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AgentZ - World Wide Agents
Scan Resolution Differences
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This is the target image. The image was scanned 2 times at 72 and 300 ppi. The 300 ppi image was reduced in Picture Publisher to 72 ppi.
This image was scanned at 300ppi and reduced in Picture Publisher to 72ppi
This image was scanned at 72ppi. While they appear identical there are a few subtle differences.
This image is the same image as the target image. It has been reduced by using the height and width tags in the HTML code. While it looks great, right click on it and compare its size one of the images above.

Check out the differences below.


    

This is from the reduced image. Notice not only the overall softness of the image but notice that the highlights in the eyes are almost completely gone. This was from the 72 ppi scan. Notice the overall image is slightly sharper and the highlights are clearly visible in the eyes. This is from the reduced image. Notice almost all the detail in the teeth was retained. This was from the 72 ppi scan. Notice that when scanned at this resolution the scanner picked up practically no detail in the teeth.



What does this prove? While the overall image quality of the 300 to 72 image appears better and can be improved by using an unsharp filter the subtle highlights in the eyes are lost. The resolution you scan at will depend on what you are imaging and how much detail and highlight you need. Only experimentation on your actual images will determine what is best for each item.

Here is the process so you can see which is more efficient on your equipment and with your photo editor.

  1. take your photo.
  2. scan at 72 ppi - save as image_72.bmp
    1. (or use whatever the default format your scanner saves in)
  3. scan at 300 ppi - save as image_300.bmp
  4. open the image_300.bmp in your image editor
  5. open the image_72.bmp in your image editor
  6. reduce the resolution of image_300.bmp to 72ppi
  7. use your image editors magnifying glass to examine details
  8. You decide which algorithm works best

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