Rudy, if I may
The essence of photography is seeing the light.
Look for bright spots, dark shadows and reflections.
There is a lot more juggling the knife around relative to the light source than there is actually snapping the photo.
With a mirror finish blade you need something to reflect in it so it looks 'plain'.
No reflection of the camera, Rudy or the clock on the wall
To do this you can use a piece of poster board like kids use in school.
Again, moving it around relative to the light and what the camera sees takes some trial and error.
You'll be doing this more than snapping the photo.
Here is a set that I used for a cell phone photo.
The light source was the window on the right.
The white board on the left bounced some of the window light back to soften the dark shadows.
The board with the hole in it was used to hide the reflection myself and the iPhone in the blade.
Here is the photo
You can still see the window in the bolster. Another white board would've taken that away, but I ran out of hands
Anyway it is the "lesser of two evils".
Carefully look at what's going on with the light and you'll get used to seeing the variables and figure out ways to fix what's wrong.
Hope this helps