All constructive criticism is most welcomed as always.
Hey Karel,
Really thought provoking set.
I think that the light works well on number 2 and number 6.


The rest not so much. There are some good ideas but need some need more refinement. You have to consider why you are lighting a subject a certain way. So that the lighting is consistent with the story/message/image you are trying to communicate in your photographs. It is not just a case of finding a subject and marrying it up with any funky lighting technique that you choose. As Ansel Adams said "There is nothing worse than a sharp image of a fuzzy concept."
That said it is important to continually experiment with different ways of lighting subjects. Seeing how and learning how different lighting effects are achieved. This will give you ideas for how to use the techniques to create those finished concepts. I do and take many unfinished images along the way to producing the image I show.
For example, this idea has a great deal of potential

the light coming through the stalk of the anemone looks great. But the most attractive feature on the anemone (tentacles) is not lit. One factor that can help an image like this is to give a reason for the backlight - by having a model above the anemone with a torch. Now we know that it is not the model's torch that is creating the backlighting, but to the average viewer the image makes more sense. Also in this case the model will give the image more depth. It is about recognising the potential in an idea (good ideas are precious) and then really making the most of it.
Here is a similar example from my photography. On the first dive I was just playing around with back lighting various subjects. Seeing how they took the light and the effect of various factors, like distance behind the subject. By the end of the dive I had some nice pictures (the image on the left) and particularly like the ones of the crinoid. I had also learned where I had to position the off camera strobe to get this effect.

This is a nice picture, but I felt it was an incomplete concept. A bit too simple. I could do more with this idea. So I decided to re-shoot it on a late afternoon dive with more background and model + torch. I would have liked the torch to have been a little stronger so it really looked like it was what was lighting the crinoid. But I felt this was a good use of this idea. Some may prefer the first image, that's photography for you.
Alex