Travertine and limestone tiles are made of natural stone and can be very porous, therefore care has to be taken when fitting this type of tile.
It is advisable to use a white flexible cement and trowel the wall or floor with a 12mm notched trowel. Do not use spot method of fixing with this type of tile as this may result in the adhesive showing as a shadow through the tile.
Travertine tiles will not be able to be cut using a dry bed rail cutter, therefore all your cuts will be have to be done using a wet wheel electric tile cutter or an angle grinder fitted with a diamond tile blade. A 3mm spacer is recommended.
When grouting, to prevent picture framing effect, it is advisable to use a good quality tile stone sealer, this sealer will fill in all the pockets and pours in the surface of tiles and stops the grout leaving marks.