Process for the manufacturing of slabs made of resin-bonded mineral grits comprising at least the phases of: - providing at least one supporting surface movable along a direction of forward movement; - supply of at least one mixture made of mineral grits and resins on said supporting surface; - compaction of said mineral grits and resins by compaction means to obtain a compacted slab; - hardening of said compacted slab by hardening means to obtain a finished slab provided with at least one exposed surface and having an intrinsic degree of porosity; - decoration with ink by digital printing by at least one digital printing device of said exposed surface according to at least one predefined design; wherein the process comprises, prior to said decoration and subsequently to said hardening and separate therefrom, at least one phase of increase in said intrinsic degree of porosity of the finished slab, adapted to promote the penetration of said ink in said finished slab and performed by treatment means arranged downstream of said hardening means and upstream of said at least one digital printing device with respect to said direction of forward movement, wherein said phase of hardening is performed by means of a first heating operation of said compacted slab at a temperature comprised between 100°C and 150°C and wherein said phase of increasing is performed by means of a second heating operation of at least said exposed surface carried out at a temperature comprised between 30°C and 180°C, and wherein said phase of increasing the degree of porosity is performed on the hardened finished slab, that is, once said finished slab has cooled down following said first heating operation. - providing at least one supporting surface movable along a direction of forward movement; - supply of at least one mixture made of mineral grits and resins on said supporting surface; - compaction of said mineral grits and resins by compaction means to obtain a compacted slab; - hardening of said compacted slab by hardening means to obtain a finished slab provided with at least one exposed surface and having an intrinsic degree of porosity; - decoration with ink by digital printing by at least one digital printing device of said exposed surface according to at least one predefined design; wherein the process comprises, prior to said decoration and subsequently to said hardening and separate therefrom, at least one phase of increase in said intrinsic degree of porosity of the finished slab, adapted to promote the penetration of said ink in said finished slab and performed by treatment means arranged downstream of said hardening means and upstream of said at least one digital printing device with respect to said direction of forward movement, wherein said phase of hardening is performed by means of a first heating operation of said compacted slab at a temperature comprised between 100°C and 150°C and wherein said phase of increasing is performed by means of a second heating operation of at least said exposed surface carried out at a temperature comprised between 30°C and 180°C, and wherein said phase of increasing the degree of porosity is performed on the hardened finished slab, that is, once said finished slab has cooled down following said first heating operation. - supply of at least one mixture made of mineral grits and resins on said supporting surface; - compaction of said mineral grits and resins by compaction means to obtain a compacted slab; - hardening of said compacted slab by hardening means to obtain a finished slab provided with at least one exposed surface and having an intrinsic degree of porosity; - decoration with ink by digital printing by at least one digital printing device of said exposed surface according to at least one predefined design; wherein the process comprises, prior to said decoration and subsequently to said hardening and separate therefrom, at least one phase of increase in said intrinsic degree of porosity of the finished slab, adapted to promote the penetration of said ink in said finished slab and performed by treatment means arranged downstream of said hardening means and upstream of said at least one digital printing device with respect to said direction of forward movement, wherein said phase of hardening is performed by means of a first heating operation of said compacted slab at a temperature comprised between 100°C and 150°C and wherein said phase of increasing is performed by means of a second heating operation of at least said exposed surface carried out at a temperature comprised between 30°C and 180°C, and wherein said phase of increasing the degree of porosity is performed on the hardened finished slab, that is, once said finished slab has cooled down following said first heating operation.