Operating Manual

Film types

and storage of films

Industrial X-ray films are produced by a limited number of manufacturers in an assortment

for use with or without intensifying screens and filters. The selection of a particular film

type not only depends on economics but in particular on the required, often prescribed,

image quality.

8.1 The Agfa assortment of film types

The films produced by Agfa are exclusively marketed world-wide by GE Inspection

Technologies. The assortment of industrial standard radiographic film comprises the follo-

wing types in sequence of increased speed and granularity : D2, D3, D4, D5, D7 and D8,

complemented with the very fast films F6 and F8.

The ultra-fine-grain D2-film is used in the radiography of very small components, when

optical magnification is applied to allow very fine details to be observed. D3 also exists as

D3 s.c. (single coating) as alternative for D2 and is extremely suitable for optical enlarge-

ments in case of very small components which require large magnification factors of the

image. Moreover this type of film is suitable for neutrography, see section 17.5. D8 is used

for the examination of big castings and steel reinforced concrete. D10 film is also produced

for exposure monitoring purposes, see section 19.6. Figures 1-8 and 2-8 show the rela-

tionship between film speed and image quality and film contrast respectively.

In addition to these graphs, figure 27-16 gives a graphical representation of relative image

quality as a function of relative dose and exposure time (film speed) for D-films and

computer-assisted CR and DR techniques.

Agfa has developed special intensifying screens specifically for use in combination with F6

and F8 films, see section 6.3. These so-called rapid cycle film screens are usually referred

to as RCF-screens indicated as Agfa NDT1200. F8 has the highest film speed. Depending

on quality requirements, F6 is mostly used for weld inspection on lay barges and on-stream

application (profile radiography); since it shortens examination time by a factor 10, see

section 6.3. This combination can also be used for (hand held) flash radiography to enable

lowest possible dose to make a quick but nevertheless suitable image.

Film and screens are available in a wide variety of sizes and packings. For example as sepa-

rate items to create a specific combination of film and screen or fully prepared for the job

in daylight packing including lead screens and evacuated (Vacupac) to guarantee the best

possible contact between film and screens. Films with screens are available on a roll

(Rollpac) to cut suitable lengths, or even precut at a specified length for large jobs which

require large numbers of identical film lengths, e.g. for girth weld inspection of long

distance pipelines. Last but not least films can be made in sizes on customer demand.

Fig. 1-8. Image quality versus film speed

The film speed is presented on a linear scale

Fig. 2-8. Contrast versus film speed

image quality - better

film speed

faster

image quality - better

film speed

faster