Ink chalking means weak binding of the pigment on the surface of the print. When rubbed, the pigment may come off as a dry trace. Check for this symptom before you decide that you just need to wait longer for it to dry.
How to recognize ink chalking?
Compare prints under identical conditions and check rub resistance after an appropriate amount of time. Observe whether the surface smudges or releases dry pigment. Retain samples to compare the results at subsequent stages.
The presence of a color mark alone is not enough for a definitive diagnosis. Issues related to drying or mechanical resistance can manifest in a similar way. Record the time of inspection and the conditions under which the test was performed.
Why does ink chalk?
Excessive absorption of the ink’s liquid components into the substrate can leave the pigment on the surface with an insufficient amount of binder. This is why the choice of both ink and paper is critical. Grammage alone does not define a substrate’s absorbency.
Check whether the paper, its batch, or the printing side has been changed. Also, determine if the ink contains any additives that may have altered its properties. Do not automatically attribute every defect solely to the ink.
Chalking vs. Not Drying – What’s the Difference?
| Symptom | What might that suggest? |
|---|---|
| The dry pigment comes off easily when rubbed. | Poor pigment binding, including possibility of chalking. |
| The layer smears or transfers to an adjacent sheet. | Fixing or drying problem; further inspection needed. |
This table helps you choose your checking direction. It does not replace the evaluation of samples and information about the materials used.
What to check in a print shop?
Prepare a sample of the unprinted paper and a printed sample. Note the name of the ink, any additives used, and the time elapsed between printing and inspection. Compare the defective print run with the most recent successful job.
For issues related to drying, please consult the guide: offset ink does not dry. Don’t add the dryer automatically: poor pigment binding and too slow drying require different decisions.
Will varnish solve chalking ink?
Do not use varnish as a way to conceal an unidentified defect. First, investigate the root cause and ensure the compatibility of the materials used. Evaluate any potential protective coating by testing the entire process.
At WIT, we can help you make the right choice. offset ink to the ground. Send samples and write what resistance the finished print should achieve.
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