dark room equipments and entrance

By A.SHAJITHA B.sc RD Madras Medical College

DARK ROOM EQUIPMENTS AND ENTRANCE

A Dark room is a room, from which normal light is excluded.

It is made completely dark to allow the processing of light sensitive photographic materials.

What is Dark Room?

A Entrance to the dark room is light tight .

The Door should have lock in the knob that will keep people from entering the room while film is being processed.

FOUR TYPES OF ENTRANCEREVOLVING

SINGLEDOUBLE

MAZE

DARK ROOM ENTRANCE

DARK ROOM ENTRANCE:REVOLING DOOR

Most efficient but most expensive type.

Composed of two black cylinders.

The outer is fixed. Inner is the revolving door with only one opening.

REVOLVING DOOR

SINGLE DOOR

Simplest and cheapest type.

Weather striping around the door frame.

This type can cause accidental exposure of film to white light.

SINGLE DOOR

Used in single door system.To prevent accidental exposure of film to white light.

It locks the door while the film bin is open or while film being processed.

LOCKING MECHANISM

DOUBLE DOOR

Has two doors One leading in and other out with a short hallway in between.

One door cannot be opened unless the other is closed.

This type can cause trapping.

DOUBLE DOOR

MAZE

Has no doors.People can enter and exit at any moment.

Takes up too much building space.

MAZE

Processing TanksCassettesSafelightHangersAutomatic processor

DARK ROOM EQUIPMENTS

We use FOUR tanks in the processing procedure.

DEVELOPER RINZINGFIXERWASHING

PROCESSING TANKS

Universally used tank sizes:1 gallon2 gallon3 gallon 5 gallon10 gallon

1 GALLON=4.5 LITRES

Processing tanks are made up of stainless steel to avoid erosion.

The width of the tank may vary according to the capacity of the tank.

A radiographic film cassette is a rectangle or square plastic or metallic container used to hold x ray film (exposed or unexposed) and intensifying screens in close and uniform contact with one another.

CASSETTES

DIFFERENT CASSETTE SIZES 17 x 14 inches 15 x 12 14 x 14 12 x 12 12 x 10 10 x 8 12 x 6 (OPG)

1. Hold intensifying screen and protect them from damage.

2. Exclude all light from entering the cassette and fogging the film.

3. Maintain a close and uniform contact between the screen and film.

4. Exclude dust and dirt from the sensitive films.

5. Act as a medium from exposure up to further processing of film.

USES OF CASSETTES

A Safe light is a lamp which produces light in areas of the spectrum which will not affect photographic materials like film and photographic paper.

SAFELIGHT

AMBER –BLUE LIGHT SENSITIVE FILM(400-450nm)

RED—GREEN LIGHT SENSITIVE FILM ORTHOCHROMATIC(500-550nm)

TOTAL DARKNESS FOR PANCHROMATIC FILM (1200nm)

DRY BENCH

15 W

AT LEAST 2 FEET FROM THE FILM TRAY

There are two safe lights in the dark room.

One is on the wet bench Other one is on the dry bench

Safelights can be direct or indirect Should give sufficient light to facilitate work once your eyes have adjusted

Must be at least 1.2m above work area

Safelights are not completely safe over prolonged exposure so make sure you work quickly & efficiently to avoid fogging your film!!!!

Uses of safelightFor loading and unloading of cassettes

For processing procedure

HANGERS

A film hanger is a instrument or device for holding radiographic film during processing procedure.

Available in various sizes.

Made up of stainless steel.

Three types of hangersCLIP TYPE CHANNEL TYPESPRING TYPE

Automatic film processor is a equipment.

It used for the fast and efficient method in the film.

In is mechanically transferred from the developer to the fixer.

And is washed and finally dried.

AUTOMATIC PROCESSOR

Automatic processor containsDEVELOPERFIXERWASHING DRYER

It contains rollers instead of rinsing in manual processing.

Advantages of automatic processor

Dry to dry systemNo work load like manual processing

It maintains the time and temperature of the processing procedure.

Automatic processor timingsDeveloper -26 secFixer – 15 sec Washing – 15 sec Drier - 24 secTravelling – 10 secTotal – 90 sec

Hatches are designed to transfer film cassettes to and from the dark room without radiation light entering

It consist of metallic structures with a lead lining to provide x ray shielding.

They are typically wall mounted and include automatic interlocks that close one door when other is opened.

HATCHES

It is also used for the temporary storage of loaded cassettes.

Film racks are used to keep the film boxes.

It is very important that film boxes are always kept vertically.

Not horizontally.When we keep horizontally pressure on the film boxes may produce artifacts.

FILM RACK