment.\u00a0 These packages normalize the luminosity, color temperature and color balance of a monitor and create an ICC display profile that is used by the computer\u2019s operating system to display colors correctly so that accurate color assessment can be made.\u00a0\"gedT013\"<\/a><\/p>\n

Capture Devices: The market is flooded with capture devices of varying quality.\u00a0 It is important to do research on any new capture device.\u00a0 I recommend skipping the marketing schemes that tout all the bells and whistles and just stick to talking to institutions that have established digital collections programs.\u00a0 This will help to focus research on the few contenders that will produce the files that you need.\u00a0 They will help you slog through how many megapixels are necessary, what lens are best for which application, what scanner driver is easiest to use while balanced with getting the best color out of your scanner.\u00a0 Beyond the capture device, other things that come into play are effective scanner drivers that produce the most accurate and consistent results, upgrade paths for your equipment and service packages that help maintain your equipment.<\/p>\n

Capture Specifications: I\u2019ll keep this part short because there are a wide variety of charts covering many formats, capture specifications and their corresponding tiers.\u00a0 Below I have simplified the information from the charts.\u00a0 These specification hover between tier 3 and 4 mostly leaning toward 4.<\/p>\n

Always use a FADGI compliant reference target at the beginning of a session to ensure the capture device is within acceptable deviation.\u00a0 The target values differ depending on which reference targets are used.\u00a0 Most targets come with a chart representing numerical value of each swatch in the target.\u00a0 Our lab uses a classic Gretagmacbeth target and our acceptable color deviation is +\/- 5 units of color.<\/p>\n

Our general technical specs for reflective material including books, documents, photographs and maps are:<\/p>\n