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Evaluation of the in-homogeneity of toner based printing systems

Aim:

To have a objective metric for testing lack of homogeneity both for toner based and inkjet systems.

Current Activities:

To improve the M-score metric by scanning the Homo test charts  and perform the analysis on a higher spatial resolution (compared to the 6x6 mm of the iSis)

Required test forms:

Currently we are looking for print outs of our homo test forms which are made on (LFP and production) inkjet devices. Homo test forms

What is M-Score?

What does it mean?

M-ScoreMeaningExample
≥ 95PerfectInkjetprint on proofing substrate showing no visible inhomogeneities
≥ 80Very goodPrint with slightly visible inhomogeneities (e.g. some Mottling). No visible stripes.
≥ 70GoodPrint with visible inhomogeneities (Mottling) but almost no visible stripes.
≥ 60SatisfactoryMottling and stripes visible. Is still accepted by most observers.
≥ 50AdequatePrint with clearly visible mottling and/or stripes. Acceptance is highly dependent on the printed image.
< 50PoorClearly visible mottling and stripes. Not accepted as high quality print

 

How to evaluate it [for each tint value - recommended are the three composed grey ones]

1. Print pertinent Fogra digital print quality testforms [use either the A3 or the two A4 test formes]
2. Measure the charts (e.g. with the iSis and ColorPort)

 

2011_ColorPort_HomoA4_1_2_3.zip11,5 KB2011
2011_ColorPort_HomoA3_1_2_3.xml314 KB2011

 

Matlab Implementation

Matlab Publish Code

Revised Code (including the omission of the samples at the border)

A4-Sample Measeurment



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