Light colours seem to not display in the on-screen render (Spot colours, pantone and standard colours all seem to be affected in my testing)
I use a lot of block out white over colour backgrounds to add the desired effect.
Here is a test example from Illustrator using a very pale off-white colour.
Please then see below my testing lightly darkening it.
I have reset the Origami settings and restarted my system to no avail. It unfortunately does not resolve this issue for me.
To mask the number of different elements would take some time; and I would consider being able to overlay light-coloured elements important from a visual checking perspective.
Customer support service by UserEcho