1. Presented by: MU Libraries Digitization MOBIUS Annual Conference 2012 Brian Cain Felicity Dykas Regina Guccione Elaine Huntsucker

2.  400 DPI .TIFF  Raster / Bitmap  RGB Color

3. 160,000 Pixels DP I DotsPerInch

4.  RED  GREEN  BLUE  CYAN  YELLOW  BLACK  MAGENTA Pixel Dot

6.  An image that is composed of individual elements e.g. arc, line, polygon, that have their own attributes.

8.  400 DPI .TIFF  Raster / Bitmap  RGB Color

9. 200 DPI (DOTS PER INCH) 400 DPI (DOTS PER INCH)

10. 200 DPI400 DPI

11. 1 2 3 4 5 6 7 8 9 10 1 2 3 4 6 7 8 9 10

12. The number of bits used to indicate the color of a single pixel in a bitmapped image. 1 bit = 2 1 = 2 color channels The more bits of information per pixel, the more available colors and more accurate the color representation. An image with a bit depth of 1 has pixels with only two possible values: black and white.

13. 8 BIT DEPTH24 BIT DEPTH Both of these images are 400dpi

14. 8 Red Components X 8 Green Components X 4 Blue Components = 256 RGB Color Variations 8 bit = 2 ⁸ = 256

15. 256 Red Components X 256 Green Components X 256 Blue Components = 16,777,216 RGB Color Variations 24 bit = 2 24 = 16,777,216

16.  Two most common color modes are RGB and CMYK  RGB (Red, Green, Blue color channels) is an additive color process (red+green+blue=white)  CMYK (Cyan, Magenta, Yellow, blacK color channels) is a subtractive color process (cyan+magenta+yellow=black)

17.  Most common color mode for digital images  Produced from the measurement for each pixel of the amount of light passing through RGB filters in imaging hardware  Creates a color image through a mixture of each color channel depending on these measurements (0-255 for each RGB value at 24 bit)

18. (255-0-0) RGB (0-255-0)(0-0-255) 24 bit image: 256 X 256 X 256 = 16.8 million possible colors

19. NO Red channel NO Red and Green NO Green Regular color NO Blue and Red NO Blue NO Blue and Green

20.  More related to prepress work and printing  Method used in inkjet and laser printers for creating color images  Not a common color mode for digital images, usually a conversion from RGB

21.  Bitonal, binary, black and white, or 1-bit monochrome image  Records 1-bit of information (0, 1) depending on whether the pixel is light or dark

22.  Assigns pixels shades of gray on gradient between white and black  Grayscale 8 or 16 bit determines amount of shades of gray available

23.  What is a file format? File formats include.tiff,.jpeg,.pdf, essentially specific structures for the encoding of data that allows software to interpret and display the image. File formats usually include image data and metadata about the file itself and the image.  What is compression? Compression is the process of reducing the amount of data stored for a digital image file, usually utilizing some sort of algorithmic formula. Depending on the method, compression can either be “lossless” or “lossy”, meaning reconstruction of the original digital image data may or may not be possible.

24.  Adoption and accessibility  Metadata creation  Range of functionality and flexibility  Long-term access and support  Preservation and storage considerations What are some important considerations when choosing a file format?

25.  Software upgrades no longer support file format  File format itself is updated and legacy files become obsolete  Slow adoption and limited software options  Functionality no longer current with contemporary environment  File format is no longer supported or is withdrawn due to market forces What problems may arise with file formats?

26.  Not any one format, proprietary format for each camera  Holds all the data captured by the camera sensor  Typically only understandable by camera-specific software, some third-party support available  Unsure long-term viability and support for each format  DNG (Digital negative) format by Adobe possible solution for universal RAW data conversion

27.  Royalty free file format with a long history and wide adoption  Can be thought of as a “file wrapper” that is able to preserve all image data and tags found in raster and vector images  Very flexible format that accommodates full RGB colors, high bit-depth, all associated metadata, and any image resolution  Capable of storing lossless images Tagged Image File Format (TIFF)  Can result in very large file sizes  Rights held by Adobe

28.  JPEG was designed to limit file size for storage and for quick display  Uses “lossy” compression algorithms to reduce amount of image data  More limited color data (not full RGB) and reduced spatial resolution  Wide adoption and well supported  Smaller file size, however this is due to permanently discarded image data Joint Photographic Experts Group

29.  Update of JPEG format, described as “lossless” (debatable)  Uses Wavelet compression techniques superior to regular JPEGs, however color data is still lost and spatial resolution data is modified in the compression process Master Display Thumbnail  Because of the nature of the format, it can store and deliver varying versions of the image from one file  Needs specialized software to view and use JPEG2000, relatively low adoption and use rate

30.  Originally a proprietary format of Adobe, but was released as an open standard in 2008  Meant as a “wrapper” with structured page description for complex documents created using multiple component types (text, images, etc.). Not consistent encoding across all iterations of PDF software  Widely adopted and used, however varying forms of image compression and manipulation occur when saving as a PDF  PDF/a is an offshoot of PDF v1.4, meant for long-term preservation and is more restrictive in the content and types of structured data saved in the file Portable Document Format

31.  GIF: only supports 8 bit (256 colors), lossy compression produces small file sizes, wide adoption on web  PNG: GIF replacement, supports true color (24 bit +), no CMYK support, lossless compression, not as commonly used as GIFs but growing  BMP: very simple format, records location of pixel and its color (up to 24-bit), does not store metadata  PSD: proprietary Adobe Photoshop File, dependant on Adobe software and support

32.  Comparison between TIFF, PNG, GIF and JPEG file size for 400 ppi color image TIFF JPEG/GIF PNG

33. Color  Comparison between color, grayscale and bitonal TIFF files at 400 ppi resolution Grayscale Bitonal

34. 400 ppi 200 ppi 100 ppi  Comparison between 24 bit color TIFF files at 400, 200 and 100 ppi resolutions

35.  It depends …  Try for good versus best  Establish acceptable minimum level of work, and make it the benchmark. (Meissner, 2011, slide 9)

36.  Priority is to create and preserve a high- quality master copy of a digital image  Priority is to provide access to users

37.  Create a fully documented high-quality ‘digital-master’ from which all other versions … can be derived.  Digital master  highest resolution and bit depth that is both affordable and practical  preserves to the greatest extent possible the authenticity and integrity of the original information. (Hughes, 2004, p. 166-167)

38. More Product, Less Process Maximize user access (preeminent goal) Golden minimum “good enough” digitization is realistic Arrange, describe and digitize at a common aggregate level Reserve exception digitization effort only when warranted Accomplish more digitization by trying to do less (Elings)

39. Then …Now … CraftAssembly Line Rigorous quality controlQuality control not as rigorous Few highly skilled students working More students working more hours Digital image editingConsistency in product produced, not perfection Completing 17-39 books [per month] Completing 500-800 books [per month] (Henry, 2008)

40.  Goals and priorities  Audience  Material  Institutional resources

41. o Goals and priorities of the institution and the project o Grant requirements o Requirements of partners o Long-term plans o Fit the file to the purpose (Kenney, 2000, p. 105) o Archival/preservation copy versus access copy

42. o Target user needs o Will users want to zoom in and view detail? o Will users need OCR to search the content? o Will users want to print the digital image? o Will users be interested in the artifact as well as the content? o What image performance is required?

43. o Text versus graphics/pictures o Text with a crisp font versus handwritten text o Black and white versus color o Condition of items o Need to retain the digitized items

44. o People and skills o Equipment / technology o Digitization equipment o Infrastructure / platforms for access and storage o Time and production targets o Constraints imposed by source material (condition and types)

45. Factors that will influence decisions [throughout the digital life cycle] – The reasons for digitization – The materials to be digitized, especially their condition and informational content – The level of fidelity to the original that is required – The technical and financial resources that are available to the project, and the scale of the project – The potential uses and users of the digital objects – Any specific desired outcomes for the physical objects that are to be digitized. (Hughes, 2004, p. 165)

46.  At times, your choice comes down to time and money: convert fewer items at a high level or more items at reduced quality. (Kenney, p. 25)  Strive for good quality that meets user needs  Whatever you decide, be consistent  Document your standards / criteria

47.  A frequent concern is how to achieve the proper balance between quality and rate of production. Having a clear vision of the use of the digital materials and the quality required will help to focus such decisions. (Hughes, 2004, p. 165-166)  Compromises in quality are acceptable when the purpose of imaging is a matter of access only and preservation of information of the original has been assured through conservation or preservation reformatting. However, when the intent of digitization is the reproduction or replacement of the original, the highest possible resolution and tonality must be applied. (Ballinger, p. 160)

48.  Tiff, uncompressed and unedited  The standby (Nadal, 2012b)  Various dpi: 300-600; choose the highest possible for type of material  24-bit color  PDF/A  Very preservable (Nadal, 2012b)  Digital negative  May be valuable as a digital preservation format for the specific use-case of born-digital photography (Nadal, 2012b)

49. Long-term access will likely include the need to o Refresh – moving files from one physical storage medium to another to avoid obsolescence or degradation of the storage medium o Migration – moving files from one encoded format to another o Emulation – develop new tools that will re-create the conditions under which the original data were created; similar to migration, but focuses on the application software o (Hughes, 2004, p. 205)

50. Questions?