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Greying Tests

Ballast soil for redeposition tests

“Soil makes a difference!” What is true for stain removal testing is even more true for assessing soil redeposition or rather: whiteness maintenance performance. Existing ballast soil systems with total soil quantities as for single wash tests may be used for such testing, but appear to require too many wash cycles to obtain significant results. An ideal redeposition test system replicates ‘real’ greying levels with less wash cycles: “Accelerate – don’t exaggerate!”

There is currently no commonly agreed test protocol for assessing whiteness maintenance… except the A.I.S.E. minimum test protocol which specifies the use of SBL2004 as soil ballast, dosed as for stain removal testing. However, the common experience (at least to our knowledge) is that the resulting soil level in the wash liquor is not sufficient for accelerated greying tests, the approach therefore of very limited suitability.

Whiteness Tracers

While Ballast soil is required to mimic redeposition, white fabrics are the tracers that are used to reflect and measure the effect. White test fabrics are available in some variety from different sources.

The A.I.S.E. minimum test protocol specifies the use of cotton, polycotton, polyester and nylon – which represents a common testing approach. However, we feel that ‘modern’ types of fabrics are very little represented so far but may add additional challenges to whiteness maintenance in practice.

Our MRF (market relevant fabrics) have been developed to open the option to also add whiteness tracers with optical brightener and some of them including fibre mixtures containing Elastane into the greying test program.