Page Contents 4 minute read.
Scanning Standards by Type of Material
Digital image collections incorporated into the UNT Libraries’ permanent collections must adhere to the minimum requirements given below. Depending on the specific objectives of the projects, higher resolutions may be desirable for some materials. Please note that this document is not intended to address all technical issues and does not describe the details of operational procedures. See project-specific guidelines for further information.
Text (Books)
| Image Types | Bit Depth | Color Space | Resolution (ppi) | Scale | File Format |
|---|---|---|---|---|---|
| B&W Text Only | 1-bit | Bitonal | 600ppi | 100% (1:1) | Tiff (uncompressed or lossless compression, no LZW) |
| B&W Text with Illustrations (Photos, Drawings, Plates, Charts) | 8-bit | Grayscale | 400ppi | 100% (1:1) | Tiff (uncompressed) |
| Text w/ Continuous-Tone Images & Photos (Color) | 24-bit | RGB | 400ppi | 100% (1:1) | Tiff (uncompressed) |
Documents (Handwritten, Ledgers, Receipts)
| Image Types | Bit Depth | Color Space | Resolution (ppi) | Scale | File Format |
|---|---|---|---|---|---|
| B&W Text Only* | 1-bit | Bitonal | 600ppi | 100% (1:1) | Tiff (uncompressed or lossless compression no LZW) |
| Handwritten Documents, Ledgers | 8-bit | Grayscale | 400ppi | 100% (1:1) | Tiff (uncompressed) |
| Correspondence, Letters | 24-bit | RGB | 400ppi | 100% (1:1) | Tiff (uncompressed) |
* We recommend scanning handwritten documents in grayscale or color.
Photographs (Prints)
| Image Types | Bit Depth | Color Space | Resolution (ppi) | Scale | File Format |
|---|---|---|---|---|---|
| B&W Photographs | 8-bit | Grayscale | 600ppi | 100% (1:1) | Tiff (uncompressed) |
| Color Photographs | 24-bit | RGB | 600ppi | 100% (1:1) | Tiff (uncompressed) |
- As of April, 2009, we scan both sides of a photograph even if one side is blank.
Photographs (Negatives and Slides)
| Image Types | Bit Depth | Color Space | Resolution (ppi) | Scale | File Format |
|---|---|---|---|---|---|
| B&W Negatives & Slides | 8-bit | Grayscale | 5000 pixels across the longest side* | 100% (1:1) | Tiff (uncompressed) |
| Color Negatives & Slides | 24-bit | RGB | 5000 pixels across the longest side* | 100% (1:1) | Tiff (uncompressed) |
- Not sure how to figure 5000 pixels across the longest side? Download a film sizes guide.
- For copy negatives, scan the entire negative. Do not crop to the original image. Do not crop out written notes.
Large Format (Posters and Maps) Above 17 x 24 inches (A2)
| Image Types | Bit Depth | Color Space | Resolution (ppi) | Scale | File Format |
|---|---|---|---|---|---|
| B&W Maps/Posters | 8-bit | Grayscale | 5000 - 10000 pixels across the longest side | 100% (1:1) | Tiff (uncompressed) |
| Color Maps/Posters | 24-bit | RGB | 5000 - 10000 pixels across the longest side | 100% (1:1) | Tiff (uncompressed) |
Newspapers
Newspapers should be scanned and digitally preserved in accordance with the national standards set by the Library of Congress for the National Digital Newspaper Program.
| Image Types | Bit Depth | Color Space | Resolution (dpi) | Scale | File Format |
|---|---|---|---|---|---|
| Microfilm | 8-bit | Grayscale | 400* | 100% (1:1) | Tiff 6.0 (uncompressed) |
| Physical Pages | 24-bit | RGB | 400 | 100% (1:1) | Tiff 6.0 (uncompressed) |
- Monitor equipment performance by capturing a standards-based target film strip or color image at the start of each scanning session.
- Split dual images into individual newspaper images as necessary.
- Deskew images with more than 3% skew.
- Crop page image files to the edge of the newspaper, retaining the original edge and up to a quarter inch beyond.
- Produce images that have exactly the same dimensions, spatial resolution, skew, and cropping as the images used for OCR.
*For microfilm, scan at 8-bit grayscale with a resolution of 400 dpi, if possible; otherwise between 300 and 400 dpi (relative to the size of the original newspaper).
Moving Image (Film and Video)
| Original Format | File Format | Codec | Audio | Resolution |
|---|---|---|---|---|
| 16 mm film | QuickTime (.mov) | Uncompressed YUV 10-bit 4:2:2 | 48 kHZ, 16-bit | Standard Definition (720x480) |
| VHS, SVHS, Betamax, Betacam, Umatic, DVCAM, DVC Pro, Mini DV, Laser Disc | QuickTime (.mov) | DV50 | 48 kHZ, 16-bit | Standard Definition (720x480) |
Audio
| Original Format | Bit Depth | Resolution | File Format |
|---|---|---|---|
| Cassette | 16-bit | 44.1 kHz |
Waveform Audio File Format (WAVE) .wav |
| Reel-to-Reel, Analog Disk | 24-bit | 48 kHz to 96 kHz |
Waveform Audio File Format (WAVE) .wav |
