Minimum standards for automated fitness checking of euro banknotes by banknote handling machines
In the course of the fitness checks, euro banknotes with any defect in respect of which a mandatory requirement has been defined as set out below are unfit.
The acceptable tolerance level for the fitness checks by banknote handling machines is 5%. This means that a maximum of 5% of the euro banknotes that do not meet the fitness criteria may be misclassified by the machines and sorted as fit.
|TABLE 1: LIST OF SORTING CRITERIA FOR AUTOMATED FITNESS SORTING
|General distribution of dirt across the entire euro banknote
|Localised concentration of dirt
|Added image or lettering written or marked in any manner on a euro banknote
|Lack of ink on part or whole of the euro banknote, e.g. a washed euro banknote
|Euro banknotes with part(s) missing, along at least one edge (in contrast to holes)
|Parts of one or more euro banknotes joined together by tape or glue or other means
|Multiple random folds
|Structural deterioration resulting in a marked lack of stiffness
Further information on sorting criteria
Soil increases the optical density of euro banknotes. The following table specifies the maximum density increase of limit samples compared to new euro banknotes that euro banknotes may exhibit to be classified as fit:
|TABLE 2: OPTICAL DENSITY LEVELS
|Maximum density increase of limit sample compared to new euro banknote
Euro banknotes not meeting these criteria are unfit. National central banks (NCBs) keep reference euro banknotes showing a soil level derived from these criteria. The densitometric measurements of the reference euro banknotes are based on the following criteria.
- Standard for density measurements: ISO 5 parts 3 and 4
- Standard for the filters: DIN 16536
- Absolute measurements: standard calibration (white tile)
- Polarisation filter: on
- Aperture: 3 mm
- Illumination: D65/2
- Background: white tile standard calibration
The density increase of a reference banknote is the highest value between the averages of at least four measurement points measured on the front and on the back of the banknote in the unprinted area and without any watermark modulation.
Euro banknotes with a localised concentration of dirt covering at least 9mm by 9mm in the non printed area or at least 15mm by 15mm in the printed area are unfit.
At present there is no mandatory requirement to detect graffiti.
De-inking of euro banknotes can occur, e.g. if they have been washed or subjected to aggressive chemical agents. These kinds of unfit euro banknotes might be detected by image detectors or UV detectors.
Euro banknotes with tears which are open and not partly or fully covered by the machine’s transport belt(s) are unfit if the size of the tear is greater than indicated below.
|TABLE 3: TEAR
Euro banknotes with holes which are not partly or fully covered by the machine’s transport belt(s) are unfit if the area of the hole is greater than 10 mm2.
Euro banknotes with lengths reduced by 6mm or more or widths reduced by 5mm or more are unfit. All measurements relate to differences from the nominal lengths and widths of the euro banknotes.
A repaired euro banknote is created by joining parts of euro banknote(s) together, e.g. by using tape or glue. A euro banknote with tape covering an area greater than 10mm by 40mm and which is more than 50µm thick is unfit.
Crumpled euro banknotes can normally be identified if their level of reflectance or stiffness is reduced. There is no mandatory requirement.
As far as possible, euro banknotes with very little stiffness are sorted as unfit. As limpness normally correlates with soiling, limp euro banknotes are generally also detected via soil sensors. There is no mandatory requirement.
Folded euro banknotes, because of their reduced length or width, can be detected by sensors checking the size of the euro banknotes. In addition, they can be detected by thickness sensors. However, due to technical limitations, only folds fulfilling the criteria laid down for mutilations, i.e. folds leading to a reduction in length greater than 6 mm or a reduction in width greater than 5 mm, can be identified and are unfit.
A euro banknote with a folded corner with an area of more than 130mm2 and a length of the smaller edge greater than 10mm is unfit.
1 This is measured by drawing a straight line from the peak of the tear to the edge of the banknote where the tear begins (rectangular projection), rather than measuring the length of the tear itself.