Zebest and Irey have tried to argue that the halos around the text are caused by a unsharp filter. However, there is a real problem with this: The halo is in the background, while the text is in the foreground, the unsharp filter works on the text layer only, unless the layers are somehow merged down but then the layers disappear.
Remember how Mara Zebest used to show how she ‘created’ a halo around the letters, but on closer scrutiny, the halo shows differences from the halo observed.
While the halo appears to be similar to the one on Obama’s, on closer scrutiny there are some relevant differences. The most obvious one is the presence of a dark interior within the ‘halo’, which is likely a side effect of the data filling used by the algorithm.