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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?
May I send one image as a sample before I scan them all?
How do I send you the images (e-mail, CD, etc)?
If we provide TIFFs, can't someone download our image and publish it without permission?
Why does the dpi have to be so high?
What is the difference between a TIFF and a JPEG?
Why can't I send a high-quality JPEG?
May we scan items as JPEGs and then save them as TIFFs?
May I change the dpi after an item has been scanned?
I have an image that was scanned by someone else. How do I determine the resolution?
How do I set the resolution on the scanner?
I want to take photographs with my digital camera. How do I tell if it takes TIFFs?
What if my document is too large for the scanner?
General 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 TIFFs. These high-quality TIFFs will be used to generate smaller, faster-loading JPEG images that will be viewed by those using the scrapbook.
- Photographs must be scanned as TIFFs at 300 dpi minimum.
- Handwritten documents must be scanned at 400 dpi minimum and saved as TIFFs.
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 CD or zip disk. Also, since images are scanned as high-resolution TIFFs, they are usually too large to fit on floppy disk. 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 JPEG images, which are not of sufficient quality for publication.
File Formats and Resolution
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 creating smaller or larger sizes (thumbnails or magnified images), or for publication.
What is the difference between a TIFF and a JPEG?
A TIFF is a very high resolution image that is best suited for archival preservation or print publications. Also, a TIFF is an uncompressed image. Compressing a file results in a loss of data and image quality. A TIFF image preserves more colors and details found in the original item. A JPEG is a smaller file (in terms of the amount of memory required to store it and time required to download) that is best suited for publishing on the web, since most monitors can display only 72 dpi. A JPEG compresses the resolution of an image, and so will appear grainy or pixilated when printed or magnified by zooming in.
Why can't I send a high-quality JPEG?
All images are stored in OhioLINK's Digital Media Center, which requires all items be submitted as TIFFs. These TIFFS are then used to generate smaller, faster-loading files.
May we scan items as JPEGs and then save them as TIFFs?
No. If an item is scanned as a JPEG, it does not have all the information or quality that a TIFF does. Saving the image as a TIFF merely changes the file extension, it does not improve the image quality.
May I change the dpi after an item has been scanned?
You cannot increase the quality or dpi of an item once it is scanned. Attempting to do so causes the photo-editing software to "interpolate," or add pixels, to the image. This causes the unattractive pixilated images one often sees on websites.
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.
Scanners and Digital Cameras
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, which might also be labeled ppi or lpi, and enter or select at least 300. Your scanning software also might allow you to specify image resolution or image quality. Usually, the choices will be good, better, or best quality or possibly low, medium, or high quality. Select whatever is the highest quality.
I want to take photographs with my digital camera. How do I tell if it takes TIFFs?
Some high-end digital cameras do take TIFF images, but many only take JPEGs. Your camera's instruction manual should tell you. 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 can 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.
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