I have been searching for quite some time for actual tritium paint but have not been able to find any for sale, both in brick & mortar shops and the Web. Maybe it is a radiation hazard or something along the lines, I am not too sure. I have done numerous work on sights and also turned the iron sights on my SAA revolvers 'dark capable' with phosphorescent sight paints which are readily available.
They work very well and in low light conditions, give off a very clear indicator. However, unlike tritium, these paints are 'light activated' and do not carry their own energy source. Rather, it takes a short exposure to light to get them to kick in. I have found that they work even with a few seconds of exposure to an LED flashlight. But, if an emergency arises, let's say, at zero dark thirty and you need to achieve instant target acquisition in near pitch black conditions, that WILL present quite a problem. 'Charging' a sight will be the LAST thing you want to do when you have to clear a room or prepare to shoot at any given second.
Like
@Strykervet said above, sights are personal. They can and will mean life or death when you need them. If tritium paint is not offered for sale commercially I am going to have to invest in aftermarket sights. I am always a stickler for being prepared and shooting in dark conditions is something that is often easily overlooked in the subject of defensive handgun use.