I held a 1:1 plein air painting day with an artist called Rosie Copeland. Typical it was a windy grey day but actually was easier as it was stable light, so we weren't chasing shadows or squinting into the sun.
We covered a lot of ground from boards, gesso, equipment, my painting colours, colour mixing...viewfinder. Rosie really liked my viewfinder as I'd made a small hole so you can isolate colours and compare them to others in your scene.
I got the painting home and wiped it back (below pic) straight away so it didn't dry. The colour was left but no form, I repainted it the next day while it was fresh in my mind, helped I'd already done the same scene last August.
There is too much foreground so I shifted it all down and increased the scale up a bit and reinstated the shapes over the top....