I suspect it's contrary to your objective of having attractive tile on which to walk, but there are a number of grip-enhancing paints on the market. Many are described as driveway paint with grip or driveway paint with grit.
Other links suggest adding job-specific grit to paint and from there one could extrapolate that the same grit could be added to a clear surface treatment.
Grit embedded tape is also on the market, far less attractive than a painted surface (opinion) and subject to unsightly wear.
An additional thought popped into my alleged mind. There is a product called Never-Wet, which is a hydrophobic coating. It's marketed under the Rustoleum brand and available at many big-box stores and Amazon. I have a package (somewhere) but have never used it. I recall the package instructions indicating that there's a slight cloudy effect to the application on some surfaces, primarily fabrics. I suspect that would not be a problem on the tile.
As water is creating the slippery effect, perhaps Never-Wet would remove the water and therefore the slippery.
A final resort would be to hire a portable sandblaster vendor or device and remove the slippery glaze of the tile. The coloration would likely remain but become subdued. Perhaps even a floor sander or similar device would enable suitable roughness.
Photo from Amazon link.
Answer from fred_dot_u on Stack Exchangefloor - Is there a way to make tiles outside a home not slippery? - Home Improvement Stack Exchange
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I suspect it's contrary to your objective of having attractive tile on which to walk, but there are a number of grip-enhancing paints on the market. Many are described as driveway paint with grip or driveway paint with grit.
Other links suggest adding job-specific grit to paint and from there one could extrapolate that the same grit could be added to a clear surface treatment.
Grit embedded tape is also on the market, far less attractive than a painted surface (opinion) and subject to unsightly wear.
An additional thought popped into my alleged mind. There is a product called Never-Wet, which is a hydrophobic coating. It's marketed under the Rustoleum brand and available at many big-box stores and Amazon. I have a package (somewhere) but have never used it. I recall the package instructions indicating that there's a slight cloudy effect to the application on some surfaces, primarily fabrics. I suspect that would not be a problem on the tile.
As water is creating the slippery effect, perhaps Never-Wet would remove the water and therefore the slippery.
A final resort would be to hire a portable sandblaster vendor or device and remove the slippery glaze of the tile. The coloration would likely remain but become subdued. Perhaps even a floor sander or similar device would enable suitable roughness.
Photo from Amazon link.
There are clear concrete sealants/coatings that can have anti-slip ingredients mixed in that can make the surface less slippery when wet. It would require continual mixing when applying so the anti-slip material won't settle out, but might be an option for you. Putting "concrete sealant ant-slip additive" into your favorite internet search engine should give you some options to consider.
We are remodeling an old (1865) home and I would like to put tile in the kitchen, but we also have two excitable large dogs who are getting older and liable to injure themselves on slippery tile (especially after they dribble their drinking water everywhere-also making slick tile a danger to people). I was looking at the “Stepwise” tile at daltile, which looks promising, but I didn’t see prices on the site which is always concerning. I found a place to check that brand out, but even after reading about COF/DCOF/SCOF slip ratings and I’m not sure I really understand what the numbers correlate to in a real world setting. Can anyone with superior tile knowledge or who has bought some good non-slip tile advise on Daltite or any other good brand/model and where they got it from? Obviously, a good quality to value ratio would be nice. I just moved close to Winston-Salem, NC, so if anyone has had a great experience somewhere relatively local to me, I would love to hear about that too. Thanks!