FILTER FLARE - IMPLEMENTATION
The characteristic of filter flares is that the artefacts are flipped horizontally and flopped vertically of the original image. To implement it, flip and flop the element, often also along with a reduction to the overall scale, using a Transform Node, isolate the highlights with a 'luminance' key (e.g. a Keyer Node), premult, blur and merge 'plus'.
As to make it more interesting, we can combine a few layers, for example, one heavily blurred and merged to an extremely subtle degree, and another layer which just comprises the very highlights, merged to a higher intensity. In most cases, this effect should remain quite subtle, should be softly perceived rather than plainly visible.
