Influence of hardwood, softwoodand fractionated pulp in a stratifiedthree-layered fine paper : Lövved, barrved och fraktionerad massa ochdess inverkan på ett treskiktat finpapper

Four different trials of stratified three-layered fine paper, of sulphate pulp, were performed to investigate if stratified fine fraction or fibres from birch can improve the properties of a paper compared to a reference sheet. All trials had five different scenarios and each scenario was calendered with different linear load. All sheets had a grammage of 80 g/m2.In the first trial, the paper contained birch, pine and filler of calciumcarbonate (marble), and was manufactured with the pilot paper machine XPM and the stratified headbox Formator at RCF (Stora Enso Research Center in Falun). The furnish consisted of 75% birch and 25% pine.The second trial contained coated sheets with paper from trial one as the base paper. The coating slip contained calciumcarbonate and clay and the amount was approximately 10-12 g/m2.The third trial, also with birch and pine but without filler, was performed at STFI (Skogsindustrins Tekniska Forskningsinstitut in Stockholm) with the laboratory scaled paper machine StratEx and the stratified headbox AQ-vanes. The furnish consisted of 75% birch and 25% pine, except for one scenario which contained of 75% pine and 25% birch.The last trial contained fractionated pulp of birch and pine and was performed at STFI. 50% was fine fraction and 50% was coarse fraction.This test does not show any clear benefits of making stratified sheets of birch and pine when it comes to properties such as bending stiffness, tensile index and surface smoothness. The retention can be improved with birch in the surface plies. It is possible that the formation can be improved with birch in the surface plies and pine in the middle ply. It is also possible that fine fraction in the surface plies and coarse fraction in the middle ply can improve both surface smoothness and bending stiffness. The results in this test are shown with confidence intervals which points out the difficulties of analysing sheets manufactured with a pilot paper machine or a laboratory scaled paper machine.

ICC-profilers användbarhetvid gråbalansjusteringav arkoffsettryck

I detta examensarbete har gråbalansstyrning och ICC-profilers duglighet undersökts. ICC-profilernahar utvärderats utifrån den tryckkvalitet de genererat tillsammans med olika papper.Gråbalansstyrning har använts som gemensamma likare för samtliga testtryckningar. Detta tillfördeen variabel som var lika för samtliga papper i utredningen. Här med ökade sannolikheten att ICCprofilerskapade från olika papper, skulle ge en likvärdig kvalitet.I arbetet har många mätningar och beräkningar genomförts. De två främsta anledningarna till dettavar dels att utreda i vilken mån det gick att gråbalansjustera trycket och dels att inhämta jämförbaravärden på likheter och divergenser mellan olika kombinationer av ICC-profiler och papper. Mätdatahjälpte även till att ta hänsyn till de felkällor som fanns.Det var möjligt att gråbalansjustera trycket och det fanns likheter mellan en ICC-profil på olika papperoch även mellan fler ICC-profiler på samma papper. Samtliga resultat och slutsatser var beroendeav att neutral gråbalans upprätthölls under tryckningarna. Subjektiva och objektiva jämförelser visadebåda på att en ICC-profil inte kommer att påverkas av variationer mellan olika pappersleveranser,såvida dessa inte är större än skillnaden mellan de olika papperna.Med säkerhet kunde inte förutsägas från vilket papper en ICC-profil skulle skapas för att ge en högkvalitet på flera papper. Mest troligt var att likvärdigt resultat skulle kunna uppnås på G-Print, MultiArt Matt och Multi Art Silk.

ICC-profilers duglighet vid gråbalansjustering av arkoffsettryck

Adjustment to a neutral colour balance when printing was the starting point in this degree project. Onthis base ICC-profiles were evaluated and assessed. The survey was concentrated on the similarity betweenreproductions on different papers with various ICC-profiles. The colour balancing introduced aconsistent variable between four graphic papers. With raised uniformity the probability increased toreceive similarities between the various combinations of ICC-profiles and papers.Numerous of measurements and calculations have been carried out, mainly to confirm whether or notadjustment to a neutral colour balance is possible and repeatable. Further more this gained in comparablevalues corresponding to similarities and divergences between combinations of ICC-profiles andpaper.The research concluded in the fact that it was possible to reach a neutral colour balance. One ICCprofileused together with various papers and also one paper with several ICC-profiles resulted in similaritiesand formed groups of samples. Since equivalent results could be reached on different samples,it implicated that variations within one paper shouldn’t affect the ICC-profiles. This was valid when thevariations were less than the divergence between the papers.Certain predictions on the question of from which paper the ICC-profiles should be generated to createhighest quality in print hasn’t been able to assemble. It’s likely that equivalent results could begenerated on G-Print, Multi Art Matt and Multi Art Silk.