For Developing a Digitization Workflow Strategy 9/15/2015 Digital Imaging Workshop 1.
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Transcript of For Developing a Digitization Workflow Strategy 9/15/2015 Digital Imaging Workshop 1.
Workshop participants will understand the technology issues involved in
converting, storing, and maintaining analog materials in digital format.
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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
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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
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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
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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
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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
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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
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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
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Issues involved in deciding which compression algorithm to use: File size Quality of display image Fixed or multi-resolution capability
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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
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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
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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
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What is authentication?* System of verifying the identities of
networked users, clients, and servers without transmitting passwords over the internet.
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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
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• 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
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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?
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CD-R’s/DVD’s can be used for storage
LOCKKS (Lots of Copies Keeps Stuff Safe) or Grid system
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Issues involved in scaling derivative files for access: Speed delivery of digital images to users Quality of presentation Choice of file format
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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
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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
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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
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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
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• 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
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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
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Scalable architecture Image displays Number of files that can be served up Intuitive content management interface
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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
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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
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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
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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.
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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
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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
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*All files in Adobe PDF unless otherwise noted and located at:
http://hbculibraries.org/html/programs.html