[Printers] obfuscate dots?

[Rein]

dear yellowdots_finders!

I'm relatively new to this subject. I write about about postage stamps and  
their printing technics and I am preparing an article about the Austrian  
personalised stamps. Examining them I found clouds of yellow dots printed  
on them and I just thought it was a security device made by the Austrian  
State Printing Works. Then two weeks ago an article appeared in the Michel  
Rundschau saying that similar dots were found on the Spanish personalised  
postage stamps. The State Printer in Vienna has disclosed than that the  
dots are made by their Xerox DocuColor and that it reveals the machine  
identification code plus a time+date indication.

Having gathered lots of these stamps I found out that the MICs were there  
 from the beginning i.e. late 2003 and finding your articles on www.eff.org  
I started to look out for similar prints on other personalised stamps.

I haven't found any on Belgian ones yet [since 2001] but did find  them on  
the Dutch personalised stamps from the very beginning in mid 2003! All  
Dutch items had been printed on 4 Ricoh Aficio CL5000 till late 2005.

Other than mentioned in the EFF article, the matrix is 8x7 (apart from the  
2 dots at the top right) and not 15x8.

http://www.xs4all.nl/~dziewon/fila/various/waz_docu2   (Austria, late 2003)

http://www.xs4all.nl/~dziewon/fila/various/ricoh_cl5000 (Netherlands, mid  
2003)

The scans I made are with HP PrecisionScanPro using a 1200 dpi resolution  
and getting predominantly yellow.

http://www.xs4all.nl/~dziewon/fila/various/HP_scan

I continue examining the personalised as they also have a more or less  
known date of issue [and of use as indicated by cancellations.

groetjes, Rein



On Mon, 16 Apr 2007 02:55:48 +0200, Seth David Schoen <schoen at eff.org>  
wrote:

>

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