W21 – Leaflet

1. Prepare the contact of the strips of offset plate with the strips of paper:
   1. Remove the light sensitive layer from three strips of aluminium offset plate by rubbing them with cotton wool soaked in stop-out solution.
   2. Rinse the strips thoroughly with water and keep them drenched in water or fountain solution.
   3. Put the wet strips of plate with 15 mm distance side by side on the sheet of glass with the cleaned side up. Keep the strips flooded with water or fountain solution.
   4. Put strips of the paper to be tested, paper strips “T” (scumming) and paper strips “O” (non-scumming) with 15 mm distance across the plate strips.                                                                                            NOTE: Do not use 40 mm from the top and bottom of the plate strips in connection with possible fingerprints.
   5. Record the sequence of the paper strips.
   6. Cover the strips with a sheet of blotting paper soaked in tap water of fountain solution and pour tap water or fountain solution on the blotting paper.

NOTE: The blotting paper and the plastic foil (see point 1.7) should not cause scumming. Before using these materials in a test they have to be examined following the method described in this Information Leaflet

1. Cover this combination (glass, strips and blotting paper) over with plastic foil (see note in point 1.6).
2. Leave for about 3 hours.
3. Touch the button PRINT to rotate the 1st shaft into the start position.
4. Apply 0,19 cm3 of IGT offset ink to a segment of the inking unit and dis-tribute the ink during the preset or desired time.NOTE: It is not advised to add some ink after a test.
5. Place the printing disc on the printing disc shaft of the inking unit and ink the disc during the preset or desired time.
6. Take a wet plate strip from the sheet of glass and mount it on the sector by attaching the beginning of the test strip into the front clamp and if desired, fixing the end of the test strip on the sector with a piece of tape.
7. Remove the printing disc from the inking unit and place it on the 1st printing disc shaft of the tester.
8. Press both side buttons to make a print, if activated to move the camera downward to make a scan and to come into the end position; then release the side buttons.
9. If the camera is activated:
10. The test strip is assessed; if finished the camera moves upward.
11. Save or discard the results
12. Observe the offset plate if ink has been transferred to the location of the strip, which had contact with the paper “T”:
13. If no ink has transferred, repeat points 7 thru 9 until ink has transferred at the location of paper “T”.
14. If ink has transferred, continue with point 10.
15. Remove the plate strip from the sector.
16. Check on which parts of the strip ink has been deposited as pointed out in the chapter “Assessment”.
17. Remove the printing disc from the tester and clean it with the rags and naphtha.
18. For a next test start with point 3 or touch BACK and start with point 2. It is recommended to perform the test at least three times per sample.
19. After having finished the tests, touch BACK and clean and store all parts as described in the manuals.
20. Make an accurate record of the conditions and the results of the test and refer to W21-AMS.

Assessment

1. Examine the plate strip visually which parts have accepted ink (see figure 2):
   • Paper “T”: the plate accepted ink.
   • Paper “O”: the plate did not accept ink
   • Paper to be tested:
     The plate accepted ink, so the paper is causing scumming
     or
     The plate did not accept ink, so the paper does not cause scumming.
2. Repeat point 1 for each test strip.