Tardigrade Assignment
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How to scan lichens to determine surface area.

  1. Turn on computer and scanner
  2. Run Adobe PhotoShop.  When program boots up, pull down FILE menu and open IMPORT command.  Click on FotoLook
  3. When FotoLook extension runs you will see a large dialogue box.  Set the scan resolution to 72 ppi and grayscale.  Click on PREVIEW and wait for scanner to do a preview.  Set the limits on the preview to match the size of your lichen.
  4. Click on scan and scan your lichen.  When done scanning, image of lichen will appear in Photoshop window.  Save that image as a jpeg image.  When you pull down the FILE/SAVE menu you will see JPEG as one of the file types you can save images as.   Use the defaults. Save your image in your invertebrate folder on OZ. Your image must be only one plane and either grayscale or color to do this. 
  5. Close PhotoShop and open NIH Image.
  6. Measure a horizontal distance for the lichen on your Xeroxed page with a centimeter ruler. 
  7. In NIH IMAGE open your previously saved JPEG file.  You should find that file in your invert. folder on OZ.  Measure the same horizontal distance you measured above, only this time in pixels (pixels will be recorded in small window at bottom left).   After opening image,  go to the menu that allows you to set scale.  On the SET SCALE Dialogue box, click units of measure as "cm" .  Fill in boxes for pixel measurements and actual measurements.  Anything you measure on the image will now be measured in cm. 
  8. Go to menu that allows you to density slice the image and click on density slicing.   The density slice tool has arrows at top and bottom.  Use it to spread the red up or down in the "LUT" window (this is the tall window with the color gradient).  You may have to erase extraneous material around the lichen to allow you to get the lichen to turn totally red.  Don't worry if every single pixel is not red.  
  9. When most of lichen is red, use menu that has the measure command.  Click on measure.  Area will appear in small box at bottom left.  Record this for the exercise.  Remember to do a back of the envelope calculation to check out the computer measurement for area.
  10. Close program and shut down computer and scanner.  Please always turn the scanner off when done so as to not burn out the scanner bulb.