Thanks a bunch guys(and girl)!
It will be my pleasure to share with you how i made those...
Years ago i got a hold of some studio flash head, and played with it a bit... i was going for those water splashy lemon-lime-tomato... stuff...
But i had no gear and very little knowledge and needless to say, it was a disaster... and after that i spent some time every now and then, playing with water droplets and dropping things in water...
the ink came in the calculation...
it was some old aquarium u used back then...50-60 liters... and well, it was fun for solids, but when i started dripiing ink and paint in, it became... kind of a chore to empty all that water after few shots and pour in the clear...
so, i made smaller version... large surface and small... spacial depth...

40*25*5cm
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and a ping pong ball for reference of size... hehe

It holds around 5 liters of water but 4 is perfect for manipulation...
now, there comes the hard part...
What is a must is white background... sky works, wall works, but perfect for my use is diffusion part of passive reflector...
http://pcfoto.biz/Image/04241/Zilberica-5u1-110-cm.jpg
that milky semitransparent sheet from inside, its clear and nice, and its easy to fill it with light.., either window or some other source...
Fluorescent lamp is also great for that... now, for soft background and evenly distributed light, in that case works well if i place glass on the ironing board,
(this thing in case i gave wrong name), that white sheet around 50 cm in the back, and neon light, or day time window some 50cm on the back... so light is around 1 meter from the glass...
But, for the purpose, even close combination works...
or just white wall... or even white paper just on the glass...
and to show that to you guys and some other people, i made few shots just like that...
Baking paper is cheap, available and great for light diffusion so here i used that
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and light was directly behind the glass
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paper was between, of course

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I used one more lamp... you can see it ion the far end of the ...aquarium, and as reflection on the first image... its simple table lamp, and led bulb inside, but any kind works just fine...
It stands aside, to fill in the depth and give light to the paint... from front side it makes lots of reflection, but from the corner or side, it fills water with light and neons on the back are just for background...
of course, that is the set for high key photos...
combinations of distance and types of light will give different results...
Even handheld torch or flashlight can give epic result, as light passes thru cloudy water...
All in all, this is what this set gives



now... temperature of water, type of paint and even temperature of that paint, combination of different paints, addition of alcohol or distilled water in paint or water all have some effect...
I would not recommend oils or anything of the sort... it just doesn't work well for this...
grains can be great... sand or something similar might be fun to try, Potassium permanganate is orgasmic! but i usually use black and red ink for technical pen and some tempera and acrylic paints and those hard dry color for aquarel... watercolor...
also, all those effects act more or less different depending on kind of light used and setting of that side lamp(s)
I use continuous light because I'm poor *******, and besides i have no idea how flash could be used because of all that glass and refraction...
anyhow, once light is set, you will need some paper towels to wipe the glass on the outside and some metal rod, or wooden stick, something smooth and fine... bicycle wheel wire, car antenna, wooden pencil...something of the kind, to remove bubbles that gather on inside of the glass and to stir up the paint...
and then all what is needed is patience...
lots of tryouts , hits and misses, corrections to set... 50mm is great, macro also works great...

And one, maybe most important thing.,..
Light works on electricity... and every set that includes water, specially these amounts of water requires great deal of attention and carefulness...
Mind your cables, mind what you do... don't make my mistake...(once i spilled picther full of water on extension cord)
Just make sure you are super careful when playing like this, cover all fields, rise cables, think of worst case scenario, make sure you did your best to minimize the danger and damage in that case, act responsible and mature and... well, have fun...
those paints can get messy so, cover carpets with newspapers, start small, and develop on that, according to results and desire...