Thanks a lot for your replies.

I've done further investigations in this topic.
Seems like my La Veignette on plain water does indeed polish the scratches deom my Thuri as well as from my Zulu Grey.
It does also change the very apex of the edge.
Here are some pics in 160x magnification (sorry, my optical system makes pics only usable in the middle of the frame):
Name:  IMG-5754.jpg
Views: 203
Size:  22.5 KB
Name:  IMG-5750.jpg
Views: 215
Size:  20.2 KB

Now after those super light strokes on Coti, see how the form of that micro-micro-chip in the middle of the edge has changed its form...
The light source is located for all pictures at the left of the frame to make the scratches visible.
Name:  IMG-5771.jpg
Views: 231
Size:  20.5 KB


BUT: Seems like as soon as the Coti releases some garneds (autoslurry) into the water they start creating much coarser scratches.
Here is a sample picture, the diagonal scratches were comming from the same coti on plain water.
Name:  IMG-5882.jpg
Views: 225
Size:  28.5 KB
I am quite sure the more loose garneds in the water while finishing the higher the "slurry dulling" effect occures.
Think my La Veignette does autoslurry relativeley easy, perhabs if the edge is not refined up to a certain level its rughthness causes the coti to autoslurry much more.

How can I prevent my coticule from releasing those garnets?
Do you know some techniques beside to finish under running water? (my free hand finishing is not yet that consistent compared to honing on the bench)

Thanks a lot in advance

Regards

Philipp