Avril Thomas is hosting A Small World--A postcard exhibition at the Magpie Springs gallery. It is the exhibition after the Weltraum exhibition in the 2016 Shimmer Photographic Biennale finishes. The postcards consist of works on paper, they are 6x4 inches and its international in scope.
The 100 or so works will be auctioned through an online auction site with the proceeds going to help raise money for a cancer charity.
This is one of the pictures that I am thinking of entering into the exhibition:
The picture of clouds on the cliffs near Kings Beach on the Fleurieu Peninsula, is made with a rangefinder 35mm Leica film camera, so the aspect ratio of the negative is 3:2, which if uncropped, will enlarge to print 4x6 inches.
Another possibility is this image from the Adelaide-Himeji Garden in South Terrace, Adelaide, which is also made with a rangefinder 35mm Leica film camera:
I'm inclining towards the latter image at this stage.