A.D.I.E.M ©
Bob DiNatale
Scan Test to Optimizing Your System
This test will determine the optimum input/output of your system (scanner and printer) as YOU see it. This test works for both print and film scanners. Simply put, you will do a series of scans at various scan rates and then print each scan through Photoshop. You will then view them to empirically determine your system optimization.
*Just a note... sometime it's may be helpful to have others chose "the best" print from the series. While working on new films and emulsions at Polaroid, it was interesting to observe how "the best" result was chosen. The prints were posted by the cafeteria and as the employees walked by they would chose "their best" print. The reasoning was that the employees were more typical viewers and the results would not be effected by the scientist's bias.
Doing your test ...
For this test you will need Photoshop to print the test and a scanning software with the ability to enter scan resolution and scaling settings. You will make a total of 8 scans. I use a Kodak Q-60 Color Input Target, shown above, as a scan sample. (Target is available in both paper and film material.)
1 - Select a typical sample to scan. (I use a Kodak Q-60 Color Input Target)
2 - Set scan resolution to 100ppi and scaling at 100%
3 - Select an area with the "bounding box" (or enter input values) width = 5" and height = 4" then scan
4 - Without changing the bounding box, change the scan resolution to 125 ppi then scan again.
  [repeat Step 4 with scan resolutions of 150; 175; 200; 250; 300; 350 ppi]
5 - Save each file as 100ppi; 125ppi; etc.
6 - Use Photoshop and print each file. Write PPI on back of prints!
  ...you'll need 8 - 4x6 sheets or 8 - 4x5.5in (1/4 of an 8.5x11) paper
7 - Mark and view prints* to choose the optimum scan/print resolution.
[Repeat with other printers / scanners combinations you may have]
Revision 2.3

Scan Test (Advanced)
I usually scan my image and do my adjusting in Photoshop with two exceptions:
  1) when scanning a half tone printed image, I will use a "descreen" filter at point of scanning. This is better than the "Despeckle filter in Photoshop.
2) adjust exposure and contrast to optimize the data being converted to digital information.
(see calibrating scanner below)
Calibrating Your Flatbed Scanner with Gray Card...
Because exposure is as important to the acquisition process (converting analog to digital) as snapping the shutter (putting the light on film) it is important to check your scanner for proper exposure. I do this by scanning a gray card and view the resulting histogram in Photoshop. The histogram should display a dispersion of pixels at or near the 128 value. Using a gray step wedge will also allow calibration for contrast.
A good software allows adjustment for brightness and contrast during scanning. If your software allows for such adjustment you can easily calibrate your scanner.
1. Place a gray card in the flatbed scanner.
2. Select an area and scan in RGB color mode
3. View the resulting scan in Photoshop for exposure:
  - Menu:>Image>Adjust>Histogram
4. View the resulting scan in Photoshop for color balance:
  - set the "Eyedropper" tool to 5x5 pixels
- make the "Info" palette visible change the color options to RGB and HSB
- move the eyedropper anywhere on the gray scan and view the values... the should be near 128 in ALL "RGB" values; a Brightness near 50% and and a Saturation near 0 in the HSB
If the values vary dramatically from above, change the exposure and color setting in the scanner software before scanning.
Revision 1.0