Spots of poor ink pickup by pad
Ink
Problem
1. Too thick.
2. Dried out.
3. Wrong thinner.
Solution
1. Add thinner.
2. Clean cliche with thinner.
3. Use slower thinner or one suited to ink system.
Cliche
Problem
1. Insufficient etching depth.
2. Wrong screen ruling.
3. Surface physically damaged.
Solution
1. Produce new cliche with greater etching depth.
2. Test new cliche with different fineness of halftone screen.
3. Use new cliche.
Pad.
Problem
1. Too flat.
2. Surface roughened.
3. Pad swollen.
4. Surface too oily.
Solution
1. Use more tapered pad shape.
2. Replace pad.
3. Blow air on pad.
4. Clean pad (several times) or replace.
Substrate
Other
Problem
1. Pad is pushed onto cliche too strongly.
Solution
1. Decrease head stroke of pad.
If ink pulls on pad fibers during pickup, it is too thick and needs thinning.
