In order to maintain consistency in the quality of artifacts available in DigitalCommons@Linfield, we have developed the following guidelines to aid in content preparation. These guidelines explain the minimum requirements for digitization standards, as well as recommended and acceptable file types. Whenever possible, all newly acquired materials should adhere to these minimum requirements, although higher standards may be desirable for some materials. These guidelines are not intended to address all technical issues related to digitization.
Our standards are based on our need to balance the quality of the digital objects in DigitalCommons@Linfield with user accessibility. For that reason, we recommend two versions of digital files: one that is an archival quality master file, and one that is an access copy intended for web delivery. These standards represent our current needs and are subject to change, given the future needs of the repository and our users. If you need assistance converting your content from one file type to another, please contact the DigitalCommons Coordinator.
Any documents, whether typed or handwritten, that are not born-digital will need to be scanned. If full-text searching is desired, the document should be scanned and saved as a PDF using OCR (optical character recognition). If OCR is not desired, the document can be scanned and saved either as a PDF without applying OCR or as a JPEG. For handwritten documents, if OCR is used when creating the PDF, the text will likely be treated as an image (which means that full-text searching will not be possible). For best results, scan handwritten documents in grayscale or color rather than in black and white. If needed, backing paper may be used to enhance scan quality; refer to NARA's Technical Guidelines for Digitizing Archival Materials for Electronic Access (p. 42) for additional details, available at http://www.archives.gov/preservation/technical/guidelines.pdf.
| WEB DELIVERY | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
|---|---|---|---|---|---|---|
| Text (scanned) | PDF/A JPEG |
PDF RTF PNG |
JPEG: 640x480 to 800x600 PNG: 640x480 to 800x600 |
PDF/A: 300 pixels per inch JPEG: 72 pixels per inch |
PDF/A: minimal JPEG: medium |
8-bit grayscale (for black and white only) 24-bit color |
| Text (born digital) | PDF/A | PDF RTF |
||||
| ARCHIVAL MASTERS | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
| Text (scanned) | TIFF | none | 4000x2500 to 6000x4000 | 600 pixels per inch | lossless | 8-bit grayscale 24-bit color |
| Text (born digital) | XML+DTD (e.g., TEI) RTF ASCII/Unicode (TXT), using an editor that does not save to a proprietary format |
If the back side of the photograph contains markings or writing, scan both sides. Make sure that the file name clearly indicates whether a file is the front side or the back side. See File Naming in the Additional Considerations section below for additional information.
| WEB DELIVERY | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
|---|---|---|---|---|---|---|
| Photographs (prints) | JPEG | BMP GIF JPEG2000 PNG |
640x480 | 72 pixels per inch | JPEG: medium | 8-bit grayscale 24-bit color |
| ARCHIVAL MASTERS | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
| Photographs (prints) | TIFF | none | 4000x2500 to 6000x4000, excluding borders and mounts | 600 pixels per inch | lossless | 8-bit grayscale 24-bit color |
For more detailed information about specifications for digitizing transmissive originals (film, negatives, and slides), refer to the California Digital Library's Guidelines for Digital Objects, available at https://cdlib.org/wp-content/uploads/2021/06/cdl_gdo_v2021.pdf.
| WEB DELIVERY | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
|---|---|---|---|---|---|---|
| Photographs (negatives or slides) | JPEG | JPEG2000 | 800x600 | 150 pixels per inch | JPEG: medium | 8-bit grayscale 24-bit color |
| ARCHIVAL MASTERS | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
| Photographs (negatives or slides) | TIFF | none | 4000 pixels across the long dimension of the image area, excluding borders and mounts | 3200 pixels per inch | lossless | 8-bit grayscale 24-bit color |
Items larger than 17 by 24 inches should be digitized according to these specifications.
| WEB DELIVERY | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
|---|---|---|---|---|---|---|
| Large format posters or maps | JPEG | BMP GIF JPEG2000 PNG |
1078 pixels across the longest side | 150 pixels per inch | JPEG: medium | 8-bit grayscale 24-bit color |
| ARCHIVAL MASTERS | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimension (pixels) | Spatial (Capture) Resolution | Compression Level | Bit Depth |
| Large format posters or maps | TIFF | none | 6000-8000 pixels across the longest side | 600 pixels per inch (300-400 pixels per inch for larger items) | lossless | 8-bit grayscale 24-bit color |
Audio settings will vary based on the file type. To reduce file size further, you may use mono rather than stereo tracks.
| WEB DELIVERY | Recommended Format(s) | Other Acceptable Format(s) | Bit Depth | Sample Rate |
|---|---|---|---|---|
| Audio (voice) | MP3 | AIFF M4A WAV WMA |
28-128 Kbps | 11 KHz |
| Audio (music) | MP3 | AIFF M4A WAV WMA |
128-224 Kbps | 22-44.1 KHz |
| ARCHIVAL MASTERS | Recommended Format(s) | Other Acceptable Format(s) | Bit Depth | Sample Rate |
| Audio (voice) | AIFF WAV |
none | 8-16-bit mono | 22 KHz |
| Audio (music) | AIFF WAV |
none | 16-24-bit stereo | 44.1-48 KHz |
Pixel size should generally be kept between 160x120 and 320x240, although higher sizes are acceptable (640x480 to720x480).
| WEB DELIVERY | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimensions (pixels) |
|---|---|---|---|
| Video | H.264 | MOV MPEG-1 MPEG-4 |
160x120 to 320x240 |
| ARCHIVAL MASTERS | Recommended Format(s) | Other Acceptable Format(s) | Spatial Dimensions (pixels) |
| Video | raw video file MPEG-2 DVD-quality video file |
none | 720x480 or higher |
Image Adjustment: Images should be rotated as needed post-scanning for ease of viewing. Depending on the project, cropping, color and contrast adjustments, sharpening, and other post-scanning adjustments may also be necessary. The Nicholson Library's computer lab has software for digital image editing.
Watermarks: Visible watermarks are not recommended for archival masters or web delivery access copies. We recommend using electronic or "invisible" watermarks to provide proprietary rights information as an alternative means to protect digital intellectual property. Rights information can also be provided through administrative metadata as part of an item's record (refer to the rights section of the Metadata Standards for DigitalCommons@Linfield).
File Naming: File names should be unique, consistently structured, and should use numbers and/or lowercase letters. Use underscores rather than spaces in file names, or use CamelCase. Do not use symbols in file names. If using a numerical scheme, use leading zeros for ease of sorting, and take into account the maximum number of items to be scanned so that you use an appropriate number of digits.
Examples:
MeAndMyMexican-AmericanCulture_Escalera_2013.jpg
SunsetOnTheMekong_Taie_Judges_2.jpg
AraguzDecemberCazarPublishedVersion2016.pdf
Version 3.0 (current) prepared by Kathleen Spring (DigitalCommons Coordinator), January 11, 2019.
Version 2.0 prepared by Kathleen Spring (DigitalCommons Coordinator), November 26, 2013.
Version 1.0 prepared by Kathleen Spring (DigitalCommons Coordinator), January 5, 2011.