Photographic speed

Silver on Diai Plates. Sdvet hahde has high photographic speed and a highly developed sensitizing and stabilizing technology. The principal problem... 

In recent years visible photoinitiators for the formation of polymers via a radical chain reaction have also been developed. These absorb light which is blue, green, or red and also cause the polymerization of polyolacrylates, in some instances, such as encapsulated systems, with speed which is near photographic. Some of these photoinitiators provide the photochemical backbone of the nonsilver, near-photographic speed, imaging processes such as the Cycolor processes invented by the Mead Corporation. Cycolor initiators are cyanine dye, borate ion salts (4)—so-called ( +, —) ion pair... 

A desirable property of a photothermographic system is the ability to amplify the light exposure during the thermal process, thereby increasing the photographic speed.195 Thus the product of the photochemical step should catalyze the thermal reaction. 

The principles of semiconductor photophysics used in silver halide imaging can be applied to other semiconductors. However, the photographic speed obtained with silver systems is usually lost, since it arises not from the act of creating the latent image, but during the development step in which external electrons are supplied to the system to reduce silver ions to silver metal. Nevertheless, several interesting systems have been reported. 

Photographic Speed Determination of the Amorphous and l.c.-p-methoxvcinnamate Polymers... 

The three most important parameters which must be controlled when comparing the photographic speeds of similar negative-woiking-light-sensitive polymers are the following ... 

The formulation used to cast the films in order to determine the photographic speed of the p-methoxycinnamate polymers was the following ... 

Table I shows the molecular weights and the relative photographic speed results of the amorphous p-methoxycinnamate polymer films. The difference in the photographic speed between polymers X and XIA, XIB could be attributed to the difference in the backbone configuration and the effect it has on the orientation of the cinnamate chromophore as well as the M.W. difference.

Table II shows the relative photographic speed results of the anisotropic-l.c. p-methoxycinna-mate polymer films. The photographic speed of the l.c. p-methoxycinnamate polymers exceeded our most optimistic expectations. It was necessary to handle films of polymers IX-3, IX-4, and IX-5 under safe-light conditions to avoid premature fogging. Polymer IX-5 (Table II) had a molecular weight 6X that of the PVA cinnamate control, X, but was 83X faster. The molecular weight difference certainly accounted for some of this increased speed, but obviously could not account for all of it.

Figure 7. Relative photographic speed as a function of absolute MW for the l.c. polymer IX.

DQE is an overall figure of merit for an imaging device or process, which incorporates photographic speed, contrast (gamma), and granularity. DQE is an embodiment of the speed-image quality trade-off. It is defined as... 

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