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Chemical mixing formulae
Up until about thirty years ago photo- graphers prepared all their processing solutions by weighing out and mixing the basic chemicals . Today this is done in factories , and most processing solutions are bought as liquids ready for dilution . If you have time you can still save considerable expense by weighing and mixing up your own solutions , provided you can obtain the raw chemicals . Some photographic solu- tions certain bleaches for instance = are not available ready - made , and so have to be prepared . The only equipment you need is a pair of scales , a set of weights capable of measuring as little as half a gram , and , if possible , a small laboratory chemical mixer . Never touch chemicals directly with your hands , always wear rubber gloves . Most black and white photographic chemicals are fairly harmless but you should take special care with strong acids or alkalis such as sodium hydroxide .
When mixing an acid , you should always add it to a solution , never the reverse . Measure and mix chemicals in a well ventilated room , and avoid inhaling fumes - particularly from acids , fixers , and toners . Keep all chemicals well out of the reach of children and do not store solutions in bottles which look like drink containers .
-------------------
Sepia toner
-------------------
Bleach
20 gm Pot . ferricyanide ( c ) 20 gm Pot . bromide Water made up to 1 liter
Toner
20 gms Sodium sulfide Water made up to 1 liter
-------------------
lodine bleacher
15 gm
Pot . iodide ( c ) lodine
4 gm
Water made up to 1 liter
-------------------
Stop bath
Paper
15 ml Acetic acid ( glacial ) , or citric acid made up to 1 liter
Films
30 ml Acetic acid ( glacial ) , or citric acid made up to 1 liter
-------------------
Mixing from formulae
Weigh out correct amounts of all the chemicals listed in the formula , as explained below . You can use either letter scales or the chemical balance as shown . ( Balances are more accurate for small quantities but you have to weigh larger amounts of chemicals in several lots . ) The chemicals in each for- mula shown right are listed in order of mixing . Dissolve the chemicals one after the other into slightly less than the final volume of water , and then add water to make up the final volume .
Most of the chemicals shown are
anhydrous or monohydrate fine powders which dissolve fairly readily in water of about 70 ° F ( 20 ° C ) . Some may be crystals , which dissolve more easily in warmer water at around 100 ° F ( 38 ° C ) . Crystals lower the tem- perature of the solution as they dissolve . Make sure one chemical has completely dissolved before adding the next . Give time for your solution to settle and regain normal temperature before use . Keep it stored in a sealed bottle most solutions deteriorate when left exposed to the air .
-------------------
Ferricyanide ( Farmers ) Reducer
-------------------
Solution A
8 gm Pot . ferricyanide ( c ) Water made up to 1 liter
Solution B.
200 gm Sodium thiosulfate Water
made up to 1 liter
Mix equal quantities of each just before use
-------------------
Chromium intensifier
-------------------
9 gm
Pot . dichromate ( c )
6 ml
Hydrochloric acid Water made up to 1 liter
After bleaching re- blacken in normal print developer
-------------------
Tray and tank cleaner
-------------------
25 gm
Pot . permanganate ( c )
5 ml
Sulfuric acid ( concentrated ) Water made up to 1 liter
Leave in the dish for several minutes , then rinse , clean with fixer , and wash out
------------------
Developer ingredients ( gm )
------------------
Metol
Hydroquinone
Sodium sulfite ( anh )
Pot . Sodium hydroxide
Sodium carbonate ( anh )
Borax
Sodium Metaborate
Pot . Bromide
Water made up to
------------------
Fixer ingredients ( gm )
------------------
Sodium thiosulfate ( c )
Ammonium thiosulfate
Sodium sulfite ( anh )
Acetic acid ( glacial )
Boric acid ( c )
Pot . Alum ( c )
Water made up to
Pot . potassium
------------------
Weighing and mixing chemicals
1. Place two equal size pieces of paper , one in each pan , to hold the chemicals . Never pour the chemicals directly on to the balance pan .
2. Put the required weights on one pan . Gently tip the chemica on to the paper in the other pan until the two pans balance . Re- move the chemical on its paper ; replace with new paper .
3. Use a jug large enough to hold the final quantity of solu- tion . Pour in two thirds of the water , then slowly pour in and mix each chemical in sequence stirring continuously .
4. Add the remaining water to the mixture and pour the solu- tion into a storage bottle . Seal and label .
Chemical mixing formulae
Up until about thirty years ago photo- graphers prepared all their processing solutions by weighing out and mixing the basic chemicals . Today this is done in factories , and most processing solutions are bought as liquids ready for dilution . If you have time you can still save considerable expense by weighing and mixing up your own solutions , provided you can obtain the raw chemicals . Some photographic solu- tions certain bleaches for instance = are not available ready - made , and so have to be prepared . The only equipment you need is a pair of scales , a set of weights capable of measuring as little as half a gram , and , if possible , a small laboratory chemical mixer . Never touch chemicals directly with your hands , always wear rubber gloves . Most black and white photographic chemicals are fairly harmless but you should take special care with strong acids or alkalis such as sodium hydroxide .
When mixing an acid , you should always add it to a solution , never the reverse . Measure and mix chemicals in a well ventilated room , and avoid inhaling fumes - particularly from acids , fixers , and toners . Keep all chemicals well out of the reach of children and do not store solutions in bottles which look like drink containers .
-------------------
Sepia toner
-------------------
Bleach
20 gm Pot . ferricyanide ( c ) 20 gm Pot . bromide Water made up to 1 liter
Toner
20 gms Sodium sulfide Water made up to 1 liter
-------------------
lodine bleacher
15 gm
Pot . iodide ( c ) lodine
4 gm
Water made up to 1 liter
-------------------
Stop bath
Paper
15 ml Acetic acid ( glacial ) , or citric acid made up to 1 liter
Films
30 ml Acetic acid ( glacial ) , or citric acid made up to 1 liter
-------------------
Mixing from formulae
Weigh out correct amounts of all the chemicals listed in the formula , as explained below . You can use either letter scales or the chemical balance as shown . ( Balances are more accurate for small quantities but you have to weigh larger amounts of chemicals in several lots . ) The chemicals in each for- mula shown right are listed in order of mixing . Dissolve the chemicals one after the other into slightly less than the final volume of water , and then add water to make up the final volume .
Most of the chemicals shown are
anhydrous or monohydrate fine powders which dissolve fairly readily in water of about 70 ° F ( 20 ° C ) . Some may be crystals , which dissolve more easily in warmer water at around 100 ° F ( 38 ° C ) . Crystals lower the tem- perature of the solution as they dissolve . Make sure one chemical has completely dissolved before adding the next . Give time for your solution to settle and regain normal temperature before use . Keep it stored in a sealed bottle most solutions deteriorate when left exposed to the air .
-------------------
Ferricyanide ( Farmers ) Reducer
-------------------
Solution A
8 gm Pot . ferricyanide ( c ) Water made up to 1 liter
Solution B.
200 gm Sodium thiosulfate Water
made up to 1 liter
Mix equal quantities of each just before use
-------------------
Chromium intensifier
-------------------
9 gm
Pot . dichromate ( c )
6 ml
Hydrochloric acid Water made up to 1 liter
After bleaching re- blacken in normal print developer
-------------------
Tray and tank cleaner
-------------------
25 gm
Pot . permanganate ( c )
5 ml
Sulfuric acid ( concentrated ) Water made up to 1 liter
Leave in the dish for several minutes , then rinse , clean with fixer , and wash out
------------------
Developer ingredients ( gm )
------------------
Metol
Hydroquinone
Sodium sulfite ( anh )
Pot . Sodium hydroxide
Sodium carbonate ( anh )
Borax
Sodium Metaborate
Pot . Bromide
Water made up to
------------------
Fixer ingredients ( gm )
------------------
Sodium thiosulfate ( c )
Ammonium thiosulfate
Sodium sulfite ( anh )
Acetic acid ( glacial )
Boric acid ( c )
Pot . Alum ( c )
Water made up to
Pot . potassium
------------------
Weighing and mixing chemicals
1. Place two equal size pieces of paper , one in each pan , to hold the chemicals . Never pour the chemicals directly on to the balance pan .
2. Put the required weights on one pan . Gently tip the chemica on to the paper in the other pan until the two pans balance . Re- move the chemical on its paper ; replace with new paper .
3. Use a jug large enough to hold the final quantity of solu- tion . Pour in two thirds of the water , then slowly pour in and mix each chemical in sequence stirring continuously .
4. Add the remaining water to the mixture and pour the solu- tion into a storage bottle . Seal and label .
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