Chapter 11

1. Chapter 11 The X-ray Darkroom

2. General Darkroom Layout • If you are hand developing there should be a film handling area and a processing area to minimize the possibility of solutions contaminating the film and the intensifying screens. • If space is limited extreme caution should be taken.

3. General Darkroom Layout • When using an automatic processor a much smaller room can be used. • Today many x-ray rooms are set up so that the automatic processor is positioned in the x-ray room.

4. Lightproofing the Darkroom • Obviously the darkroom must be lightproof. • This is best tested by the use of dental film, half-covered, placed in various parts of the room for a period of time, three to five times the normal film handling time, and then developed.

5. Lightproofing the Darkroom • Any fog in the portion that was not covered indicates light leaks. The use of half-covered film eliminates film fogging from other sources. • A baffle entrance is more lightproof than a door (and permits better ventilation). • If you have your automatic processor in the x-ray room, this room, of course, will have to be light proof.

6. X-ray Proofing the Darkroom • The darkroom must be x-ray proof or radiation entering can fog the film being processed or, even more important, the larger amount of film being stored in the room. • This is more important when using non-screen film, however, screen film is also sensitive to x-ray.

7. X-ray Proofing the Darkroom • A leaded film bin will be needed if you are processing in the x-ray room. • The position of the x-ray unit is important (the primary beam should be focused away from the darkroom). • Additionally, the darkroom walls should be lead lined (see state specifications for specifics).

8. X-ray Proofing the Darkroom • The amount of lead needed is determined by room size, material of walls, types of x-rays, film/screens used, tube placement, placement of x-ray room within the building, and the x-ray machines capability.

9. X-ray Proofing the Darkroom • The adequacy of such protection can be checked by leaving a loaded cassette with a few coins or keys on top in the darkroom for a considerable number of exposures. Any exposure occurring can be attributed to x-ray leakage.

10. Darkroom Color • The color of the darkroom need not be a black or dull, dark color. • If the safelight is "safe" all the reflected light will be too. • Colors suggested are light green for use with a green safelight or beige for use with a red or yellow safelight.

11. Darkroom Cleanliness • The darkroom and all the equipment and accessories should be kept spotless. • Dust can cause artifacts on the film. • Chemical dust from spills can stain film and screens. • The solutions should be covered when not in use.

12. Darkroom Cleanliness • A contaminant or scratch on the cassette will also leave a reproducible artifact on the film until it is cleaned or replaced. • When changing solutions the tanks should be cleansed with Clorox before refilling. • Scouring powder should never be used as it leaves a gritty dust behind.

13. Darkroom Temperature • If you are hand developing, the darkroom temperature should be maintained as close to 68 degrees as is possible as should the developer. • In addition to influencing the temperature of the developer and fixer, excess heat can fog the film stored.

14. Darkroom Temperature • The film bin should be as far away from the heat source in the room. • Some means of controlling the temperature of the solutions should also be available.

15. Safelight Illumination • Wratten 6B (yellow) or Series 2 (red) can be used with a ten watt bulb and should not be directed at the film being handled. • The film should be at least 4 feet from the safelight at all times. • The length of time of exposure to the safelight is also a factor.

16. Safelight Illumination • Loading a cassette or putting a film onto a developing hanger should take a matter of seconds. • To test just how "safe" your safelight is, first make a radiograph in the usual manner.

17. Safelight Illumination • Then unload the cassette in the darkroom and cover half of it with black paper and expose the uncovered portion of the film to the safelight for a period usually used in film handling. • Develop the film for the normal length of time and examine it for any fogging in the uncovered portion.

18. Safelight Illumination • This is the same procedure in x-ray proofing. • The covering of half the film eliminates mistaking fogging from any other source for safelight fogging. • We should used exposed film because film exposed to x-rays and light from the intensifying screens is more sensitive than unexposed film.

19. Darkroom Ventilation • Noxious fumes may present with use of today's auto processors. Therefore, ventilation near the processor is needed. • Make sure that the ventilation system is lightproof.

20. Darkroom Set-up • When setting up a darkroom, preplan. • Installation of drains, a sink, and proper power sources should be considered initially as it is costly to add these necessities at a later date.

21. Darkroom Tidbits • For proper quality control (QC) you’ll need a sensitometer (controls the amount of each exposure & makes the same exposure in each given shot) & a densitometer (checks contrast, speed & fog). • You need to keep track of re-shoots & log why.