Thank you @Peter Roberts. I, too, was somewhat surprised by the impressionistic nature of some of the images, of which nature I was only partially aware at the time of shooting. My editing in post-production in this case was less than minimal.
Also today, strangely enough, I captured another photograph that in my opinion is reminiscent of painted or drawn arts. In this case it looks a bit like something between Japanism and "action painting". Something abruptly sketched on paper with a nib soaked in China ink. Even in this rendering my ex-post intervention was minimal and as always done in Darktable.
The Focal Encyclopedia of Photography defines diffusion as When light rays are reflected off or transmitted through a material in all directions, they are said to be diffused. Hence it defines a diffuser as Any light-scattering medium placed in the path of a beam of light to soften its character and a diffusion attachment as a Disc of lightly engraved or etched glass or transparent plastic........to blur part of the image forming rays and soften the definition of the picture. Chiffon and similar fabrcs can also be used in the same way.
Likewise John Hedgecoe in The Photographer's Handbook describes a diffuser as Any material that can scatter or diffuse light. The effect is to soften the character of the light.
You can of course buy diffusion filters to replicate this but they are by their nature predictable and produce a uniform effect. so when I said 'natural diffusion' (a made up term) I meant that you used something natural - the misty or pebbled glass - to produce images that are varied and unique in character.