This might be an odd review but for us make up geeks we've seen the fake freckles trend with this magic retouch (not for its intended use for roots). I use this mainly for fake freckles and honestly is a hit or miss as sometimes the applicator spray comes out very splotchy at first, therefore i recommend to test on a blank area and adjust the pressure to produce that natural fake freckle aesthetic.
Honestly, it seems easy to use for the fake freckles but you're probably better off with some other technique that has more precise and accurate result.
I really enjoy using this product. I have the BLONDE colour. Lots of greys sprouting around my hairline. I have lowlights and also use pink conditioner all through my hair, however the regrowth areas are always tricky. I find this really makes a huge difference in between salon visits. The spray nozzle is pretty good - an even distribution is important for a natural look. Just a very slight mist does the trick. and then blending in quickly with fingertips.
Tips: A little goes a long way. I started off being a bit too heavy handed with this product. It takes a bit of practice to get the spray action right - a fine mist is good!