Using OAKTON Meters to troubleshoot fountain problems

 

PROBLEM
CAUSE
CORRECTION

1. Toning, Tinting, Scumming

An irregular film of ink printing in the non-image areas of a plate.

  1. Incorrect pH or conductivity.

  2. Insufficient gum or wetting agents in fountain solution.

  3. Plate improperly exposed or under-developed.
  1. Check and/or correct pH and conductivity. (See meter instructions.)

  2. Check mixture of fountain solution.

  3. Use gray-scale when exposing plates; fully develop per directions.

2. Ink emulsification

Too much water in the ink.

  1. Incorrect pH or conductivity.

  2. Fountain solution mixed too strongly.

  3. Too much wetting agent in fountain solution.

  4. Ink tack too low.
  1. Check and/or correct pH and conductivity as explained above

  2. Mix fountain solution as explained above.

  3. Reduce gum, alcohol or alcohol replacement.

  4. Add binding varnish to ink too thin from can or lower amount of reducing compound used on stiff ink.

3. Roller stripping

Ink rollers do not accept ink, usually in bands around the rollers.

  1. Fountain solution too acidic.

  2. Running too much water.

  3. Conductivity of starting water too high.

  4. Glazed rollers.

  5. Worn rollers.
  1. Check pH of fountain solution. Adjust as above.

  2. Establish a new ink-water balance.

  3. Use distilled, deionized or RO-purified water.

  4. Deglaze rollers with hot water and deglazer.

  5. Replace worn rollers.

4. Ink not drying

Ink remains wet too long, causing problems with offsetting, smearing, color trapping and perfecting.

  1. Fountain solution too acidiic.

  2. Running too much ink.

  3. Ink not compatible with printing stock.

  4. Ink has emulsified.
  1. Balance fountain solution as explained above.

  2. Reduce ink to almost zero, then build-up in small steps for new ink-water balance.

  3. Match ink to stock.

  4. See Ink Emulsification above.

5. Plate blinding

Plate is not accepting uniform ink film or not accepting ink at all.

  1. Fountain solution too acidic.

  2. Too much gum in fountain solution.

  3. Plate surface contaminated.

  4. Too much water.
  1. Balance fountain solution with meters as explained above.

  2. Mix fountain solution correctly.

  3. Clean plate with quality plate cleaner, then rinse well with water.

  4. Reduce water; establish new ink-water balance.

6. Plate wear

Image on plate wears or breaks-down prematurely.

  1. Fountain solution pH incorrect.

  2. Too much pressure on plate from blanket or rollers.

  3. Ink tack too high.

  4. Running too much ink.
  1. Check and/or correct pH and conductivity as explained above.

  2. Check and/or adjust packing and roller pressure settings.

  3. Add reducing compound to ink.

  4. Reduce ink settings and establish new ink-water balance.

Technical information courtesy of Lithco, Inc.
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