Frequently Asked Questions about Digitizing Materials for Ohio Memory
If your institution chooses to scan their own materials for the Ohio Memory Project, please review these answers to frequently-asked questions.
May I scan the materials that are accepted at our institution?
Yes, as long as your equipment can produce images at the required standards. All accepted materials must be scanned as high-resolution uncompressed TIFFs. These high-quality TIFFs will be used to generate smaller, faster-loading access images that will be viewed by those using the scrapbook. See Scanning Specifications for Digital Projects/Preservation for further information.
May I send one image as a sample before I scan them all?
Yes. We strongly encourage institutions that are scanning large quantities of materials to send a sample or two to ensure that the scanning specifications are correct before going forward.
How do I send you the images (e-mail, CD, etc)?
You may send images in whatever format you prefer. However, many email systems block large attachments, so many prefer to send images on CDs, DVDs, flash drive or external hard drives. We also have the ability to receive via FTP if your institution has that capability.
If we provide TIFFs, can’t someone download our image and publish it without permission?
Searchers will not view the TIFFs, but rather the derivative access images, which are not of sufficient quality for publication.
Why does the DPI have to be so high?
The project’s scanning philosophy is to cause as little wear to the original as possible. Therefore, it is desirable to scan the materials only once, which requires that the images be suitable for a range of uses. Although low-resolution images are acceptable for viewing at original size on a computer monitor, they are not good enough for viewing image detail or for publication.
What is the difference between a preservation image and an access image?
A preservation image is a very high resolution image that is best suited for archival preservation or print publications. These file formats do not incur a loss of data or image quality, while preserving more colors and details found in the original item. The most common file type for a preservation image is TIFF (Tagged Image File Format). An access image is a smaller file (in terms of the amount of space required to store it and time required to download it) that is best suited for publishing on the web. These formats compress the image, and can affect the quality of the resulting image. The most common file types for access images are JPEG, JPEG2000 and PNG.
Why can’t I send a high-quality JPEG?
Even high-quality (low-compression) JPEGs involve unrecoverable information loss and are almost always unacceptable to publishers as an image format. Scanning an image as a TIFF ensures maximum flexibility and usability for the future.
May we scan items as JPEGs and then save them as TIFFs?
No. Once an item is scanned as a JPEG, the loss of information is immediate and permanent. Resaving the image as a TIFF does not undo the loss of quality.
May I change the DPI after an item has been scanned?
Increasing the resolution of an image after it has been scanned should not be used as a way of meeting the standard. Image editors use “interpolation,” an artificial means of inserting pixels, to increase resolution. Only scanning at the correct resolution will ensure proper image quality.
I have an image that was scanned by someone else. How do I determine the resolution?
Various editing programs allow you to determine resolution. For example, in Adobe Photoshop, you can select the “Image size” option to see the pixel dimensions and resolution. If you are unsure about your own software, please contact project staff.
How do I set the resolution on the scanner?
Most scanners come with some sort of scanning software, and all of them vary in terms of how they set resolution. When you bring up that software, look for an option for selecting DPI or PPI (Pixels Per Inch), and enter or select an appropriate PPI (see Scanning Specifications for Digital Projects/Preservation).
I want to take photographs with my digital camera. How do I ensure preservation quality images?
Some high-end digital cameras take TIFF images, but many only take RAW. Your camera’s instruction manual should tell you. Either of these formats can be submitted, but please feel free to contact project staff if you are unsure.
What if my document is too large for the scanner?
On occasion larger items scan be scanned in separate pieces and then “stitched” back together. However, this is very time-consuming and requires very high-resolution images. Because image quality lessens substantially each time changes are made by an image editing program such as Photoshop, this procedure is discouraged. Exceptions may be made on a case-by-case basis. OHS Digital Services Department provides scanning services for large format items. Please contact firstname.lastname@example.org for information.