To give you some idea:
One coat of Garden Shades, applied evenly - just enough for the wood to almost disappear. I chose a pale blue called 'coastal mist'. Darker colours will produce a much more striking result, particularly terracotta, sage, holly, and iris. My camper is a mid to dark blue so needed lighter interior panels to brighten interior.
Once you have even coat of paint, allow to dry for several hours. The paint slowly soaks in in some places but stays more on the surface in others. If you can leave overnight, even better.
Next very lightly sand until smooth and/or until you feel they look right but don't go mad. Remove all dust. Very soft brush useful.
Below: Photographed indoors - Paint wash with one initial coat of water-based silk varnish (another yet to be applied).
Photo taken outdoors with second coat of clear varnish:
Overall it hides any very dark areas of the plywood and gives it a subtle colour (depending how much you apply) but still obviously wood. If you look at first pics in thread, the raw ply has a much darker, more yellow hue and uneven. Even if you varnished it, it'd still look like varnished ply. The paint wash just lifts it and you can use bright/strong colours if thats the look you wanted. I nearly bought 'sage' on the day which was a really nice but muted green but chickened out at the till and swapped. I'm sure household emulsion would work but this paint soaks in well on plywood
May try some other things on these panels - not sure until I get them in.
