Technology Considerations

for Developing a Digitization Workflow Strategy

04/22/23 Digital Imaging Workshop 1

Workshop participants will understand the technology issues involved in

converting, storing, and maintaining analog materials in digital format.


Overview the 6 Stages of the Digitization Chain

In-depth discussion about each stage of the Digitization Chain

Review Issues involved in establishing a technology process in your digitization workflow

Group Exercise


Be able to Identify the 6 stages of the Digitization Chain

Understand at least 3 elements of each stage of the Digitization Process

By the end of the session, be able to Assign appropriate IT, staff, and resources to your digitization workflow



THE FULL DIGITIZATION CHAIN

Benchmarking

source document

detailwidth

height

Scanning• capture• file formatting• compression• metadata creation• quality control• authentication

• quality benchmarks• dimensions of document and its significant detail(s)• other document attributes• quality index formulas

• storage and backup• scaling for access (derivatives)• error detection and correction• migration

• servers• protocols• authorization• scalable architecture

File Management Networking

Display Printing

reformatted document

• decompression• integration with image browser• magnification

• decompression• page language interpretation• dithering• scaling

Main factors are: Color depth

▪ (1-bit) bitonal, (8-bit) or (16-bit) grayscale, or (24-bit) full color Resolution

▪ Higher resolution = higher file size Compression

▪ More compression = more lost information Purpose or use of digital images

▪ Deciding whether you are digitizing for presentation or archival purposes


Benchmarking

source document

detailwidth

height

• quality benchmarks• dimensions of document and its significant detail(s)• other document attributes• quality index formulas


Scanners Drum Scanner 35mm Slide Scanner Flat-bed scanner

Digital Cameras


Scanning• capture• file formatting• compression• metadata creation• quality control• authentication

High-end Howtek, Inc. Drum Scanner

35mm Nikon Slide scanner Epson Expression 10000XL Flat-bed scanner

Canon EOS 30D Digital Camera

Image Capture▪ Scan paper-based materials up to 17.2” X 12.2”▪ Scan transparencies & film-based materials

using the Transparency Unit▪ Connect via USB & Firewire▪ Create scans up to 2400 Dpi Optical Resolution▪ 1 YR Limited Warranty▪ Scan using LaserSoft Imaging SilverFast Ai6

scanning software▪ Calibrate scanning software using a

MonacoEZcolor with Reflective IT8 Target



Adobe Photoshop CS3– Make image enhancements such as sharpening,

cropping, deskewing, descreening, and despeckling. Other adjustments are made here including contrast stretching using the histogram tool and minimal adjustments for tone and color.

– Save Master Image File as a TIFF with no compression.– Create and Save derivative Access files with minimal

compression.» Save in a lower resolution» Save as file type JPEG

Still Image* GIF, JPEG, JPEG 2000, MrSID, TIFF, CAM RAW

Textual PDF, XML, RTF, HTML, SGML, DOC


You might use up to four file formatsSave Preservation-quality images as

TIFF version 6.0 filesSave Access-quality images as JPEG

or JPEG 2000 filesSave derivative document files as

PDF’s and transcripts as .TXT filesSave Master text files as XML or RTF


Issues involved in deciding which compression algorithm to use: File size Quality of display image Fixed or multi-resolution capability


Our recommendations are to use the following: Lossless (LZW) compression for

preservation-quality images Lossy compression (JPEG) with a quality

measurement of 6 on a scale of 1-10 for access-quality images


Metadata Creation Manual or Automated

Types of metadata File naming schemes, file directory

structuring, (TIFF) file headers Administrative Descriptive Structural

Metadata Schemes & Element Sets Dublin Core, TEI and METS



Recommended file naming conventions Administrative metadata spreadsheet Dublin Core Metadata Element Set

Factors involved in image quality Strategy based on project goals Reference point Scope and methods of your quality

review QC environment System performance Codify your procedures



What is authentication?* System of verifying the identities of

networked users, clients, and servers without transmitting passwords over the internet.



firewall

Main features of a file storage/management system are: Provides searching tools Provides public and internal links to the

images/metadata Provides the control elements necessary for long-

term and short-term access


• storage and backup• scaling for access (derivatives)• error detection and correction• migration

File Management

Main features of a file backup system are: Provides protection from data loss or damage Promotes sustainability for managing digital

content over time Part of a comprehensive digitization workflow

strategy


What to do: Save digital images/metatada onto CD-

R’s/DVD’s Involve your IT people in decision-making

process Determine your storage needs during

selection and planning process▪ How many MB or GB storage will you need this

year, next year, or in 5 years▪ Who, What, When, How will you move digital

images from scanning workstation in Library across network to backup server?


CD-R’s/DVD’s can be used for storage

LOCKKS (Lots of Copies Keeps Stuff Safe) or Grid system


Issues involved in scaling derivative files for access: Speed delivery of digital images to users Quality of presentation Choice of file format




Where do errors occur in the digitization chain?

• Cataloging

- Incorrect metadata input through manual entry

• Image Capture

-Poor document quality at image capture

-Text recognition errors

CUL recommends a quality control strategy involving: Scheduled equipment calibration Periodic review of images/metadata Controlled scanning environment


Issues involved in File Migration: Recognizing that digital imaging is not

the final answer to your preservation needs

Digital images need to be migrated every (n) of years


You need to decide at what level of frequency you will review your digital images for loss of data.

Use a checksum to determine the extent of data loss.

File Folder management for your digital masters and derivatives


Collection name or Topic (i.e. ad_white or historical_photographs)

Tiffs Jpegs

Access image file (i.e. jpeg or gif as is displayed above)

Preservation quality images and Access images (i.e. preservation folder and an access folder)

Issues involved in networks User’s internet connection speed Delivery of digital images

▪ File formats▪ Compression▪ Scaling derivatives


• servers• protocols• authorization• scalable architecture

Networking

Project benchmarks for files types, compression, and scaling derivatives

Using CONTENTdm as our client/server content management solution Images are uploaded via an Acquisition Station Dublin Core, xml based Integrates texts, images, audio, and video Collaborative system Extensible with customizable web interfaces Custom Queries and Results (CQR) My Favorites light box with online slide-show,

compare, manipulate and save presentations for online or offline display


Acquisition Station & CONTENTdm▪ Must Download and Install Acquisition Station

on Workstation▪ Only 1 license per institution (but may

request more under special circumstances)▪ May request logins/passwords for multiple

users


Scalable architecture Image displays Number of files that can be served up Intuitive content management interface


Issues affecting display Type of monitor (CRT vs LCD, SVGA, or

XGA) Refresh rate (75Hz, 85Hz, or higher) Bit rate (18-bit for CRT’s, 24-bit for

LCD’s, millions of colors for SXGA)Monitor resolution is 72 dpi


Display

• decompression• integration with image browser• magnification

Computer workstation features Viewable size: 19” Aspect ratio: horizontal dimension

divided by vertical dimension – 5:4 Contrast ration: measurement in the

difference between whitest white and darkest black – 500:1

Color depth: 16.2 Million colors Refresh rate at max resolution: 75Hz


Issues involved in image presentation using image browsers: Limited raster file formats: GIF, JPEG, PNG Need for specialized viewers, applets, or

plug-ins Network connection speed


Recommended file formats: JPEG PDF


Decompression How will different printers interpret the image pixels

(standard desktop printers or large graphic plotters) Page language

PostScript 4.3 (Adobe) HP Epson Windows PRN

Interpretation Dithering -

Scaling Remember, images should be significantly larger in dpi

for print than for monitor display, but this produces larger file sizes.


Each institution should supply a color printer


Work with your IT department/work with your Library

Set up your equipmentStore your computer’s Ghost Image

DVD in a safe location in case of a computer crash

Manage computer and file Security Logins and passwords

Sample Workflow model from ASU


Calibrating your equipment [PDF]* Basic Production Steps Creating Compound Objects Master/Access Image Tables Naming your Digital Files Quality Assessment Survey & Guidelines Administrative Metadata Spreadsheet [MS

Excel] Installing the Acquisition Station &

Loading your First Image


*All files in Adobe PDF unless otherwise noted and located at:

http://hbculibraries.org/html/programs.html

Developing your digitization workflow plan Define project and institutional

goals/deliverables Under each bulleted item list available

technological resources/capabilities/persons responsible▪ Scanning▪ File management▪ Networking▪ Image display and delivery


Documents

Technology Considerations