This is my mark making tool that I made. So what i did was taking an old paintbrush and attaching two different types of feather at either side on the end. One was a slightly sturdier feather like that of a chapteh whereas one was more of a soft and fluffy texture like that stuffed inside a pillow.
I tested out my tool trying out both feathers, moving each in a specific way to obtain a marking. Some of the directions include gliding in downwards like in the bottom left markings, or flipping it side by side like in the top left ,markings. I even tries point the toll downwards whereby both feathers touch the paper and start to rotate them. What i achieved was a circular marking with a opaque contrast in the centre by the sturdier feather and a slight circular marking on the outside by the softer feather.
What i have discovered on my own was that since the soft feather is softer its soaks up the paint more so I have to drag it slightly across the surface in order to achieve an interesting patter. Unlike the sturdier feather where i can be a bit more aggressive and press it harder on the surface and achieve better markings.
Aside from the tool, one very helpful tip i learn was mixing acrylic paint with white glue to make it thicker and because of its stickiness it has helped me with some of my decalcomania prints like the one below.