Ebonizing wood is a process which creates a chemical reaction in the tannins of the wood. The effect is to darken the timber and bring out the grain. This is a very useful trick if you want to give timber age or change the tone while creating a very natural finish. You can create an endless number of shades depending on the strength of your solution and there are other treatments you can use along side the ebonizing solution to create a wider range of effects.
I discovered this process when we moved into our current house. The original pine floors had a lovely soft grey colour after being hidden for 90 years under carpets and never sanded. What I really wanted was a pale grey limed oak parquet but as the budget did not allow, I had to improvise. Which consequently is the story of my life and the reason behind 90% of all my creative endeavours!
When you sand pine floors they lose any patina or colouration to reveal a very warm yellow tone. So why not just whitewash the floor boards or use a tinted oil? Well the difference in this process is that you bring out the grain of the wood rather than covering it up with a universal wash. It doesn't sound earth shattering but honestly I have not been able to replicate the beauty of this finish despite experimenting with all sorts of products.
N.B. If you are planning on undertaking this there are a couple of things that you should know.
1. I do not recommend applying this to new pine floorboards. I did this on a recent project where some of the floorboards had to be replaced. The floor lay untreated for a few weeks and when we ebonized them, there were very distinct lines where the boards had not been exposed to the sun - i.e. where the shadows fell in the room. My conclusion is that the sunlight effects the tannins, creating very dark areas in distinct lines. Even if we had treated the floor straightaway we had no way of knowing how much sun each board had been exposed to before treatment so I do not recommend ebonizing new boards. Old boards have had decades to mellow which is why I think we haven't had any issues on older floors.