Production process and individual integrity of a given tape as stability factors

Production process and individual integrity of a given tape as stability factors. While the chemical composition is an indispensable basis, the production process is regarded to be of even higher importance for tape stability: coating speed, proper dispersion of components, temperature and pressure of calenders are only some of the factors determining the stability of pigment layers. This may lead to a different performance between batches of the same type of tape, sometimes even with the same batch.

Additionally, the physical integrity of the tape surface plays an important role. Poorly serviced replay equipment can scratch the tape surface and create ports of entries for destabilising agents, such as humidity.

Chemical analyses are, therefore, of limited value in evaluating the quality and predicting the further life expectancy of tapes. Moreover: as the composition and production of tapes vary greatly, research results and recommendations valid for one type, or even only for a particular batch of tape cannot necessarily be extrapolated to others, let alone all tapes. In this respect generalising statements and/or recommendations by publications based on a limited number of normally not even identified sample tapes, should be regarded critically (Schüller 2014).

Figure 13: Pigment shedding: Chemical deterioration or poor manufacture?

Figure 14: Rare case of total loss of pigment. This is most likely a production problem.