A grout colour on a printed chart looks small and self-contained. On a tiled wall, it becomes a repeated network of lines. The same shade can make the joints recede, emphasise the tile pattern, or reveal small variations that were difficult to notice in a loose sample.
Put the actual tile beside the proposed grout before deciding. A showroom display may use a different tile batch, finish, joint width, or light source. Those differences can matter more than the name printed on the colour card.
Make the sample resemble the installation
Ask the installer whether a small sample board is appropriate for the chosen products. Use the intended joint width and follow the grout manufacturer’s mixing, curing, and cleaning instructions. Assess it after the specified curing period, rather than judging freshly applied material as its final appearance.
View the board where the tile will be installed. Check daylight and the artificial lighting normally used in that room. Hold a wall sample vertically; a board lying on a table may catch light differently from the finished surface.
Look at the whole pattern
Stand back as well as looking closely. High contrast may make a layout feel more graphic, but it can also draw attention to every joint. A closer colour match may create a quieter surface. Neither choice is automatically better; compare the effect with the rest of the room.
Colour is only one selection criterion. Confirm that the grout is suitable for the tile and location, and discuss cleaning and maintenance with the installer. Movement joints and sealant requirements are separate technical decisions, not something to resolve by choosing a matching grout shade.
Keep a labelled record of the approved product and sample. That gives the installer and homeowner the same reference when work begins. A few minutes with a realistic sample can prevent a disagreement based on two people imagining different versions of “light grey.”