Dark room processing in X-ray 

   Dark room processing in X-ray 

There are five types of process – 

1 . DEVELOPING 

2.  RINSING 

3.  FIXING 

4.  WASHING 

5.  DRYING 

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 

√• Dryer 

å Storage facility for unexposed film

√• Appropriate Ventilation 

å 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.