IAP Exercise 2.4: Same Background, Different Model


Make portraits of three different subjects keeping the background consistent.

R0 ≈ 0


There has been much talk recently of the mystical R0 (pronounced R nought). So, what is it and why is it ruling our lives? And how could I photograph it?

The statistician and Professor emeritus of University Hospital Tübingen, Klaus Dietz describes it as follows:

The basic reproduction number R0 is the number of secondary cases which one case would produce in a completely susceptible population. It depends on the duration of the infectious period, the probability of infecting a susceptible individual during one contact, and the number of new susceptible individuals contacted per unit of time (1).

R0 first came to my attention when fascinated by the sudden change in UK policy regarding the coronavirus pandemic, I read the apparently influential Imperial College report released on 16th March 2020. Entitled ‘Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand’ (2). It outlines the predicted UK deaths under various levels of NPI and R0. The report suggested that if no NPI action was taken and with R0 of 2.6 the resultant UK deaths could reach 550,000.

Dietz further logically suggests that R0 may vary considerably for the same disease in different populations. Assuming the infectious period and the probability of infection (which I take to mean the inherent transmissibility of the Coronavirus) are reasonably consistent around the world, then the variability of R0 is primarily dependent upon contact with an infectious person.

Creative process

I use OneNote for most of my note-taking. Here is the germ of the idea for this exercise.


The brief calls for portraits of three different subjects with a consistent background. Building the three images up person-by-person signifies the composition of our entire population. The image is contemporary and is a response to the current normal. It also embarrassingly highlights the unfairness of the pandemic – we are almost able to achieve R0=0.

I find the image distasteful. It stinks of privilege and inequality. Of course, I am fortunate to be able to care for my mother. But the cost is that I am unable to make any other societal contribution. And the plight of so many others throughout the world is in stark contrast with mine.

And to measure the inequality in terms of an R0 value I’m sure most would be delighted with R0≤1. Such a tiny number measures so much.


(1) Dietz, K., 1993. The estimation of the basic reproduction number for infectious diseases. Statistical Methods in Medical Research, [online] 2(1), pp.23-41. Available at: <https://www.researchgate.net/publication/14938541_The_Estimation_of_the_Basic_Reproduction_Number_for_Infectious_Diseases>.

(2) Neil M Ferguson, Daniel Laydon, Gemma Nedjati-Gilani et al. Impact of non-pharmaceutical interventions (NPIs) to reduce COVID-19 mortality and healthcare demand. Imperial College London (16-03-2020), doi:

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