### Needed  
ImageJ (from http://rsb.info.nih.gov/ij/)  
Working scanner (can be hard)  
### Scanner Settings   
Set to Grayscale.  
Set to 600 ppi.  
Set to wtb points.  
Set to Custom ~130,255.  
Set Preferences -> Scan Material -> Positive.  
Set Preferences -> More -> Scan Quality -> Quality.  
Set Preferences -> More -> Interpolation -> Speed.  

### Image J  
Go to Analyze -> Set Scale.  
Over there change:  
Distance in Pixels -> 600  
Known Distance -> 25.4  
Pixel Aspect Ratio -> 1  
Unit of Length -> mm