DETAILED DESCRIPTION OF THE INVENTION In the process of this invention photoresist films are applied to preimaged, patterned relief substrates by flooding the patterned relief surface with a swelling agent to a depth of such agent to cover at least the relief height, i.
e.
, at least 0.
00004 inch (0.
001 mm).
The term "swelling agent" means a chemical agent which swells the surface of the photoresist so that when swelling agent is absorbed by the photoresist, the photoresist becomes swollen and softened sufficiently to collapse into depressions surrounding the relief areas.
In this manner elimination of air entrapment and excellent conformation of the photoresist film to the substrate is achieved.
Subsequently, the normal steps of exposure and development are practiced.
Etching or plating of metal in the areas where the photoresist was removed as well as other operations can then be practiced as desired.
Practically any known photoresist film can be used in practicing the inventive process.
Photoresist films, also known as dry film resists, are exemplified in U.
S.
Pat.
Nos.
3,469,982 and 3,526,504 which are incorporated herein by way of reference.
The photoresist may be an initially readily soluble, negative-working photohardenable layer (negative-working photoresist) or an initially poorly soluble photosolubilizable or photodensensitizable layer (positive-working photoresist).
Photohardenable materials are those which become hardened when exposed to actinic radiation and are preferably selected from photopolymerizable, photocrosslinkable and photodimerizable materials.
Such materials are usually characterized by having ethylenically unsaturated or benzophenone-type groups and are described in U.
S.
Pat.
Nos.
2,760,863; 3,418,295; 3,649,268; 3,607,264; and 3,622,334, for example.
Photosolubilizable and photodensensitizable materials are those which are solubilized or decomposed, rather than polymerized, in areas exposed to light.
When the latter are removed, the unexposed areas remain on the surface as a durable positive resist
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