Artificially influence granite color tone

Thank you very much for the numerous responses. Above all, thank you, fach1werk, for the professional and constructive suggestion.

The window sills are polished. Do you have to remove the sealing first? If so, how can that be done?

Gladly. Unfortunately, I have to preface that I would never start it for us. The risk of ruining the window sills would be too great for me, and creating an even raw surface would take too much time.

Polished is smooth and does not necessarily absorb evenly; water will definitely gather on it. You could sand it with a fine grit, but you can't reach the corners perfectly.

Sealed is often "plastic." Where, for example, a thin film (acrylate in aqueous solution) has coated the particles, a reaction like silicification is no longer possible. You really wouldn't need to bother anymore.

The sample area provides clarity. But is it worth it? If I were restoring a treasure, I would consider a partial change so that the color temperature matches. That is usually enough. Maybe I would also just avoid letting hard white near it: something warm-toned only really stands out when you contrast it with something cold, i.e., if there were a clay wall next to it, you would perceive the room as warmer with the cold window sills than with warm tones. Too much harmony is dull and cannot enhance the desired effect.

Yes, I am aware of the risk of damaging the window sills. And of course, I would first test it on a sample piece. However, as of now, if the window sills remain as gray as they are now, they will have to be removed anyway and replaced with new ones; I have already been given an ultimatum about this. It is not just the color alone that is driving my wife crazy, but also the fact that we paid a significant extra charge for it, only to end up with something worse than the basic equipment. If we had not ordered the window sills, we would have received fairly neutral white window sills made of artificial stone.

I am attaching two pictures. One shows a sample piece, as we expected the sills to be, and the other shows an installed window sill.

Please place the sample piece on the built-in windowsill so that we have the same light color in the photo.

Why did you receive something worse just because a little bit of beige is missing? Natural stone is always more noble and beautiful than "white artificial stone." The surcharge was certainly justified. But if you think this is worse now, then you probably have to tear out the windowsills...

Please place the sample piece on the installed windowsill so that we have the same light color in a photo.

I will do it as soon as I am back on the construction site. But it will probably be only next week.

Why did you receive something worse just because it lacks a bit of beige? Natural stone is always more noble and beautiful than "white artificial stone." The surcharge was certainly justified. But if you think it is worse now, then you will probably have to tear out the windowsills...

I am not saying that artificial stone is more noble. It’s just that the color looks quite dirty. And if you don’t like the color, then it’s better to have neutral and inconspicuous windowsills than those you find ugly. It’s all subjective and a matter of taste; there are plenty of people who like gray. For example, one of our neighbors has a gray front door + a gray garage door + tiles in exposed concrete look. That wouldn’t be for us either.

And the price was definitely not justified. Unfortunately, at the beginning we had no idea what natural stone windowsills would roughly cost. Only when we saw the installed windowsills and realized that it wasn’t the type we wanted, did we come up with the idea of getting an offer from the same stonemason. The surcharge for granite was about 160% of the complete material price for us. Considering the removal of the basic equipment, we paid double for a type we don’t like at all (the latter, however, is our own fault).