It's really more of an exercise in trick photography than anything else, and most of the camera tricks available to the amateur 16mm film maker at that time are employed.
There is a lot of 'stop motion' - stopping the camera and either putting something into the frame, or taking something out, and then resuming filming giving the effect of something appearing or disappearing out of or into thin air.
But the 'double' effect used towards the end of the film, when Arthur's miraculous powers turn Evelyn into two people, is the ultimate in film trickery at that time.
To produce the effect meant exposing just half of the 16mm film with a blanking plate over the other half and then rewinding the film, blanking off the already exposed half, and then filming again.
By today's standards, the result was, perhaps, indifferent, but the true wonder is not that it was done slightly badly, but that it was possible to do it at all.
The film features Arthur Roberts and his two sisters - Winnie (later Winifred Oakes), who plays his wife and Evelyn, later Evelyn Ridgway, who was, until the end of the 1960s, the proprietor of the newsagents shop in Wheelock Street most recently known as 'Chisholm's'.
Evelyn plays 'a friend' making a memorable appearance (or should that be two appearances?) towards the end of the film..
Arthur plays the part of a man plagued by indigestion who is always looking for the ultimate cure, as is his wife, who tries all kinds of medicines to try to solve the problem.
The 'Double Strength' tablets which eventually fall onto the doormat and which Winnie slips into Arthur's drink prove to be not quite as advertised.
Then again could the whole thing be just a dream?
Probably - it's one of the oldest ideas in the history of film making and used to very good effect in this little masterpiece.
We believe that the house and garden used as locations for this film are in Westlands Road in Middlewich.
Note that when Arthur is relaxing in the sunny summer Middlewich garden, the newspaper he is reading carries stories full of the ominous doings of Hitler and Mussolini.
The storm clouds of war were gathering, but it all must have seemed millions of miles away from that secluded Middlewich garden.
We looked long and hard for some music to accompany this film and eventually struck gold with a website in New Zealand which specialises in transforming vintage player-piano (Pianola) rolls into Midi files.
We're very grateful to Robert for allowing us to use some of the music he has so painstakingly preserved to accompany this and other films in the series. We hope you'll agree that, as we've said on our YouTube Channel, the music fits the film 'like a glove'.
The selections used are 'Slipova' by Roy Bargy and 'Maple Leaf Rag' and 'Palm Leaf Rag' by Scott Joplin
We recommend watching 'Double Strength' on YouTube by clicking the link below.
WATCH 'DOUBLE STRENGTH' ON YOUTUBE
'Double Strength' and the other films in the Roberts Collection are now in the care of the North West Film Archive at Manchester Metropolitan University.