Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.
Digital Images and Scanning
Josh Hickman
WiLSWorld, 22 July 2015
Digital Images: Basic Concepts
• Pixels = smallest units of information that make up an image; arranged in an array
• Reso...
Digital Images: Basic Concepts
• File Size
– Height (pixels) x Width (pixels) x
[Bit Depth/8] = file size (bytes)
• Color ...
Resolution
• Expressed as points per inch (ppi) or as pixel
dimensions
• Higher resolution allows more detail, to an exten...
72 ppi 300 ppi 800 ppi
Source: Voight, R. (1930). "Setting up camp in Sahara" [Photograph]. Voight, Robert. Courtesy of Be...
1200 ppi 2400 ppi
The original photograph is about 2.75 x 4.5 in.
Source: Voight, R. (1930). "Setting up camp in Sahara" [...
Selecting a scan resolution
4000 pixels on the long edge of the digital image
• Select scan resolution to achieve this res...
Selecting a scan resolution
Selecting a scan resolution
The Histogram
Master and Derivative Images
Derivative Images
Service master images with further editing for
display (print, online, etc....
Scanning
Photo courtesy of Beloit College Archives.
Scanning
Goal is to achieve
these levels on the
Kodak Q-13 Gray
Scale across each
color channel:
A: 239-247
M: 100-108
19:...
An accurate image
Photo courtesy of Beloit College Archives.
A clipped image
Photo courtesy of Beloit College Archives.
Another inaccurate image
Photo courtesy of Beloit College Archives.
Histogram gaps
Photo courtesy of Beloit College Archives.
Fun with histograms
Fun with histograms
Fun with histograms
Source: Welcoming the Touareg chiefs -- Insalah by W. Bradley Tyrrell (1925). Courtesy
of Beloit Colle...
Flatbed Scanners
Beyond the basics, consider….
• Document/transparency size
• Optical resolution (vs. interpolated)
• Dyna...
Flatbed Scanners
Source: Taipei IT Month Epson V370 Photo By Solomon203
(Own work) [CC-BY-SA-3.0
(http://creativecommons.o...
Flatbed Scanners
• Epson Perfection v850 Pro (~$850)
• 6400 optical resolution
• 4.0 dMax
• Includes SilverFast SE Plus an...
Other Scanners
• Plustek OpticFilm 8200i (~$480)
• 7200 resolution
• Includes SilverFast Ai
• 35 mm negatives and slides
•...
Image Editing Software
• Adobe Photoshop Elements
• Adobe Photoshop Creative Cloud (CC)
• Adobe Creative Suite (CS)
– Phot...
Further reading
Bibliographic Center for Research and CDP Digital Imaging Best Practices
Working Group. (2008). BCR’s CDP ...
Thanks!
Josh Hickman, MLIS
608-363-2246
hickmanj@beloit.edu
Upcoming SlideShare
Loading in …5
×

Digitization Basics for Archives and Special Collections – Part 1: Select and Scan

1,164 views

Published on

Josh Hickman, Digital Resources Librarian, Beloit College
This is the first part of a two-part, full-day workshop introducing the core elements of creating digital collections of historic photographs, documents and other archival materials. Part 1 focuses on selecting materials to digitize and the basics of reformatting. We’ll start with some recommendations for planning a successful project and consider how your digital collections can fit into the statewide and national landscape of digital content. We’ll discuss copyright concerns in order to help you answer the question “CAN I put this online?” And we’ll explore the vocabulary of digital images, including pixels, resolution and bit depth as well as tools and best practices for scanning photographs and documents.

Published in: Education
  • Be the first to comment

Digitization Basics for Archives and Special Collections – Part 1: Select and Scan

  1. 1. Digital Images and Scanning Josh Hickman WiLSWorld, 22 July 2015
  2. 2. Digital Images: Basic Concepts • Pixels = smallest units of information that make up an image; arranged in an array • Resolution = expressed in pixels per inch or as the pixel dimensions of an image • Bits = smallest units of info that can be understood by a computer; 2 values (ON or OFF, 1 or 0, BLACK or WHITE) • Bit Depth = number of bits assigned per pixel; determines the number of colors available to represent the original – 2 bits = 4 shades (2^2) – 8 bits = 256 colors (2^8)  grayscale – 24 bits = millions of colors (2^24)  color images – In RGB images, bits are divided among the 3 channels… 8 bits for RED 8 bits for GREEN 8 bits for BLUE
  3. 3. Digital Images: Basic Concepts • File Size – Height (pixels) x Width (pixels) x [Bit Depth/8] = file size (bytes) • Color Space – System for describing colors numerically – AdobeRGB v. sRGB Source: Colorspace by Cpesacreta [Image]. CC BY 2.5 <http://creativecommons.org/licenses/by/2.5/>. Retrieved from <http://en.wikipedia.org/wiki/Color_space#mediaviewer/File:Colorspace.png>
  4. 4. Resolution • Expressed as points per inch (ppi) or as pixel dimensions • Higher resolution allows more detail, to an extent Source: Voight, R. (1930). "Setting up camp in Sahara" [Photograph]. Voight, Robert. Courtesy of Beloit College Archives. Retrieved from http://dcms.beloit.edu/cdm/ref/collection/african/id/171
  5. 5. 72 ppi 300 ppi 800 ppi Source: Voight, R. (1930). "Setting up camp in Sahara" [Photograph]. Voight, Robert. Courtesy of Beloit College Archives. Retrieved from http://dcms.beloit.edu/cdm/ref/collection/african/id/171
  6. 6. 1200 ppi 2400 ppi The original photograph is about 2.75 x 4.5 in. Source: Voight, R. (1930). "Setting up camp in Sahara" [Photograph]. Voight, Robert. Courtesy of Beloit College Archives. Retrieved from http://dcms.beloit.edu/cdm/ref/collection/african/id/171
  7. 7. Selecting a scan resolution 4000 pixels on the long edge of the digital image • Select scan resolution to achieve this result • For a printed image, 300 ppi is optimal A digital image with 4000 pixels on the long edge will be… • 13 inches long at 300 ppi • 27 inches long at 150 ppi • 5 inches long at 800 ppi Digital images do not have an absolute size!
  8. 8. Selecting a scan resolution
  9. 9. Selecting a scan resolution
  10. 10. The Histogram
  11. 11. Master and Derivative Images Derivative Images Service master images with further editing for display (print, online, etc.) Lossy compression (i.e. JPG) Service Master Images Edited version of archival master Edits can be stored as Photoshop layers Archival Master Images Highest quality affordable Lossless compression, non- proprietary formats (i.e.,TIFF) Unedited
  12. 12. Scanning Photo courtesy of Beloit College Archives.
  13. 13. Scanning Goal is to achieve these levels on the Kodak Q-13 Gray Scale across each color channel: A: 239-247 M: 100-108 19: 8-16 Photo courtesy of Beloit College Archives.
  14. 14. An accurate image Photo courtesy of Beloit College Archives.
  15. 15. A clipped image Photo courtesy of Beloit College Archives.
  16. 16. Another inaccurate image Photo courtesy of Beloit College Archives.
  17. 17. Histogram gaps Photo courtesy of Beloit College Archives.
  18. 18. Fun with histograms
  19. 19. Fun with histograms
  20. 20. Fun with histograms Source: Welcoming the Touareg chiefs -- Insalah by W. Bradley Tyrrell (1925). Courtesy of Beloit College Archives <http://dcms.beloit.edu/cdm/ref/collection/african/id/409>
  21. 21. Flatbed Scanners Beyond the basics, consider…. • Document/transparency size • Optical resolution (vs. interpolated) • Dynamic range (dMax) • Supported bit depths • Added features and software No one scanner will be perfect for every situation. Keep in mind the material you expect to scan and thoroughly evaluate the specifications of each scanner to make sure it can handle your items!
  22. 22. Flatbed Scanners Source: Taipei IT Month Epson V370 Photo By Solomon203 (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons <http://upload.wikimedia.org/wikipedia/commons/5/56/Taip ei_IT_Month_Epson_V370_Photo_20131202.jpg> • Epson Perfection V370 (~$120) • 4480 optical resolution • 3.2 dMax • Epson Perfection V550 (~$200) • 6400 optical resolution • 3.4 dMAx • These scanners have limited transparency scanning capability. If you’ll be working with negatives, slides, glass plates, etc., be sure that these scanners can handle the format and size of your transparencies!
  23. 23. Flatbed Scanners • Epson Perfection v850 Pro (~$850) • 6400 optical resolution • 4.0 dMax • Includes SilverFast SE Plus and X-Rite i1 calibration • 8 x 10 in. transparency area • Epson Expression 11000XL (~$2600) • 2400 optical resolution • 3.8 dMax • 12 x 17 in. document size • Includes SilverFast Ai and IT8 calibration charts
  24. 24. Other Scanners • Plustek OpticFilm 8200i (~$480) • 7200 resolution • Includes SilverFast Ai • 35 mm negatives and slides • Planetary scanners • Konica Minolta PS7000C MK II • DIY Book Scanners • Caution: purchasing components can be expensive • http://www.diybookscanner.org Source: Slide scanner By HandigeHarry (Own work) [Public domain], via Wikimedia Commons <http://upload.wikimedia.org/wikipedia/commons /f/f5/Slide_scanner.JPG>
  25. 25. Image Editing Software • Adobe Photoshop Elements • Adobe Photoshop Creative Cloud (CC) • Adobe Creative Suite (CS) – Photoshop – Bridge, Lightroom, Illustrator, etc. • Corel Paint Shop Pro • GIMP
  26. 26. Further reading Bibliographic Center for Research and CDP Digital Imaging Best Practices Working Group. (2008). BCR’s CDP digital imaging best practices, version 2.0. Aurora, CO.: Bibliographic Center for Research]. Retrieved July 8, 2015, from http://mwdl.org/docs/digital-imaging-bp_2.0.pdf Kennedy, J. (2012). Preserving history: how to digitally archive and share historical photographs, documents, and audio recordings. Retrieved June 29, 2014, from http://archivehistory.jeksite.org/ Puglia, Steven T, Jeffrey Reed, and Erin Rhodes, United States and National Archives and Records Administration. Technical Guidelines for Digitizing Archival Materials for Electronic Access: Creation of Production Master Files--Raster Images. Washington, D.C.: Digital Library Federation, 2005. Retrieved July 8, 2015, from http://www.digitizationguidelines.gov/guidelines/digitize-technical.html
  27. 27. Thanks! Josh Hickman, MLIS 608-363-2246 hickmanj@beloit.edu

×