# Influence of Printing Substrate on Quality of Line and Text Reproduction in Flexography
## 4 Results and Discussion
### Analysis of Line Deformation  
Line deformation on the imprint is researched based on three printed lines' physical characteristics: line area, line perimeter and line width. Two types of line width were chosen for the analysis: 85 \(\upmu\)m and 170 \(\upmu\)m. The values of area and perimeter for 2.56 mm line length and line widths are shown in Table 1. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Line Width 8 px at 2400 ppi = 85 \(\upmu\)m**} \\ \hline \multirow{2}{*}{**Sample Types**} & \multicolumn{2}{c}{**Area (mm\({}^{2}\))**} & \multicolumn{2}{c}{**Area DEV (\%)**} & \multicolumn{2}{c}{**Perim. (mm)**} & \multicolumn{2}{c}{**Perim. (\%)**} & \multicolumn{2}{c}{**Width (\(\upmu\)m)**} \\ \hline \multirow{2}{*}{**Negative Shape**} & TAGET & 0.22 & 0 & 5.29 & 0 & 85 \\ \hline \multirow{2}{*}{**Negative Shape**} & UCTD & 0.19 & \(-\)13.6 & 7.45 & 40.8 & 74 \\  & OPP FILM & 0.18 & \(-\)18.2 & 6.19 & 17.0 & 70 \\  & CTD & 0.21 & \(-\)4.5 & 6.17 & 16.6 & 82 \\ \hline \multirow{2}{*}{**Positive Shape**} & UCTD & 0.25 & 13.6 & 7.30 & 38.0 & 96 \\  & OPP FILM & 0.27 & 22.7 & 5.85 & 10.6 & 104 \\  & CTD & 0.26 & 18.2 & 5.78 & 9.3 & 101 \\ \hline \hline \multicolumn{7}{c}{**Line Width 16 px at 2400 ppi = 170 \(\upmu\)m**} \\ \hline \multirow{2}{*}{**Sample Types**} & \multicolumn{2}{c}{**Area (mm\({}^{2}\))**} & \multicolumn{2}{c}{**Area DEV (\%)**} & \multicolumn{2}{c}{**Perim. (mm)**} & \multicolumn{2}{c}{**Perim. (\%)**} & \multicolumn{2}{c}{**Width (\(\upmu\)m)**} \\ \hline \multirow{2}{*}{**Negative Shape**} & TAGET & 0.44 & 0 & 5.46 & 0 & 170 \\  & UCTD & 0.40 & \(-\)9.1 & 6.46 & 18.3 & 154 \\  & OPP FILM & 0.38 & \(-\)13.6 & 5.99 & 9.7 & 147 \\  & CTD & 0.43 & \(-\)2.3 & 5.81 & 6.4 & 165 \\ \hline \multirow{2}{*}{**Positive Shape**} & UCTD & 0.45 & 2.3 & 7.05 & 29.1 & 173 \\  & OPP FILM & 0.47 & 6.8 & 6.14 & 12.5 & 181 \\ \cline{1-1}  & CTD & 0.46 & 4.5 & 6.06 & 11.0 & 177 \\ \hline \hline \end{tabular}  
* CTD = Coated Paper, UCTD = Uncoated Paper, DEV = Deviation, Perim.= Perimeter.  
\end{table} 
Table 1: Results of measuring of area, perimeter and width for two lines thickness of 85 \(\upmu\)m and 170 \(\upmu\)m printed in positive and negative shape on three different printing substrates. Line width can be directly connected with line spreading, which was obtained by measuring line area. All printed lines show a deviation from target values. This spreading of the line in the positive shape leads to an increase in the thickness of the line, and in the negative shape to the closing of the line. Higher deviation of line width occurs in the negative shape (\(-23\)\(\upmu\)m) in relation to the positive shape (\(+11\)\(\upmu\)m for \(170\)\(\upmu\)m line thickness). With a thicker line, the value of the total deviation in negative shape increases, and in the positive shape it decreases. For example, deviation for \(85\)\(\upmu\)m line thickness in the positive shape on coated paper is \(+16\)\(\upmu\)m, and for the line of \(170\)\(\upmu\)m the deviation amounts to \(+7\)\(\upmu\)m (Table 1). The average value of measured line width is correspondent with the measures of their area. This only confirms the authenticity of the measuring results. A more detailed insight into the print quality of lines printed in positive and negative shapes is shown by percentage deviation of line area and line perimeter from target value (Figure 4). The dotted line in the diagram shows the target value. Lines printed in positive shapes for all three printing substrates indicate mildly positive deviations of line area, and in negative shapes there are mildly negative deviations from the target area (Figure 4). The biggest percentage deviation from the target value can be seen on OPP film (\(22.7\%\) in positive shape, \(-18.2\%\) in negative shape for line width of \(85\)\(\upmu\)m). The reason is the surface characteristics of the material, which is non-absorbent; therefore, the ink spreads only on the surface of the material.