Photographic emulsions and elements capable of forming direct-positive images
AssigneeEastman Kodak Company
InventorsRoger M. Baralle, Marcel A. Compere, Maurice E. Pfaff, Frederic X. Jordi, Claude G. Goumont
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Abstract
Silver halide emulsions are disclosed containing silver halide grains capable of forming an internal latent image. Incorporated in the emulsions as a nucleating agent is a dihydrospiropyran bis-condensation product of salicylic aldehyde and at least one heterocyclic ammonium salt, thereby permitting a direct-positive image to be formed on imagewise exposure and photographic processing.
Claims20
A silver halide emulsion comprised of silver halide grains capable of forming an internal latent image and, adsorbed to the surface of said silver halide grains, a nucleating amount of a dihydrospiropyran bis-condensation product of a salicylic aldehyde and at least one heterocyclic ammonium salt.
A silver halide emulsion comprised of silver halide grains capable of forming an internal latent image and, adsorbed to the surface of said silver halide grains, a nucleating amount of a dihydrospiropyran of the formula ##STR6## wherein X and Y each independently represent a sulfur atom, a selenium atom, or a --C(R.sup.1 R.sup.2)-- radical,
- R.sup.1 and R.sup.2 independently represent lower alkyl of from 1 to 5 carbon atoms or together represent an alkylene radical of 4 or 5 carbon atoms,
- R.sup.3, R.sup.4, R.sup.5, and R.sup.6 each represent hydrogen, a hydroxy radical, or a lower alkyl or alkoxy radical of from 1 to 5 carbon atoms,
- Z.sup.1 and Z.sup.2 each represent the nonmetallic atoms completing a nitrogen-containing heterocyclic nucleus of the type found in cyanine dyes, and
- R.sup.7 and R.sup.8 each represent a ring nitrogen substituent of the type found in cyanine dyes.
In a photographic element comprised of a support and a silver halide emulsion layer comprised of silver halide grains capable of forming an internal latent image and, adsorbed to the surface of said silver halide grains, a nucleating agent,
- the improvement comprising
- said nucleating agent being a dihydrospiropyran bis-condensation product of salicylic aldehyde and at least one heterocyclic ammonium salt.
In a photographic element capable of forming direct-reversal photographic images comprised of a support and at least one color-forming layer unit comprised of a silver halide emulsion layer containing silver halide grains capable of forming an internal latent image and, adsorbed to the surface of said silver halide grains, a nucleating agent,
- the improvement comprising
- said nucleating agent being a dihydrospiropyran of the formula ##STR7## wherein X and Y each independently represent a sulfur atom, a selenium atom, or a --C(R.sup.1 R.sup.2)-- radical,
- R.sup.1 and R.sup.2 independently represent lower alkyl of from 1 to 5 carbon atoms or together represent an alkylene radical of 4 or 5 carbon atoms,
- R.sup.3, R.sup.4, R.sup.5, and R.sup.6 each represent hydrogen, a hydroxy radical, or a lower alkyl or alkoxy radical of from 1 to 5 carbon atoms,
- Z.sup.1 and Z.sup.2 each represents the nonmetallic atoms completing a nitrogen-containing heterocyclic nucleus of the type found in cyanine dyes, and
- R.sup.7 and R.sup.8 each represent a ring nitrogen substituent of the type found in cyanine dyes.
In a process of producing by surface development a visible image in an imagewise exposed photographic element having a support and, coated on the support, a silver halide emulsion layer comprising silver halide grains capable of forming an internal latent image and, adsorbed to the surface of the silver halide grains, a nucleating agent in an amount sufficient to promote surface development of unexposed silver halide grains,
- the improvement comprising
- developing in the presence of a dihydrospiropyran bis-condensation product of salicylic aldehyde and at least one heterocyclic ammonium salt.
A process of producing a direct-reversal dye image in a photographic element comprised of a support and at least one color-forming layer unit comprised of a dye-forming coupler and a silver halide emulsion layer containing silver halide grains capable of forming an internal latent image and, adsorbed to the surface of said silver halide a dihydrospiropyran nucleating agent of the formula ##STR9## wherein X and Y each independently represent a sulfur atom, a selenium atom or a --C(R.sup.1 R.sup.2)-- radical,
- R.sup.1 and R.sup.2 independently represent lower alkyl of from 1 to 5 carbon atoms or together represent an alkylene radical of 4 or 5 carbon atoms,
- R.sup.3 represents hydrogen, a hydroxy radical or a lower alkyl or alkoxy radical of from 1 to 5 carbon atoms and
- R.sup.7 and R.sup.8 each represent an alkyl substituent of from 1 to 5 carbon atoms, comprising developing the photographic element in a surface developer having a pH in the range of from 10 to 13 containing a color-developing agent.
Dependencies are inferred from the claim text.