What each defect looks like and what usually sits behind it. The correction depends on your core, your equipment and your batch, so it is settled at trial rather than prescribed here.
The film lifts out of an embossed logo or break line and spans across it, so the debossing goes shallow or disappears.
An extra white grade reaches full cover at a lower build-up, so there is less film sitting over the logo by the time the core is hidden.
Tablets adhere to each other or to the pan, and fragments of film or core pull away, leaving pitted faces.
Where the trouble starts on the press rather than in the pan, the moisture is in the powder and an adsorbent addresses it earlier than any coating change can.
A dimpled, matt surface rather than a smooth gloss, most visible under raking light.
Shade differs tablet to tablet within a batch, or between batches that were meant to match.
Metallic pigments shift more than conventional ones between daylight and tube light, so the inspection light has to be fixed before the shade is judged.
An enteric batch that looks correct fails the acid stage, releasing before it should.
The enteric band sits at 30 to 32 degrees at the bed against a 45 to 50 degree inlet, well below the film coating band, and that gap is the reason.
Coated tablets pass release but drift on stability. Colour changes, assay falls, or degradation products rise.
Colour drift on early stability pulls is usually the first visible sign, ahead of any change in assay.
An uncoated core that met specification falls outside it once coated, or disintegration time lengthens.
Running into one of these on a batch? Send us the core and the symptom and we will work back from there.