My friend, Don, has already done a review on these watercolour inks. So my review will be more of an add-on on what he's said. I took snapshots of all the drawings so you could see the saturation of the colors better. A scanner didn't do them justice. So apologies for the slightly dimmed down pictures as I don't have good camera lighting...or a very good camera.)
I'd describe this set as a colour mixing kit rather than a ready-to-use-out-of-the-bottle-ink set. That's because the colors that are given are pure and strong colors. Using them as they are will only give you very garish paintings.
Each bottle top comes with a little eye-dropper which encourages the artist to mix the inks into a palette (also provided) drop by drop so one can custom-make one's own colors. If you want nice results to come out of using this set, I would recommend that you first make yourself familiar with basic color wheel theory, tonal values (dark and light shades) and how colors are mixed to get other colours. There are lots of tutorials on these topics on the web.
Anyways, this is how I went about using these inks. First, I decided to mix 4 colours, chosen from the colour wheel. I wanted 3 analogous colors (colors side by side on the color wheel- YELLOW, GREEN, BLUE) and 1 complimentary colour (the color across from green- which is RED). I personally don't like garish or very bright strong colors so I toned all of them down by added a drop of SEPIA (from the bottle) into each color.
So I made:
Mustard yellow: Primary Yellow + a drop of sepia
yellowish green: Cyan + yellow + drop of sepia
a desaturated blue: Cobalt blue + Cyan + a drop of sepia
Burgundy red: Magenta + a drop of sepia
(The number of drops vary depending on how much color you are making. I made a very small quantity)
Next, I tried a similar drawing style to the one Brecht Evens (https://www.tumblr.com/tagged/brecht-evans) uses in his graphic novel “The Making Of” since it would be a good way to demonstrate these inks. I'm a fan of his art, by the way. It's a style that just uses watercolor, and no pen lines. To begin, I laid down the lightest shades and shapes of things I want to draw. Meaning, if I want to draw a man, I draw the entire silhouette of the man. When that's dry, I then add lines and details only on the inside of the figure since the shapes of the figure is already determined by the colour.
Note that just like regular watercolor, these inks do not work if you lay the ink line first, then color over it because the inks are not waterproof and will wash away. But you can layer a color over another color to create shades.
Lastly, I used the indian ink BLACK that comes with the set to add contrast to my painting. Most of the color I mixed were mid-tones. So needed black to get the darks into your picture. This is where knowing how to apply tonal values come in handy. I used black as solid black and also mixed it with a color to get a darker shade of the colour. To get a lighter shade of a color, I mixed the color with water. I noticed that there is also white ink in the set, but I didn't use that. Keep a bottle of water and nearby to wash your brush every time you use a new color or your palette color will get muddy.
The advantages of using these Pebeo inks instead of regular watercolor?
1)You get very saturated color. Regular watercolors are not as saturated as these.
2) You get a nice sheen over your drawing.
3) You don't have to keep mixing colors while you paint, except lightning and darkening the shades.
4) Good for painting a custom-made color as a flat color.
5) Good for drawings that use only the same few colors.
Instead of just mixing them in the palette, I'd also recommend getting small bottles where you can store you favorite color mixes so you don't have to dispose of them every time you finish a painting and want to wash your palette.
Any disadvantages of Pebeo inks?
1) The set is too big to bring outdoors for sketching. But if you transfer them into small bottles and bring out 3 or 4 of them, that could work!
2) Plastic ink bottles will leak if you forget to tighten them before storing.
3) Plastic ink bottles can be toppled easily so handle with care.
Do I recommend these? Yeah, It's fun! And I like the results they produce.