FIFTH CANADIAN CONFERENCE ON NONDESTRUCTIVE ... - IAEA

- 168 -
MAKING THE TRANSITION TO AUTOMATIC PROCESSING IN RADIOGRAPHIC NDT
W.E.J. UcKinnzij
E.I. Va Vont Ve. Ue.moan.is ê Co., Inc.
Wilmington, Ve.la.waie.
U.S.A.
MAKING THE TRANSITION TO AUTOMATIC PROCESSING IN RADIOGRAPHIC NDT
ABSTRACT
Automatic processing offers the potential for high volume, consistent quality
radiographie visible image formation. But, it is only partially automatic
and careful planning and execution are required to achieve the inherent
value. This paper discusses the advantages, and problems of automatic
processing and the procedures necessary in making the transition fran manual
to automatic processing.
INTRODUCTION
Radiographie latent image processing, whether manual or automatic, by hand or
by a machine, is a chemical reaction wherein the latent image is amplified
into the useful visible image. This is an oxidation/reduction reaction. The
developer is oxidized, releasing electrons which selectively attack exposed
silver halide crystals and reduces them to black metallic silver. This
reaction must be controlled by elements of time, temperature, and activity.
A radiographer chooses appropriate time, temperature, and activity levels.
In manual processing a person controls these values. In an automatic processor
the processor controls these functions. To many, this appears to be a
loss of control. Actually, by eliminating the human variable there is
increased consisfency and productivity. But, what if the technique is
incorrect? In manual it can be salvagedi This observation is a classic
dicotomy because yes the film can be saved, but should it be since obviously
the wrong technique was used. Allowing that processing, whether manual or
automatic, must neither overdevelop or underdevelop, why would it be manipulated
to save a poor technique? The answer is, in order to save an exposure
and this is referred to as "sight development". Its major failing is that,
it provides a way to mask the need for technique reform or control.