Date of Award


Degree Name

Master of Science


Chemical and Paper Engineering


Paper Engineering, Chemical Engineering and Imaging

First Advisor

Dr. Raja Aravamuthan

Second Advisor

Dr. David Peterson

Access Setting

Masters Thesis-Open Access


The goal of this experiment is to investigate how changes in the size and number of ink particles will affect the final brightness of the filter pad.

It was assumed that any differences in brightness of the used Millipore filters were due to change in the average particle size, given the same mass of ink solids on each filter. However, such simplified interpretation of image analysis proved to be inadequate to solve this complex problem.

The correlation between the particle area, number of particles, and brightness drop was established using an algorithm based on the particle area and the square root of the number of particles. The proposed method remains in accordance with the basic assumption that smaller particles are more efficient in paper discoloring due to their high numbers. Therefore, the particle number for tested size ranges has been recognized as a main cause of the brightness drop. The role of the area factor is meaningful only for the biggest particles (measured in tens or hundreds of thousands of square microns).

The proposed method is coherent and provides good correlation for all detected numbers and sizes of the particles.