I had to use a paper towel to lessen the light from above but then I picked up a lamp for the back and side lighting.
I too these shots by using a window. It’s a cloudy day so there is mostly defused light. I used copy paper as a way to get reflective light. I think I had better results in the backlight because it was easier to still see the faintest shadow compared to the light of the main light scarce.
Using the fill for me was a bit difficult at first. However, once I got the hang of it I was able to see how subtle and soft the shadows would get.
I used a white paper to fill the potato. It’s hard for me to get the window light. I tired to use lamp, but the result is not good. Finally, I still tried to use the light come from my window which make the potatoes better.