Citadel Baharroth Blue Layer Paint is designed to be multi-layered. This light blue color is slightly transparent, so you can use it to build your color over several layers until you're happy with it. Now the paint does require a bit of practice to use, but the results are well worth it.
The layer paints are best used as a 2-step highlight, so two paints for each color but this is a guideline. For example, Baharroth Blue can be combined with Temple Guard Blue. You start with the darker of the two and apply it to the surfaces that you want to eventually provide this light blue color.
Because the paint is a bit transparent you will continue to see the base color a bit, but by using Baharroth Blue together with Temple Guard Blue you can use that transparency to apply the layers. If you apply the lightest color after the darkest color in maybe 1 or two layers, the last highlight of the lightest color will ensure that you have a great result.
The color of Citadel Baharroth Blue (22-79) is similar to: The Army Painter Toxic Mist (WP1437); Privateer Press P3 Arcane Blue.