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Ink–paper interaction is a key aspect of inkjet printing and directly determines print quality, dimensional stability, and long-term performance. When a multicomponent ink droplet is deposited on cellulose-based paper, spreading, capillary uptake, pore–fiber transport, and fiber swelling unfold in rapid succession. These processes are heavily influenced by the interaction between the substrate’s material properties and the behavior of the ink components. Co-solvents and surfactants are particularly important: co-solvents become the dominant liquid component in the paper once water evaporates and strongly affect transport rates, swelling, and residual deformation, while surfactants govern wetting and interfacial dynamics. Yet the mechanisms through which these ingredients interact with paper are still not fully understood. To address this, systematic and quantitative experiments were performed using controlled model inks containing water, glycerol, ethylene-glycol oligomers, and selected surfactants to clarify how ink formulation and substrate properties drive liquid transport, pore–fiber exchange, and the resulting deformation of cellulose-based porous media. The work first quantifies the transient deformation of paper following deposition of co-solvent solutions. Grid projection metrology, sheet-length monitoring, and white-light interferometry were used to resolve expansion in the cross-machine and thickness directions. The deformation depends strongly on composition and exhibits anisotropy consistent with the known structural orientation of paper sheets. Co-solvents generate persistent expansion after drying, originating from their retention inside the fiber walls. The amplitude of this permanent expansion increases with co-solvent content up to roughly 50 wt% and decreases at higher concentrations. This non-monotonic dependence reflects the role of water for fiber plasticization: at low to intermediate compositions, the initial water softens the fibers sufficiently to allow co-solvent ingress, while at high co-solvent fractions, the lower availability of water limits transport into the intra-fiber pores. These observations directly link measurable macroscopic strain to the time-dependent distribution of co-solvents within the pore-fiber network. The thesis then investigates pore–fiber transport dynamics by monitoring the thickness swelling of paper after droplet deposition using four non-contact optical techniques: white-light interferometry and microscopy-based thickness monitoring as the main methods, complemented by laser triangulation and confocal displacement metrology. The transient expansion strain in the thickness direction reveals two characteristic swelling timescales, which we interpret using the Berens–Hopfenberg framework combining transport and relaxation processes. Systematic variation of co-solvent type and concentration shows that the characteristic times increase approximately exponentially with co-solvent concentration and roughly linearly with molecular weight, while a non-polar liquid (hexadecane) confirms that swelling is tied to fiber uptake rather than mere inter-fiber pore filling. Adding surfactants such as SDS and Triton X-100 substantially accelerates the short-time swelling, but can reduce the persistent strain at high co-solvent concentrations, indicating a smaller fraction of co-solvent reaching the fiber interior. In the next step, the influence of ambient humidity and co-solvents on the moisture response of paper is explored. Sorption measurements show that introducing glycerol or PEG300 increases the moisture uptake and, once enough co-solvent is present, removes the sorption hysteresis seen in untreated sheets. The resulting isotherms are well described by a non-interactive model in which the total moisture uptake is captured by the weighted sum of the individual sorption behaviors of paper and co-solvent. Complementary swelling experiments show that the rate of pore--fiber transport depends strongly on the initial liquid content of the paper. Higher humidity or preloaded co-solvent accelerates this transport. In contrast, MgCl_2 added to the model ink retards it, while surfactant added to the ink speeds it up. These results demonstrate that the initial moisture content of the paper and the amount of co-solvent present strongly govern subsequent ink ingress. The next part of the work investigates how aqueous co-solvent solutions influence the UV-induced yellowing of commercial printing papers. Accelerated-aging experiments and fluorescence spectroscopy show that ethylene-glycol oligomers substantially increase the rate of fluorescence loss and visible yellowing, whereas glycerol has little effect. The measurements identify the degradation of fluorescent brightening agents (FBAs) as the cause of yellowing and demonstrate that both UV light and atmospheric oxygen are required for this process. Low-volatility co-solvents such as TEG, PEG6, and PEG12 maintain a liquid environment around the FBAs during UV exposure, which enhances their photodegradation, while faster-evaporating co-solvents such as EG and DEG evaporate earlier and therefore have a weaker impact. The final part of the work investigates how elevated temperatures modify the coupled evaporation and transport dynamics of aqueous co-solvent solutions in paper. Using conduction heating and infrared (IR) laser drying combined with optical transmission imaging and surface-temperature measurements, the study quantifies water loss, co-solvent redistribution, and the resulting deposit patterns. Conduction heating raises the temperature of the entire substrate, whereas IR laser exposure produces highly localized heating. As water evaporates more rapidly at higher temperatures, low-volatility co-solvents remain as the dominant liquid phase and continue to redistribute within the pore–fiber network. These results show how temperature-dependent viscosity, volatility, and molecular size determine internal redistribution pathways and final deposit morphology during conduction and IR-based drying. Overall, the thesis shows how multicomponent aqueous liquids move through, deform, and chemically affect cellulose-based papers under different conditions. By resolving the underlying pore–fiber transport dynamics and their sensitivity to co-solvent properties, humidity, UV exposure, and temperature, the work links measurable material responses to the physical processes that govern ink–paper interaction. This understanding provides a foundation for predicting how multicomponent liquids behave after deposition and supports more informed choices in ink formulation and substrate design aimed at improving print quality and the stability of printed products.