Digitizing Still Images for GloPAD
A. Introduction
Two files are needed when uploading a still image (photograph, slide, text) to the database: digital object and thumbnail. An additional file is recommended for the owner's archives.
These instructions explain how to digitize photographs using Adobe Photoshop, without reference to any specific scanner. You may need to ask for instructions on how to operate the scanner you are using.
Slides:
We have not yet developed specific instructions for scanning slides. Scanning a slide is more complex than scanning a photograph because of the light that needs to come through the slide. If you have slides of images you wish to include in the database but do not have experience scanning slides, please contact Susan Specter, GloPAC Managing Editor and Trainer, sps19@cornell.edu, before beginning to scan.
B. Scanner Specifications
Please read this section to determine whether you are using a scanner with acceptable resolution.
Do not use a scanner with optical resolution under 600 dpi (dots per inch).
It is best to use one with optical resolution of 1200 dpi or higher.
There are two types of resolution: optical and interpolated. The optical resolution is the highest resolution that the scanner can actually scan at. For interpolated resolution, software is used to fill in more dots to make it look like the resolution is higher, but it is just guessing at what colors the extra dots should be. For archival files, we want to make sure that we are only scanning at the optical resolution—not the interpolated resolution—because we only want the "real" digital information, not something the software guesses at and adds in.
You need to look in the documentation that came with your scanner, or look up its specifications on the Web, to determine its optical resolution. If the documentation says something like, "true optical resolution of 1200 dpi" and "maximum resolution of 9600 x 9600 dpi with interpolation," you know for sure that the optical resolution of the scanner is 1200 dpi. However, not all scanners will state the optical resolution as clearly as this. They might only give one number, and not state whether it is optical or interpolated, in which case there is no way to tell which it actually is. If that is the case, you just have to use the number they give as if it is the optical resolution.
Please note: you cannot determine the optical resolution by what the software allows you to scan at. For example, it might let you enter 1200 dpi, or have that number on a drop-down list, but that could be either optical or interpolated resolution. If the documentation states that the scanner's optical resolution is 600 dpi, but the software lets you scan at 1200 dpi, then you know that the 1200 dpi (or anything higher than 600) is interpolated. In this example, you should scan the image at 600 dpi.
If you do not have access to the documentation that came with the scanner you are using, or if you cannot find its specifications on the Web, please send an email to Susan Specter, GloPAC Managing Editor and Trainer, sps19@cornell.edu, with the scanner's brand and model number.
C. Organizing the Image Files
To keep the image files organized on your computer or disk, it is helpful to create one folder, named Images, that contains three folders, named:
1. Archive
2. Digital Object
3. Thumbnail
Name your files according to your institution’s file-naming convention, if it has one. Otherwise, follow GloPAD guidelines for naming digital object files, included in a separate attachment, named GloPAD_file_naming_guidelines.doc.
Keep the same file name for each file. As you create each file, save it in the appropriate folder.
Example:
First, you create the archival file. You name it KWBatsumo0001 and save it in the Archive folder. You then create the digital object file, keeping the same file name (KWBatsumo0001) and saving it in the Digital Object folder. Last, you create the thumbnail file, still keeping the same file name (KWBatsumo0001) and saving it in the Thumbnail folder.
D. Creating the Archival Copy
This is for the owner's archives only; this file does not get uploaded to the database. We recommend using the specifications outlined in these instructions. If scanning for GloPAC-owned archives, these specifications are required.
Specifications:
Resolution of scanner: optical resolution of at least 600 dpi, 1200 dpi preferred (see Scanner Specifications, above).
Resolution of image:
Color photograph: 1200 dpi or the optical resolution of the scanner, whichever is lower (Cornell University Library recommends 600 dpi, but we prefer to use 1200 dpi if the scanner's optical resolution is that high.)
Slide: 2200 dpi or the optical resolution of the scanner, whichever is lower. (Scanning slides is more complex because of the light that needs to come through the slide. If you have a slide collection, please contact Susan Specter, GloPAC Managing Editor and Trainer, sps19@cornell.edu, before beginning to scan.)
File format: TIFF
Instructions:
1. Open Adobe Photoshop.
2. From the File menu, select Import.
3. Select Twain 32, or whatever Twain driver your software uses.
4. A preview of the image will appear in the scanning window. A rectangular box that you can resize will appear around the image. The box will probably be lined up with the edges of the image. To scan only a section of the image, resize the box as desired. Do not worry about sizing it exactly; you can crop the image further in Photoshop, after it has been scanned.
5. Select a resolution of 1200 dpi, or the optical resolution of the scanner, whichever is lower. (Cornell University Library recommends 600 dpi, but we prefer to use 1200 dpi if the scanner's optical resolution is that high. See Scanner Specifications, above)
6. Click on the Scan button.
7. Once the scan is complete, the image will appear as a file in Photoshop. You may have to close the scanning window.
8. Crop and otherwise edit the image if necessary.
9. From the File menu, select Save As.
a. Select your Archive folder (see Organizing the Image Files, above).
b. Name the file.
c. Select TIFF as the file type.
d. Click the Save button.
10. Proceed to instructions in Creating the Digital Object File, next.
E. Creating the Digital Object File
The digital object file will be uploaded to the database. The following specifications are required.
Specifications:
Height: 700 pixels
Resolution: 300 dpi
File format: JPEG
JPEG quality: medium
Instructions:
1. In Adobe Photoshop, open your archival file. (This file will still be open if you are continuing from the previous section, Creating the Archival Copy.)
2. From the Image menu, choose Image Size.
a. Make sure Constrain Proportions is selected.
b. Change the resolution to 300 dpi.
c. Change the height to 700 pixels (make sure the height is in pixels; you might have to choose pixels from a drop-down list). Because you constrained the proportions, Photoshop will automatically adjust the width.
3. From the File menu, select Save As.
a. Select your Digital Object folder (see Organizing the Image Files, above).
b. Do not change the file name.
c. Select JPEG as the file type.
d. Click on the Save button.
e. When JPEG Options appears, choose medium quality.
4. Proceed to instructions in Creating the Thumbnail File, next.
F. Creating the Thumbnail File
The thumbnail file will be uploaded to the database. The following specifications are required.
Specifications:
Height: 125 pixels
Resolution: 150 dpi
File format: JPEG
JPEG quality: medium
Instructions:
In Adobe Photoshop, open your digital object JPEG file. (This file will still be open if you are continuing from the previous section, Creating the Digital Object File.)
1. From the Image menu, choose Image Size.
a. Make sure Constrain Proportions is selected.
b. Change the resolution to 150 dpi.
c. Change the height to 125 pixels (make sure the height is in pixels; you might have to choose pixels from a drop-down list). Because you constrained the proportions, Photoshop will automatically adjust the width.
2. From the File menu, select Save As.
a. Select your Thumbnail folder (see Organizing the Image Files, above).
b. Do not change the file name.
c. Select JPEG as the file type.
d. Click on the Save button.
3. When JPEG Options appears, choose medium quality.