Ceramic is somewhat porous. It absorbs moisture during setting. That can change its color. It will dry out. Was it rated for a shower? Some soft body ceramic is extremely porous and isn’t rated for wet areas because of that.

Please post photos. It could just be color contrast- the grout has more yellow than the tile so it is making the tile look grey, conversely a more grey grout makes the tile look warmer.

the tile is glossy and very reflective. I think the stainless steel appliances are changing the hue of the tile. After 2 days the tile had not returned to its original color.

Second photo, hard to believe I have a totally different look. Depending on time of day and amount of lighting, the tile seem to change.

It makes a difference to look at tile (or paint) on a vertical surface vs flat. The light reflects on it a different way. Do you have a picture from further back? To see how it looks with the rest of the space?

Check the boxes. Maybe the wrong color was delivered.

Is the first picture taken in the same lighting conditions as the second, or in a showroom?

Lighting, time of day, nearby elements all affect how tile will look. Tile, especially glossy tile, is a somewhat reflective surface and will pick up surround colors very easily. However tile can change to some degree especially over time. Skippack's suggest is an excellent one. I would do that and if there is significant color change I would contact your tile supplier and/or installer and get them to come inspect the job.

All boxes of tile are from the same lot. When I placed a tile from the same box against the backsplash it blended in with the wall. I have concluded that the stainless steel appliances and the high glossy reflective tile are why the tiles appear a much different color. I noticed the cabinets have a slight pale grey color depending on their location relative to the ss appliance. the grout being non reflective has maintained its color. Fortunately, the tiles work with the space as a whole. Now to choose a paint color for the rest of the walls. Thank you for your time, effort, and input.

I think it looks really nice!

From the last picture it all looks very nice.

It looks pretty in the last photo you posted. It may seem a bit different from what you expected but I think it looks great! It is one of my favorite tiles for kitchen backsplashes. :)

Does your room get any natural daylight? I think it's hard to see the color from the last photo. The room looks very nice, but I can't really see what color the tile is from the photo you've shared because the room is so dark.

I have one small window above sink. With a covered wrap around porch it blocks the sun as well.

The tile job and tile color looks wonderful. Tile color can be tricky and you are correct because color contrast of semi gloss tile is all about the surrounding light and other nearby colors. Thank you for sharing your pictures.

It looks terrific! (One tiny suggestion: get switch plate covers to match the tile color.)

If you take the valances off of the windows in the eat in area it will also allow a bit more light in.

I think the kitchen looks great and even though the tile wasn't exactly what you expected, I think it works well.

Oh, it could be totally your lighting. I count 5 ceiling cans. I'd add a few. Do you have undercabinet lighting? If not, I'd add it. There are so many threads in these forums about kitchen lighting. The common problem is that white cabinets appear yellow. There are standard expert recommendations about ceiling and kitchen lighting.

https://www.houzz.com/discussions/5224453/white-cabinets-look-yellow

Experts generally recommending the 4000K bulbs (LED of course). Changing the lighting can REALLY change the appearance of things.