I can't see on the scans and I wasn't able to see on your video either, where exactly is that super high quality of Arches paper. If for one thing the Arches paper that you tested looks like it has a defective sizing.
The blue paint glazing had white spots while the edges were uneven on each and every brushstroke of colour you applied on it. That happens when the sizing is not strong enough or not consistent on the surface of the paper allowing the colour to spread and get absorbed in some areas of the surface and stay on top on some others.
The yellow washes looked washed out on both of the 100% cotton papers. To be honest I was expecting this to happen on the Fabriano Artistico as it is well known that Fabriano had the recent years some serious problems with its papers and particularly with the Artistico line. But I didn't expect that from the Arches ( though I have read some really negative reviews recently) that it is marketed as a top quality paper and it is by far the most expensive paper of all.
The papers that IMHO performed better on your test are the Fluid and the Fabriano 5 each on their own category.
The colours looked brilliant on the Fluid paper, the lines and edges were sharp ( something that is very important when you paint details), the blending results were decent for a non cotton paper and the diffusion of colours gave very good results too.
The paper Fabriano 5 gave the best results.
The colours looked brilliant, blended nicely, the glazing was as it should be with clean and sharp lines on all the length of the blue brushstroke and the diffusion of colour in the wet on wet application, though it wasn't that smooth, it was extented enough to make our lives easier when we paint wet on wet.
To conclude:
The most important thing for a watercolour paper is the sizing. If the sizing is not hard enough or it is defective then the paper will perform as an expensive blotting paper.
I can't see on the scans and I wasn't able to see on your video either, where exactly is that super high quality of Arches paper. If for one thing the Arches paper that you tested looks like it has a defective sizing.
The blue paint glazing had white spots while the edges were uneven on each and every brushstroke of colour you applied on it. That happens when the sizing is not strong enough or not consistent on the surface of the paper allowing the colour to spread and get absorbed in some areas of the surface and stay on top on some others.
The yellow washes looked washed out on both of the 100% cotton papers. To be honest I was expecting this to happen on the Fabriano Artistico as it is well known that Fabriano had the recent years some serious problems with its papers and particularly with the Artistico line. But I didn't expect that from the Arches ( though I have read some really negative reviews recently) that it is marketed as a top quality paper and it is by far the most expensive paper of all.
The papers that IMHO performed better on your test are the Fluid and the Fabriano 5 each on their own category.
The colours looked brilliant on the Fluid paper, the lines and edges were sharp ( something that is very important when you paint details), the blending results were decent for a non cotton paper and the diffusion of colours gave very good results too.
The paper Fabriano 5 gave the best results.
The colours looked brilliant, blended nicely, the glazing was as it should be with clean and sharp lines on all the length of the blue brushstroke and the diffusion of colour in the wet on wet application, though it wasn't that smooth, it was extented enough to make our lives easier when we paint wet on wet.
To conclude:
The most important thing for a watercolour paper is the sizing. If the sizing is not hard enough or it is defective then the paper will perform as an expensive blotting paper.