The invention provides a color photographic element comprising at least one light-sensitive silver halide emulsion layer or a non silver-containing light-insensitive layer, in which at least one of these layers contains a colorless imidazole compound of formula (I) that undergoes less than 10% chemical or redox reaction with oxidized developer and which enables the photographic speed of the element to be increased by at least 0.05 stop without increasing granularity, compared to the same element without the compound, wherein the compound of formula (I) has the structure:
wherein
X is H or a substituent;
Z represents the atoms necessary to complete an unsubstituted or substituted imidazole ring, which may form part of a fused unsubstituted or substituted ring system containing no further ring heteroatoms;
wherein there is present at least one —NH group either in the imidazole ring or directly attached to the imidazole ring as part of X;
provided that
(a) when Z represents the atoms necessary to complete an unsubstituted or substituted benzimidazole ring, an —NH group is directly attached to the imidazole ring as part of X, and X is located between the imidazole nitrogen atoms;
(b) when the —NH group is located in the ring adjacent to the carbon atom bearing X, and X is located between the imidazole nitrogen atoms, the imidazole ring is not fused to a phenanthrene ring.
The compounds of formula (I) increase speed without a concomitant increase in size of the light-sensitive silver halide grains.
该发明提供了一种彩色感光元素,包括至少一个感光
银卤化物乳液层或非含
银的不感光层,其中至少其中一层包含式(I)的无色
咪唑化合物,该化合物与氧化显影剂发生的
化学或氧化还原反应不超过10%,并且相比于不含该化合物的相同元素,可将元素的感光速度提高至少0.05档,而不会增加粒度。其中,式(I)的化合物具有以下结构:其中X为H或取代基;Z代表必要的原子以完成未取代或取代的
咪唑环,该环可能是不含其他环杂原子的融合未取代或取代的环系统的一部分;在
咪唑环中或直接连接到
咪唑环作为X的一部分中至少存在一个—NH基团;前提是(a)当Z代表必要的未取代或取代的
苯并咪唑环的原子时,—NH基团直接连接到
咪唑环作为X的一部分,并且X位于
咪唑氮原子之间;(b)当—NH基团位于紧邻带有X的碳原子的环中,且X位于
咪唑氮原子之间时,
咪唑环未融合到
菲环中。式(I)的化合物可提高速度,而不会伴随着感光
银卤化物颗粒的尺寸增加。