The fog correction of photographic densities

NOTES

FROM

THE

RESEARCH

EASTMAN THE

FOG

KODAK

CORRECTION

OF

COMPANY.”

PHOTOGRAPHIC

SENSITOMETRIC

A

LABORATORY,

DENSITIES.’

STUDI-.

By H. A. Pritchard. TlIE:

fo g correction,

Wilsey

the mass

of silver

of

unaffected

silver

developing

by exposure,

unless

the fog is small,

work,

experimental

study more

has

methods

fog reached The area

several effect.

been

density a value

to give Bloch

functions

completely

that

to the mass factors

which,

In the present

were

obtained

times

developed.

sensitometric

by a

after

image

These

data than

gave

previous

measuring

fog

in a small

of each density

indicated

was practically

(Elon-hydroquinone development, less than

exposures,

development

S-ray

it was

found

maximum was

negligible

* Communicated 1(hnmunication

of with

formula). to develop

fog density,

image

how-

density.

effect observed

found

protected

the influence

possible

The maximum

the reversal times

that

to remain

development of all the silver in the film. The large variations in photometric equivalent under extreme conditions to contribute considerably of the Wilsey

before

of fog correction

results.

of

in the film as fog.

In the lower

developed

method

on development

was considerably

film at long

completely

the Wilsey

satisfactory

used

By prolonged all the silver

was practically of 0.5,

method

products

the developer

ever.

omits

sets of corrected

in the centre

reaction

assumption

of fog correction.

If image appeared

the

of fog at long development

practically

consistent

on

have an appreciable

fo, c correction

of the growth

density

based

as fog is proportional

on positive at complete are believed to the failure

fog correction.

by the Director. No. JIO from the Kodak Research lished in Phot. J., 67, 4.47. 1927.

Laboratories

and pub‘35