Splotches or spiderweb effect on contours
Ink
Problem
1. Too thick.
2. Ink build-up on pad.
Solution
1. Add thinner.
2. Use faster thinner.
Cliche
Problem
1. Etching too deep.
2. Wrong screen ruling.
Solution
1. Produce new cliche with shallower etching depth.
2. Produce new cliche with fine half-tone screen.
Pad
Problem
1. Wrong pad shape.
2. Surface too rough.
Solution
1. Use more tapered pad form.
2. Replace pad.
Substrate
Problem
1. Surface becomes charged with static electricity.
Solution
1. Install ionizing unit on printing press.
Other
Problem
1. Humidity too low.
2. Cycle time too fast.
3. Intermittent operation of machine.
Solution
1. Raise humidity to approx. 60 % – 80 %.
2. Reduce printing speed.
3. Regulate to constant cycle times.
Improvement can be achieved by grounding press. Splotches or spiderwebs most often occur with materials
such as polystyrene, polycarbonate, or acrylics.
