A while back I got my hands on four Weathering Powders from Kromlech, I have now tried them out a little and here's my thoughts. First of all I must say that these are the first Weathering Powders Iv'e tried so far so I can't really compare to any other company's products. They do look similar to the Forgeworld ones for example though.
Also as you will probably see in the coming picture examples below I've just tested these straight away, I'm a total newbie with weathering so bare with me that these examples probably isn't the best way to actually show how to use them for best effect.
The idea behind this review is to do from a newbies perspective and compare it to use normal colours like I did before, so take it for what it is.
As I said I was given four of the Powders, and powders I felt I most likely would use a lot. First of all the Orange Rust which I have tried out quite much already and will probably use a lot more in the future. For example you can see how I have applied the rust on the Nurgle Warriors below with Orange Rust as the last "highlight" of the Rust. It was easy to apply and I did that both with and without a mixture with the powder and Lahmian Medium.
In the next example below I have used the Orange Rust, Soot Black and Concrete Grey to give the Rhino a more worn look, compare it to the other side of the Rhino where I have only used normal colours.
All was really easy to do and was easiest when mixed with a little Medium, I probably went a little over board with the rust and should have painted that a little better I feel. In the lower part of the chassi I first applied Soot Black and then Concrete grey over that, around the vents I used only Soot Black.
In the example above you can also look on how I could make this effect on the barrel of a Cannon, I painted on Soot Black straight from the pot at first and then with Medium closest to the gun barrel. I then took some of it away with my finger to let some of the metal shine trough. This totally gives the cannon a new look and it looks like it has been used. You can do this with washes as well I guess but this was much easier and you don't have to wait for it to dry before you give it another coat.
So last Powder then was the Dark Dirt, I applied this in the upper Razorback picture. If you compare it with the lower pic there isn't a huge difference but the Powder does make it more realistic and I really like the effect it gave the Razorback. Doing this to one side took me like a minute to do, so it's really easy to do and fast.
Conclusion
I know that there are plenty of more refined methods of using Weathering Powders, but as a beginner I thought they where really easy to use and you got a nice weathering effect straight away. You could probably use washes and normal paints to get similar effects but I don't think that it would look as good and foremost it would be much more time consuming. Because using Weather Powders is really fast and easy method to use so these Powders from Kromlech is much recommended. So if you are interested in them be sure to check them out over at their website.