Photo-polymerization and development process which produces dot-etchable material

Claim 2

A process of image reproduction which comprises imagewise exposing to actinic radiation a photopolymerizable element which comprises a support bearing a photopolymerizable layer containing actinic radiation absorbing material and having a maximum thickness of 0.015 mm and an optical density in the actinic region of at least 3.0, said photopolymerizable layer being the outermost layer of the element or being contiguous to a removable cover sheet or an overcoat layer which is at least partially soluble in or permeable to a solvent for the photopolymerizable layer, said exposure being through the outermost surface of the photopolymerizable layer or removable cover sheet or overcoat layer, when present, and wherein said exposure produces image areas having a hardened upper skin which rests on a softer undervolume having a lesser degree of polymerization or hardening, and then developing by removing the unexposed areas of the layer to form an image.

Claim 3

A process according to claim 1 wherein the thickness of the hardened upper skin is not more than about one-third the thickness of said image areas.

Claim 4

A process according to claim 1 wherein the image formed comprises a plurality of photopolymerized caps resting on underlying columns, the columns being soluble in a solvent in which the caps are insoluble.

Claim 5

A process of image reproduction which comprises (1) imagewise exposing to actinic radiation a photopolymerizable element which comprises a support bearing a photopolymerizable layer containing actinic radiation absorbing material and having a maximum thickness of 0.015 mm and an optical density in the actinic region of at least 3.0, said photopolymerizable layer being the outermost layer of the element or being contiguous to a removable cover sheet or an overcoat layer which is at least partially soluble in or permeable to a solvent for the photopolymerizable layer, said exposure being through the outermost surface of the photopolymerizable layer or removable cover sheet or overcoat layer, when present, and wherein said exposure produces image areas having a hardened upper skin which rests on a softer undervolume having a lesser degree of polymerization or hardening, (2) developing by removing the unexposed areas of the layer, and (3) reducing the size of exposed image areas by undercutting the edges of the hardened upper skin with a solvent for the softer undervolume and removing the hardened polymer and the edges of the hardened upper skin by mechanical action on the image bearing surface.

Claim 6

A process of image reproduction which comprises (1) imagewise exposing to actinic radiation a photopolymerizable element which comprises a support bearing a photopolymerizable layer containing actinic radiation absorbing material and having a maximum thickness of 0.015 mm and an optical density in the actinic region of at least 3.0, said photopolymerizable layer being the outermost layer of the element or being contiguous to a removable cover sheet or an overcoat layer which is at least partially soluble in or permeable to a solvent for the photopolymerizable layer, said exposure being through the outermost surface of the photopolymerizable layer or removable cover sheet or overcoat layer, when present, and wherein said exposure produces image areas having a hardened upper skin which rests on a softer undervolume having a lesser degree of polymerization or hardening, (2) developing by removing the unexposed areas of the layer, and (3) reducing the size of exposed image areas by undercutting the edges of the hardened upper skin with a solvent for the softer undervolume and removing the hardened polymer and the edges of the hardened upper skin by mechanical action on the image bearing surface.

Claim 7

A process according to claim 4 wherein the actinic radiation absorbing material is a dispersed pigment.

Claim 8

A process according to claim 4 wherein the photopolymerizable element has a removable cover sheet or overcoat layer which is removed prior to removing the unexposed areas of the photopolymerizable layer.

Claim 9

A process according to claim 4 wherein the photopolymerizable element has an overcoat layer which is completely or partially removed during the removal of the unexposed areas of the photopolymerizable layer.

Claim 10

A process according to claim 4 wherein the solvent is a predominantly aqueous solution.

Claim 11

A process according to claim 4 wherein the exposed image areas are comprised of halftone dots and the surface of at least some of the halftone dots in the exposed image areas on the side of the photopolymerizable layer which was exposed to actinic radiation is reduced in size by at least 5 percent.

Claim 12

A process according to claim 4 wherein the support comprises a polymeric film having a nonphotosensitive sub layer between the polymeric film and the photopolymerizable layer, the sub layer being soluble in a developer solvent, and the combined thickness of the sub layer and the photopolymerizable layer being no more than 0.015 mm.

Claim 13

A process according to claim 4 wherein the mechanical action is rubbing, brushing, or spraying.

Claim 14

A process according to claim 4 wherein the imagewise exposing comprises exposing through a continuous tone original and a vignetted halftone screen.

Claim 15

A process according to claim 4 wherein the element produced by the exposure and development is one of a plurality of color separation masks and the reduction in size of the exposed image areas is carried out to an extent that a composite color image produced with the several masks gives the full-color reproduction desired.

Claim 16

A process according to claim 13 wherein each of said color separation masks has been exposed through a different color separation negative and has been colored in a spectral region corresponding to the color separation negative.

Claim 17

A process according to claim 14 wherein the masks and color separation negatives correspond, respectively, to yellow, magenta, cyan and black.

Claim 18

A process according to claim 15 wherein the reduction of size of exposed image areas is accomplished with the masks superimposed in register.