Dynamic centrality metrics provide a quantitative assessment of the strength of communication between nodes in temporal networks, as well as the overall capacity of the network for the efficient transmission of information. In this article, the behaviours of two variants of the ‘communicability’ metric are examined in simple null models of uncorrelated temporal networks. Analysis of the long-time behaviour of the null models reveals a simple trade-off in the role of the parameters of the metric, suggesting methods to calibrate parameters and to adapt to temporal variations in the network properties. The null models introduced address two main classes of temporal networks (contact sequences and interval graphs), and their predictions are compared and contrasted with results coming from real-world telecommunications data.