Focus variation technology as a tool for tissue surface characterization

Abstract The surface of tissue paper is relatively complex compared to other grades and consists several overlapping structures like protruding fibres, crepe fabric-based patterns at different spatial frequencies. knowledge characteristics crucial when it comes improvement with respect softness the perceptual handfeel products. In this work we used optical based, non-contact measurement principle focus variation for characterization dry-creped, textured through air dried (TAD) tissue. Based on three grades, a procedure which includes whole throughout scales within one setup, was developed. Surprisingly, rarely in tissue-related research, as provides robust reliable 3D information can be further areal analysis. Special attention given preparation discussion raw data up final analysis including filtering steps. Enhanced parameters developed interfacial area ratio (Sdr) power spectral density (PSD) were describe adequately. roughness compared, showing highest Sdr PSD Although both methods are based principles, high correlation terms evaluated evident. Regular obtainable peaks respective frequency certain intensity evaluation. Apart from topography roughness, wide field view also allows assessment effects related flocculation sheet formation. could appropriate fibre materials and/or fabrics, similar properties such example nonwovens. Graphic abstract