Here is two tone grout installed out in UBC Vancouver. The floor is a mix of Italian White and Black Marble. To insure this was done perfectly I advised my clients (under my setter's recommendation) to allow the black grout to cure and be sealed. We left the black grout for over a week I think and then I installed three coats of enrich in seal. Then we taped off the floor a couple days later and did the white. Same process. Be careful with two tone grout installs. There is no room for error. And a mistake is set in stone sort of speak. Make up that test board and don't practice on your new floors. Good Luck. JW .

A good, penetrating sealer (DuPont's "Stonetech" is a good example) should be used before grouting as it prevents a haze from forming on the slate...sometimes hard to get rid of. The sealer will simply "buff" off of the glass with a cotton cloth or towell. After the grout has cured for several days, apply the sealer again and buff the project again. Note! If you use an "Enhancing" sealer, it will tend to bring out the colour and character of the slate more. Dampen a piece of the slate to see what the result should look like....

We used Dupont Bulletproof on our slate and it is completely clear, without enhancing. You can also call Dupont and they will send you samples. That way you can test without making a large investment in product.

Yvette Im sorry your upset, It does look lighter in todays photos to me. You have very poor photo quality and in truth you are comparing a Showroom floor with white marble or glass contrast relfecting and a complete different lighting schematic to your tub alcove. There is some solice in lighting. This is repeated on these forums time and again. Stone itself comes in dye lots and VERIES drastically. Stone wicks moisture, from thinset substrate and grout as it cures it gets darker before it lightens. Some thinsets can take 30 days to fully cure, some portland grouts do normalize over 7-10+ days. and there is a dozen things that can go wrong with hand mixed and installed grout. I cannot see close enough the details of your install but I can tell you I have had to watch sales people at tile shops like a hawk in that they are usually not a person to take advise from. Can you be 100% certain they sold you the proper color/brand or did they sell you something similar to sell you something. ? You should have more recourse if you Payed a tile professional to source and purchase the materials themselves grout included and if you have a contract and stayed hands off. One thing homeonwers dont consider when they get involved with these things is the importance of putting all the liability in the contractors hands to afford recourse. People that do the shopping finding deals choosing materials, and then hiring labor have little to no recourse so i hope thats not you.. I suggest further patience and see how it lightens, play with lighting and start to focus on other aspects of your room..