Dark room processing in X-ray
There are five types of process –
1 . DEVELOPING
1. DEVELOPING – The main function is to reduce the exposed silver halide to black metallic silver.
• Hydroquinone & Metol (Reducing agents/ Developing agents)- It produces grey and black shade at an early stage of development of the film.
• Sodium carbonate/ Sodium hydroxide ( Activator ) – activates developer agents ( soften the gelatin of the emulsion).
• Potassium Bromide/Potassium Iodide ( Restrainer ) – Antifoging agents save from chemical fog.
• Sodium Sulphite ( Preservative)- Prevent rapid oxidation of the developing agents.
• Water (Solvent) – It dissolves Chemicals
Developing Time – 5 Minutes
Developing Temperature – ( 20- 22°C)(68-72°F)
2. RINSING – Use Circulating water at least 30 sec to remove all traces of the developer from the film.
3. FIXING / Fixation – Main function is to remove all unexposed, undeveloped silver halide from the film emulsion. ( Silver halide – silver bromide / silver iodide)
• Sodium thiosulphate/ Amonium thiosulphate ( Fixing agent) – Clear the film by dissolving out the undeveloped silver halides, leaving the metallic silver in the exposed areas of the film.
• Sodium Sulphite ( Preservative) – protect the fixing agents from decomposition and clear the film.
• Chrome Alam / Potassium Alam ( Hardener ) – Protect the film against scratches, and harden the gelatin of the emulsion.
• Sulphuric acid / Acetic acid ( Acidifier/ acid ) – Its main purpose is to neutralize the alkali still remaining in the film and provide an optimum medium for the fixer & hardener.
• Water ( Solvent)- It dissolves chemicals
Fixing Time – 3-4 Minutes
Fixing Temperature – 18-24°C
4. WASHING – Washing in running water for 20 minutes at 20° C / 68° F.
5. DRYING – Hot air dryer cabinets are useful / Open air ( Film must be hanging in dust free area)
Drying temperature – 35°C/ 75°F.
Darkroom equipment –
The dark room should contain following –
√• Color Safe light less than 15 watt
√• Visible light source ( tube light)
√• Working table where to load/unload cassettes
√• Processing tanks
√• Thermometer and Stop clock
√• Storage facility for unexposed film
√• Appropriate Ventilation
√• The dark room should have three types of illumination.
Question – Describe the composition of developing and fixing solution and their function.
Answer– Developing solution composition –
1. Reducing/ Developing agents- Hydroquinone and Metol .
2. Activater- Sodium carbonate/ Sodium hydroxide.
3.Restrainer – Potassium Bromide / Potassium Iodide .
4. Preservative – Sodium Sulphite.
5. Solvent – Water
The developing solution’s main function is to reduce the exposed silver halide to black metallic silver.
Fixing solution composition –
1. Fixing agents – Sodium thiosulphate/ Ammonium thiosulphate.
2. Preservative – Sodium Sulphite
3. Hardner – Chrome Alam / Potassium Alam
4.Acidifier / Acid – Sulphuric acid / Acetic acid
5. Solvent – Water
The fixing solution’s main function is to remove all unexposed, undeveloped silver halide from the film emulsion and clear the film.
Note – ( Silver halide is mainly Silver Bromide / Silver Iodide).
I hope you like this post – Darkroom processing in X-ray.