2019.2

Contamination
The single but critical danger with any implementation that deals with PlanetPress Capture is
"Contamination". Basically, contamination happens when an Anoto Digital Pen writes on a
"wrong" document or is docked in the wrong location. This can happen any number of ways
and in different situations, and can have devastating effects in some of those cases so please
pay special attention to this section.
First, contamination is not limited to implementations that extend their patterns through
methods 1) and 2) above. Any time that a pen writes on a "wrong" document, it is considered
contamination. A simple example in a basic implementation would be to print a document with
a pattern on it, put this paper aside (or lose it on a desk somewhere) and forget about it.
Assuming proper processes were put in place, this document would eventually be closed by a
manual or automatic procedure. However, the physical document with the pattern still exists
even if it is closed in regards to the PlanetPress Capture database. Contamination would
happen if a new document is printed with the same pattern, but somehow the "old" document
re-surfaces and someone writes ink on it and docks the pen. When this happens, neither the
pen nor PlanetPress Workflow can understand that the data does not belong on that document
and will happily update the "current" document, possibly closing it. Because the "old" document
relates (presumably) to a different client, this means the "current" document has invalid
information.
This can be prevented through simple methods such as printing a date on each sheet and
ensuring that users never sign a document that is older than a certain time, for example 48
hours. These sheets should simply be destroyed.
Second, contamination can happen in method 1) above if a pen or paper is moved from one
location to another. Similarly to the previous contamination example, if there exists a document
in the Capture Database where the "wrong" data is processed, it will update a document where
it does not belong. Again, neither the pen nor PlanetPress Workflow have any idea that this
causes an error until it's too late.
Third, contamination (the most common one) can happen if pattern sequences get mixed up, if
pens or paper gets swapped between users, etc. For example, again using a shipping
company (with example 2-A), if two of the drivers were to meet for a coffee and exchange their
pens inadvertently (we hope, anyways), the pens would be signing the "wrong" documents all
day and, when docked, would update the wrong documents in the database.
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