Can material selection start before grammage is known?

Yes. Begin with the intended use, finished dimensions, structure, quantity, and printing and finishing plan. Describe the colour, surface and handfeel you want. For catalogue text pages, IMPRINT and white MONO are possible starting directions; a beauty carton brief may call for comparing SOFTSKIN and HALO. Once candidate grades are selected, use printed, folded or bound prototypes to determine the required specification. Grammage is mass per unit area; it does not replace caliper, stiffness or assessment of the complete pack. Mark undecided values as pending. Confirm available specifications, processing suitability and order conditions for the chosen grade.