Введение
Химические вещества, преобразующие скрытое изображение на фотопленке в видимое изображение.
При обработке фотопленки, пластин или бумаги, проявитель (или просто девелопер) представляет собой одно или несколько химических веществ, преобразующих скрытое изображение в видимое. Проявители достигают этого преобразования, восстанавливая галогениды серебра, имеющие бледноокрашенный вид, до металлического серебра, которое становится черным в форме мелких частиц. Преобразование происходит в желатиновой матрице. Уникальная особенность фотографии заключается в том, что проявитель действует быстрее на те частицы галогенида серебра, которые подверглись воздействию света. Если оставить в проявителе, все галогениды серебра в конечном итоге будут восстановлены и почернеют. Как правило, чем дольше проявитель воздействует, тем темнее становится изображение.
Химический состав разработчиков
Разработчик обычно состоит из смеси химических соединений, приготовленных в виде водного раствора. Для чёрно-белой фотографии три основных компонента этой смеси: 115
Developing agents. Popular developing agents are metol (monomethyl p aminophenol hemisulfate), phenidone (1 phenyl 3 pyrazolidinone), dimezone (4,4 dimethyl 1 phenylpyrazolidin 3 one) and hydroquinone (benzene 1,4 diol). Dimezone is thought to resist oxidation in solution better than Phenidone A, but it is not as available as Phenidone A. Dimezone is also known as Phenidone B.
Alkaline agent such as sodium carbonate, borax, or sodium hydroxide to create the appropriately high pH. Sodium sulfite to delay oxidation of the developing agents by atmospheric oxygen. Notable standard formulas include Eastman Kodak D 76 film developer, D 72 print developer, and D 96 motion picture negative developer. Hydroquinone is superadditive with metol, meaning that it acts to "recharge" the metol after it has been oxidised in the process of reducing silver in the emulsion. Sulfite in a developer not only acts to prevent aerial oxidation of the developing agents in solution, it also facilitates the regeneration of metol by hydroquinone (reducing compensation and adjacency effects) and in high enough concentrations acts as a silver halide solvent. The original lithographic developer contained formaldehyde (often added as paraformaldehyde powder) in a low sulfite/bisulfite solution. Most developers also contain small amounts of potassium bromide to modify and restrain the action of the developer The light sensitive layer or emulsion consists of silver halide crystals in a gelatin base. Two photons of light must be absorbed by one silver halide crystal to form a stable two atom silver metal crystal. The developer used generally will only reduce silver halide crystals that have an existing silver crystal. Faster exposure or lower light level films usually have larger grains because those images capture less light. Fine grain films, like Kodachrome, require more light to increase the chance that the halide crystal will absorb at least two quanta of light as they have a smaller cross sectional size. Therefore, silver halide crystal size is proportional to film speed. The metallic silver image has dark (black) appearance. Once the desired level of reduction is achieved the development process is halted by washing in a dilute acid and then the undeveloped silver halide is removed by dissolving it in a thiosulfate solution, a process called fixing. Most commercial film developers use a dual solution or "push" (pushes the films speed) development (compensating developer, like Diafine) procedure where the reducing agent e. g. hydroquinone solution soaks into and swells the gelatin then the film is introduced into the alkaline solution which activates (lowers reduction potential) of the developer. The areas with the most light exposure use up the tiny amount of developer in the gelatin and stop making silver crystal before the film at that point is totally opaque. The areas that received the least light continue to develop because they haven't used up their developer. There is less contrast, but time is not critical and films from several customers and different exposures will develop satisfactorily. The time over which development takes place, and the type of developer, affect the relationship between the density of silver in the developed image and the quantity of light. This study is called sensitometry and was pioneered by F Hurter & V C Driffield in the late 19th century.
Развивающими агентами являются метол (монометил-п-аминофенол-гемисульфат), фенидон (1-фенил-3-пиразолидинон), димезон (4,4-диметил-1-фенилпиразолидин-3-он) и гидрохинон (бензол-1,4-диол). Считается, что димезон более устойчив к окислению в растворе, чем фенидон А, но он менее доступен, чем фенидон А. Димезон также известен как фенидон В.
Developing agents. Popular developing agents are metol (monomethyl p aminophenol hemisulfate), phenidone (1 phenyl 3 pyrazolidinone), dimezone (4,4 dimethyl 1 phenylpyrazolidin 3 one) and hydroquinone (benzene 1,4 diol). Dimezone is thought to resist oxidation in solution better than Phenidone A, but it is not as available as Phenidone A. Dimezone is also known as Phenidone B.
Alkaline agent such as sodium carbonate, borax, or sodium hydroxide to create the appropriately high pH. Sodium sulfite to delay oxidation of the developing agents by atmospheric oxygen. Notable standard formulas include Eastman Kodak D 76 film developer, D 72 print developer, and D 96 motion picture negative developer. Hydroquinone is superadditive with metol, meaning that it acts to "recharge" the metol after it has been oxidised in the process of reducing silver in the emulsion. Sulfite in a developer not only acts to prevent aerial oxidation of the developing agents in solution, it also facilitates the regeneration of metol by hydroquinone (reducing compensation and adjacency effects) and in high enough concentrations acts as a silver halide solvent. The original lithographic developer contained formaldehyde (often added as paraformaldehyde powder) in a low sulfite/bisulfite solution. Most developers also contain small amounts of potassium bromide to modify and restrain the action of the developer The light sensitive layer or emulsion consists of silver halide crystals in a gelatin base. Two photons of light must be absorbed by one silver halide crystal to form a stable two atom silver metal crystal. The developer used generally will only reduce silver halide crystals that have an existing silver crystal. Faster exposure or lower light level films usually have larger grains because those images capture less light. Fine grain films, like Kodachrome, require more light to increase the chance that the halide crystal will absorb at least two quanta of light as they have a smaller cross sectional size. Therefore, silver halide crystal size is proportional to film speed. The metallic silver image has dark (black) appearance. Once the desired level of reduction is achieved the development process is halted by washing in a dilute acid and then the undeveloped silver halide is removed by dissolving it in a thiosulfate solution, a process called fixing. Most commercial film developers use a dual solution or "push" (pushes the films speed) development (compensating developer, like Diafine) procedure where the reducing agent e. g. hydroquinone solution soaks into and swells the gelatin then the film is introduced into the alkaline solution which activates (lowers reduction potential) of the developer. The areas with the most light exposure use up the tiny amount of developer in the gelatin and stop making silver crystal before the film at that point is totally opaque. The areas that received the least light continue to develop because they haven't used up their developer. There is less contrast, but time is not critical and films from several customers and different exposures will develop satisfactorily. The time over which development takes place, and the type of developer, affect the relationship between the density of silver in the developed image and the quantity of light. This study is called sensitometry and was pioneered by F Hurter & V C Driffield in the late 19th century.
Для создания соответствующего высокого pH используются щелочные агенты, такие как карбонат натрия, бура или гидроксид натрия. Сульфит натрия замедляет окисление развивающих агентов атмосферным кислородом. Известные стандартные формулы включают проявитель для плёнки Eastman Kodak D 76, проявитель для отпечатков D 72 и проявитель для киноплёнки D 96. Гидрохинон обладает супераддитивным эффектом с метолом, то есть он действует, "перезаряжая" метол после его окисления в процессе восстановления серебра в эмульсии. Сульфит в проявителе не только предотвращает окисление развивающих агентов на воздухе в растворе, но и способствует регенерации метола гидрохиноном (уменьшая эффекты компенсации и соседства), а в достаточно высоких концентрациях действует как растворитель галогенидов серебра. Исходный литографический проявитель содержал формальдегид (часто добавляемый в виде параформальдегидного порошка) в растворе с низким содержанием сульфита/бисульфита. Большинство проявителей также содержат небольшое количество бромида калия для модификации и сдерживания действия проявителя.
Developing agents. Popular developing agents are metol (monomethyl p aminophenol hemisulfate), phenidone (1 phenyl 3 pyrazolidinone), dimezone (4,4 dimethyl 1 phenylpyrazolidin 3 one) and hydroquinone (benzene 1,4 diol). Dimezone is thought to resist oxidation in solution better than Phenidone A, but it is not as available as Phenidone A. Dimezone is also known as Phenidone B.
Alkaline agent such as sodium carbonate, borax, or sodium hydroxide to create the appropriately high pH. Sodium sulfite to delay oxidation of the developing agents by atmospheric oxygen. Notable standard formulas include Eastman Kodak D 76 film developer, D 72 print developer, and D 96 motion picture negative developer. Hydroquinone is superadditive with metol, meaning that it acts to "recharge" the metol after it has been oxidised in the process of reducing silver in the emulsion. Sulfite in a developer not only acts to prevent aerial oxidation of the developing agents in solution, it also facilitates the regeneration of metol by hydroquinone (reducing compensation and adjacency effects) and in high enough concentrations acts as a silver halide solvent. The original lithographic developer contained formaldehyde (often added as paraformaldehyde powder) in a low sulfite/bisulfite solution. Most developers also contain small amounts of potassium bromide to modify and restrain the action of the developer The light sensitive layer or emulsion consists of silver halide crystals in a gelatin base. Two photons of light must be absorbed by one silver halide crystal to form a stable two atom silver metal crystal. The developer used generally will only reduce silver halide crystals that have an existing silver crystal. Faster exposure or lower light level films usually have larger grains because those images capture less light. Fine grain films, like Kodachrome, require more light to increase the chance that the halide crystal will absorb at least two quanta of light as they have a smaller cross sectional size. Therefore, silver halide crystal size is proportional to film speed. The metallic silver image has dark (black) appearance. Once the desired level of reduction is achieved the development process is halted by washing in a dilute acid and then the undeveloped silver halide is removed by dissolving it in a thiosulfate solution, a process called fixing. Most commercial film developers use a dual solution or "push" (pushes the films speed) development (compensating developer, like Diafine) procedure where the reducing agent e. g. hydroquinone solution soaks into and swells the gelatin then the film is introduced into the alkaline solution which activates (lowers reduction potential) of the developer. The areas with the most light exposure use up the tiny amount of developer in the gelatin and stop making silver crystal before the film at that point is totally opaque. The areas that received the least light continue to develop because they haven't used up their developer. There is less contrast, but time is not critical and films from several customers and different exposures will develop satisfactorily. The time over which development takes place, and the type of developer, affect the relationship between the density of silver in the developed image and the quantity of light. This study is called sensitometry and was pioneered by F Hurter & V C Driffield in the late 19th century.
Светочувствительный слой или эмульсия состоит из кристаллов галогенида серебра в желатиновой основе. Для образования стабильного двухатомного металлического кристалла серебра один кристалл галогенида серебра должен поглотить два фотона света. Используемый проявитель обычно восстанавливает только кристаллы галогенида серебра, в которых уже есть кристалл серебра. Плёнки с более высокой светочувствительностью или снятые при слабом освещении обычно имеют более крупные зерна, поскольку эти изображения захватывают меньше света. Мелкозернистые плёнки, такие как Kodachrome, требуют большего количества света, чтобы увеличить вероятность поглощения кристаллом галогенида по крайней мере двух квантов света, поскольку они имеют меньший размер поперечного сечения. Следовательно, размер кристаллов галогенида серебра пропорционален светочувствительности плёнки. Металлический серебряный образ имеет тёмный (чёрный) вид. После достижения желаемой степени восстановления процесс проявления останавливается промывкой в разбавленной кислоте, а затем не проявленный галогенид серебра удаляется путём растворения его в растворе тиосульфата – процесс, называемый фиксацией.
Developing agents. Popular developing agents are metol (monomethyl p aminophenol hemisulfate), phenidone (1 phenyl 3 pyrazolidinone), dimezone (4,4 dimethyl 1 phenylpyrazolidin 3 one) and hydroquinone (benzene 1,4 diol). Dimezone is thought to resist oxidation in solution better than Phenidone A, but it is not as available as Phenidone A. Dimezone is also known as Phenidone B.
Alkaline agent such as sodium carbonate, borax, or sodium hydroxide to create the appropriately high pH. Sodium sulfite to delay oxidation of the developing agents by atmospheric oxygen. Notable standard formulas include Eastman Kodak D 76 film developer, D 72 print developer, and D 96 motion picture negative developer. Hydroquinone is superadditive with metol, meaning that it acts to "recharge" the metol after it has been oxidised in the process of reducing silver in the emulsion. Sulfite in a developer not only acts to prevent aerial oxidation of the developing agents in solution, it also facilitates the regeneration of metol by hydroquinone (reducing compensation and adjacency effects) and in high enough concentrations acts as a silver halide solvent. The original lithographic developer contained formaldehyde (often added as paraformaldehyde powder) in a low sulfite/bisulfite solution. Most developers also contain small amounts of potassium bromide to modify and restrain the action of the developer The light sensitive layer or emulsion consists of silver halide crystals in a gelatin base. Two photons of light must be absorbed by one silver halide crystal to form a stable two atom silver metal crystal. The developer used generally will only reduce silver halide crystals that have an existing silver crystal. Faster exposure or lower light level films usually have larger grains because those images capture less light. Fine grain films, like Kodachrome, require more light to increase the chance that the halide crystal will absorb at least two quanta of light as they have a smaller cross sectional size. Therefore, silver halide crystal size is proportional to film speed. The metallic silver image has dark (black) appearance. Once the desired level of reduction is achieved the development process is halted by washing in a dilute acid and then the undeveloped silver halide is removed by dissolving it in a thiosulfate solution, a process called fixing. Most commercial film developers use a dual solution or "push" (pushes the films speed) development (compensating developer, like Diafine) procedure where the reducing agent e. g. hydroquinone solution soaks into and swells the gelatin then the film is introduced into the alkaline solution which activates (lowers reduction potential) of the developer. The areas with the most light exposure use up the tiny amount of developer in the gelatin and stop making silver crystal before the film at that point is totally opaque. The areas that received the least light continue to develop because they haven't used up their developer. There is less contrast, but time is not critical and films from several customers and different exposures will develop satisfactorily. The time over which development takes place, and the type of developer, affect the relationship between the density of silver in the developed image and the quantity of light. This study is called sensitometry and was pioneered by F Hurter & V C Driffield in the late 19th century.
Большинство коммерческих проявителей для плёнки используют двухкомпонентный раствор или процедуру "нагнетания" (увеличивает светочувствительность плёнки) проявления (компенсирующий проявитель, такой как Diafine), при которой восстановитель, например, раствор гидрохинона, впитывается и разбухает желатин, а затем плёнка погружается в щелочной раствор, который активирует (снижает потенциал восстановления) проявителя. Участки с наибольшим воздействием света расходуют небольшое количество проявителя в желатине и прекращают образование кристаллов серебра до того, как плёнка в этой точке станет полностью непрозрачной. Участки, получившие меньше света, продолжают проявляться, поскольку они не использовали весь проявитель. Контрастность снижается, но время не критично, и плёнки от нескольких клиентов и с разной экспозицией будут удовлетворительно проявляться. Время проявления и тип проявителя влияют на взаимосвязь между плотностью серебра в проявленном изображении и количеством света. Это исследование называется сенситометрией и было впервые проведено Ф. Хёртером и В. С. Дриффилдом в конце 19 века.
Developing agents. Popular developing agents are metol (monomethyl p aminophenol hemisulfate), phenidone (1 phenyl 3 pyrazolidinone), dimezone (4,4 dimethyl 1 phenylpyrazolidin 3 one) and hydroquinone (benzene 1,4 diol). Dimezone is thought to resist oxidation in solution better than Phenidone A, but it is not as available as Phenidone A. Dimezone is also known as Phenidone B.
Alkaline agent such as sodium carbonate, borax, or sodium hydroxide to create the appropriately high pH. Sodium sulfite to delay oxidation of the developing agents by atmospheric oxygen. Notable standard formulas include Eastman Kodak D 76 film developer, D 72 print developer, and D 96 motion picture negative developer. Hydroquinone is superadditive with metol, meaning that it acts to "recharge" the metol after it has been oxidised in the process of reducing silver in the emulsion. Sulfite in a developer not only acts to prevent aerial oxidation of the developing agents in solution, it also facilitates the regeneration of metol by hydroquinone (reducing compensation and adjacency effects) and in high enough concentrations acts as a silver halide solvent. The original lithographic developer contained formaldehyde (often added as paraformaldehyde powder) in a low sulfite/bisulfite solution. Most developers also contain small amounts of potassium bromide to modify and restrain the action of the developer The light sensitive layer or emulsion consists of silver halide crystals in a gelatin base. Two photons of light must be absorbed by one silver halide crystal to form a stable two atom silver metal crystal. The developer used generally will only reduce silver halide crystals that have an existing silver crystal. Faster exposure or lower light level films usually have larger grains because those images capture less light. Fine grain films, like Kodachrome, require more light to increase the chance that the halide crystal will absorb at least two quanta of light as they have a smaller cross sectional size. Therefore, silver halide crystal size is proportional to film speed. The metallic silver image has dark (black) appearance. Once the desired level of reduction is achieved the development process is halted by washing in a dilute acid and then the undeveloped silver halide is removed by dissolving it in a thiosulfate solution, a process called fixing. Most commercial film developers use a dual solution or "push" (pushes the films speed) development (compensating developer, like Diafine) procedure where the reducing agent e. g. hydroquinone solution soaks into and swells the gelatin then the film is introduced into the alkaline solution which activates (lowers reduction potential) of the developer. The areas with the most light exposure use up the tiny amount of developer in the gelatin and stop making silver crystal before the film at that point is totally opaque. The areas that received the least light continue to develop because they haven't used up their developer. There is less contrast, but time is not critical and films from several customers and different exposures will develop satisfactorily. The time over which development takes place, and the type of developer, affect the relationship between the density of silver in the developed image and the quantity of light. This study is called sensitometry and was pioneered by F Hurter & V C Driffield in the late 19th century.
Развитие цвета
В цветной и хромогенной черно-белой фотографии используется аналогичный процесс проявления, за исключением того, что восстановление серебра одновременно окисляет парафенилендиаминовый цветообразующий агент, который затем участвует в образовании красителей в эмульсии, реагируя с соответствующими проявителями. Здесь используются три различных процесса. Процесс C-41 применяется практически ко всем цветным негативным плёнкам, и в этом процессе красители в эмульсии реагируют с окисленным цветообразующим агентом в растворе проявителя, образуя видимые красители. Почти идентичный процесс затем используется для получения цветных отпечатков с плёнки. Используемые проявители являются производными парафенилендиамина. В цветной негативной плёнке существует три типа красителей. Это обычные циановые, пурпурные и жёлтые красители, а также маскирующий циановый краситель, формирующий пурпурный цвет, и маскирующий пурпурный краситель, формирующий жёлтый цвет. Они образуют соответственно нормальные циановый и пурпурный красители, но формируют оранжевую позитивную маску для цветокоррекции. Кроме того, существует третий тип красителя, называемый DIR (Developer Inhibitor Release) краситель. Этот краситель высвобождает сильный ингибитор во время образования красителя, что влияет на краевые эффекты и вызывает взаимодействие между слоями для повышения общего качества изображения.
Собственные методы
Процесс K 14 для пленок Kodachrome заключается в добавлении всех красителей в эмульсию в процессе проявки. Для обработки Kodachrome требовалось специальное оборудование. С 2010 года ни одна коммерческая организация в мире не осуществляет обработку пленок Kodachrome. В процессе создания цветных отпечатков, процессы Ilfochrome или Cibachrome используют материал для печати, содержащий красители, которые удаляются (выбеливаются) в нужных местах во время проявки. Химия, используемая в этих процессах, принципиально отличается от химии C41 (в ней применяются азокрасители, гораздо более устойчивые к выцветанию под воздействием солнечного света).