Overview

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1. Optical media formats were conceived with data preservation in mind, but digital material stored on optical disc is now considered to be at high-risk of loss or degradation.
   
   
   1. Scratches from handling or faulty machines can result in data loss.
      
      
   2. Many discs are manufatured with low cost dyes and metals.
      
      
   3. Pens or markers with hard tips or solvents can affect the protective data layer.
      
      
   4. Optical discs can be affected by ambient heat and direct sunlight.
      
      
   5. Risk associated with the lack of expertise in identifying optical media formats.
      
      

2. Stability of optical discs depends on the type of disc and the combination of dyes and metals used to manufacture the disc:
   
   
   
   

   Info
   title Image source
   MAM-A, Inc. CD-R Dyes: How to Tell What's What. Accessed November 3, 2017.

   
   

3. Digital material stored on optical disc should be appraised or re-appraised to determine the nature and significance of the material and whether it has sufficient value to justify reformatting and long-term preservation as digital files.

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1. Red Book - IEC standard 60908:1999. Audio recording - Compact disc digital audio system.

CD-ROM

1. Yellow Book - ISO/IEC standard 10149:1995. Information technology -- Data interchange on read-only 120 mm optical data disks (CD-ROM)

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