What an interesting newspaper cutting!
Many theories have been put forward about the origins of narrow boat decoration and I guess we shall never really know the exact process of evolution. However, a little theory, for what it is worth...
The flowers & landscape type of decoration was popular during the 18th & 19th century for those that could afford it. Pre Industrial Revolution, all manner of stuff was decorated by hand, often by craftspeople who were very skilled with a paintbrush. It has been commented on before about the similarity between the landscapes on Delft tiles and canal castle scenes.
From 1756 onwards, mass production of litho - transfer printed pottery and tiles started to take off in a big way, which meant - mass redundancy over a very short period for those very skilled painters. Locationally their work had been in the areas that were now linked by the New Canal Age - London, Bristol & Liverpool were centres of pottery production and were also transhipment hubs for such goods plus, the T & M Canal went straight through The Potteries themselves, the boats being used to transport from this area to other places.
So... faced with almost overnight joblessness, is it possible that some of these skilled painters diversified and started to work as signwriters and / or decorative painters? They certainly would have had the brush skills. Possibly, some started to work at boatyards or docks, or as general jobbing painters.
By the end of the 1700s, the previously relatively unadorned narrow boat started to evolve into the more traditionally decorated narrow boat as we know know it. This occurred as families started to live and work on their boats, which was not the case in the early days of the canals. This change was brought about by certain taxation changes at that time which made it difficult for boating families retain a land based dwelling. I am pretty sure that the new age boatwoman would have loved the opportunity to have some of those fancy flowers & pictures type stuff in her new but tiny home, and I do wonder if the fact that there were skilled artists looking for work, or already working at, the places that the narrow boats travelled through and to, meant that Narrow Boat Decoration evolved from this type of circumstanstial background.
Well, that's the little theory...... like I said earlier , we'll probably never know, but it's interesting to speculate. The above thoughts were brought about after I visited the Potteries Museums in Stoke a few years back and read about the huge change that transfer printing made to the livelyhoods of pottery and tile painters.