Scavengers for oxidized developing agents are frequently included in a color photographic element to prevent a color-forming reaction of the oxidized developer at an undesired location within the element. For example, it is generally undesirable for an oxidized developer species to diffuse away from the color-forming imaging layer where it was generated to another imaging layer, where it forms undesired dye of another color. This undesirable effect can be prevented or mitigated by ballasted developer scavenger compounds incorporated in an interlayer between two color-forming imaging layers.
In addition to this just mentioned use in interlayers to prevent color contamination, oxidized developer scavengers may also be employed within a color-forming imaging layer to control color fog and adjust the tone scale of a dye image.
Oxidized developer-scavenging compounds are typically ballasted to enable their incorporation in a particular layer within a photographic element while preventing their diffusion from that layer during coating and subsequent keeping and processing. The most commonly employed scavengers are ballasted polyfunctionalized aromatic compounds containing multiple hydroxy, amino, and sulfonamido groups, and combinations thereof, for example, hydroquinones, catechols, pyrogallols, sulfonamidophenols, aminophenols, disulfonamidophenols, aminosulfonamidophenols, and the like. In general, unless at least one of these functional groups is protected by a blocking group removable during processing or other masking means, a scavenger incorporated in a photographic element may exhibit photographic reactivity, usually with undesirable results, prior to color development processing. This is especially likely with polyhydroxysubstituted scavenger compounds containing two or more unprotected hydroxy groups.
Various coupler compounds that release oxidized developer scavenging moieties have been disclosed in the art. For example, U.S. Pat. No. 5,084,373 discloses photographic elements containing couplers that comprise various yellow, magenta, and cyan dye-forming moieties, mostly ballasted but a few unballasted and carboxy-solubilized, and coupling-off moieties that are scavengers for oxidized developer. Similar coupler compounds are disclosed in EP 0383637.
U.S. Pat. No. 4,477,560 discloses methylenebis coupler compounds, each comprising a ballasted and an unballasted dye-forming moiety. U.S. Pat. No. 5,128,237 discloses a direct positive photographic material that contains couplers having ballasted dye forming moieties and oxidized developer scavengers or scavenger precursor coupling-off moieties.
EP 0284099 discloses compounds that are purported to be anti-color staining and anti-color fogging and have unballasted dye-forming moieties substituted with various alkali solubilizing groups, preferably carboxy, and coupling-off moieties is that are ballasted reducing agents. EP 0322904 discloses couplers containing ballasted dye-forming moieties and aryloxy coupling-off groups that include --NHSO.sub.2 NR.sub.1 R.sub.2 substituents.
JP 63-110451 discloses couplers containing naphtholic or phenolic dye-forming moieties with carboxy solubilizing substituents and ballasted 2,4-disulfonamido coupling-off groups.
Couplers releasing scavengers for oxidized developer are also described in J6 1084646, J6 1086751, JO 3160442, and JO 2184848.
The disclosures of the eleven references just described are incorporated herein by reference.
Also well known in the art are dye-forming coupler compounds whose structures include diffusion-preventing ballast groups to enable their incorporation in a particular location within a photographic element but which produce dyes that are eliminated from the element in the course of processing. Such couplers are usually referred to as "wash-out couplers," regardless of the actual dye elimination mechanism, for example, diffusion, decomposition, decolorization, and the like.
Naphtholic wash-out couplers that release various photographically useful groups (PUGs) during processing, methods for making them, and photographic materials containing them are described in, for example, U.S. Pat. Nos. 5,151,343, 5,264,583, and 5,283,340, the disclosures of which are incorporated herein by reference. U.S. Pat. Nos. 5,286,859 and 5,358,828, the disclosures of which are incorporated herein by reference, describe wash-out couplers whose PUG coupling-off moieties comprise bleach accelerator releasing compounds (BARCs). Photographic elements comprising combinations of a bleach accelerator releasing compound (BARC) and a development-inhibitor releasing (DIR) coupler are described in U.S. Pat. No. 5,300,406, the disclosure of which is incorporated herein by reference.
As discussed above, coupler compounds that efficiently scavenge oxidized developer and form dyes removable from photographic elements during processing are very useful for improving the quality of color photographic images. There is an ongoing need for new, highly active, oxidized developer-scavenging couplers that are readily synthesized and purified, are stable during long-term storage, and release coupling-off moieties that are photographically inert. The present invention meets these objectives.