Copyright
John Adolphus Flemer.

An elementary treatise on phototopographic methods and instruments, including a concise review of executed phototopographic surveys and of publicatins on this subject online

. (page 28 of 33)
Online LibraryJohn Adolphus FlemerAn elementary treatise on phototopographic methods and instruments, including a concise review of executed phototopographic surveys and of publicatins on this subject → online text (page 28 of 33)
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may be avoided by using a " hydrometer " (the single-degree
hydrometer generally used for testing silver solutions is best)
for testing the concentration of the solutions, as dried or crys-
tallized chemicals may then be used indiscriminately.

Stock solutions are best put up in limited quantities, as most
photo-chemical solutions deteriorate with age. It may be noted
here that chemical action may be increased considerably by con-
ducting development under relatively high temperatures, and
decreased when working under a temperature lower than 70,
the latter being generally recommended for the best results.

Nearly all developing compounds are composed of two parts,
the developing agent proper and the alkaline solution. Among
the developing agents more generally in use we have: Ferrous
oxalate, pyrogallic acid, hydrochinon, eikonogen, metol, rodinal,
their various combinations, and many others, increasing in num-
ber from year to year. They differ in speed, action, keeping
qualities, density imparted to the negative, latitude permissible



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 351

in the exposure of the plate, etc. After having become familiar
with the action of any one developer it is recommended to adhere
to its use to insure uniformity in the resulting negatives.

If, in a given developer, the developing agent be used in
excess of the correct proportion, too great a contrast between
the lights and shadows will result; the development will not be
under control, it will progress too fast. An insufficient amount
of the developing agent will produce a negative deficient in strength
and lacking the qualities essential for good printing. The gen-
eral development will be slow with the concomitant danger of
" frilling," which is the separation of the film from the edges
of the glass plate.

The alkaline ingredients of the developing- solution, prin-
cipally carbonates of sodium (" sal soda ") and potassium, bicar-
bonate of soda, and sulphite of soda, serve to open the pores of
the gelatino-bromide of silver emulsion, permitting a free entrance
of the developing agent into the upper layers of the softened
plate film, thus producing a more prompt and effective action
on the embedded particles of the silver haloids. An excess of
the alkaline solution tends to produce a dense negative, imparts
a tendency to fog the plate, and often converts the film of the
latter into a granular condition.

The progress of development will be materially retarded if
an insufficient quantity of the alkaline solution be used. Bicar-
bonate of soda, being less active than carbonate of soda and
carbonate of potassium, is often used, in combination with sul-
phite of sodium, for developing thinly coated plates to reduce
their tendency toward fog formation and to prevent injury to
the film. The alkaline solutions are preferably kept in hermet-
ically closed bottles to prevent decomposition, which would soon
take place on exposure to the air. Old alkaline solutions, or such
containing impure sulphite of sodium, are apt to produce yellow
stains on the negative and feshly prepared solutions of pure
sulphite of sodium should be used whenever possible.

All chemicals for photographic use should be pure, and it is



352 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

recommended to purchase those especially manufactured for
photochemical purposes. Some manufacturers of compressed
pharmaceutical preparations have extended the tabloid system
to photographic preparations. The advantages of the tabloid
form to the traveller, explorer, and to the novice in the practice
of photography are apparent. Tabloids when prepared by dry
compression do not readily decompose; they retain in their full-
est energy the qualities of the various ingredients of which they
are compounded, and they have reliability, uniformity, and
portability in their favor.

A. Water and Water Tests.

The water used in photographic operations should be dis-
tilled or pure and free from foreign matter. By reason of its
great dissolving power, ordinary water, in the absence of the
distilled article, should be boiled for some time and then allowed
to cool before decanting it for making photochemical solu-
tions. The following simple tests may be applied to discover
the presence of iron, magnesia, lime, etc., in ordinary water:
For Iron: The addition of an infusion of nutgalls to water
will show the presence of iron by imparting a grayish
color to the mixture. If the liquid turns blue, after the
addition of a pinch of prussiate of potash, the presence
of iron is unmistakable.

For Magnesia: Reduce a certain amount of water by boiling

to J /2oth of its original weight, then dissolve a few

grains of neutral carbonate of ammonia in this liquid.

If a whitish precipitate is formed, after the addition of a

few drops of phosphate of soda, magnesia will be present.

For Lime: If two drops of a concentrated solution of oxalic

acid be added to a glass of water, the latter will contain lime

if a milky appearance be thus produced.

For Alkalies: Water that will change red litmus paper, on

immersion in the same, to blue may be considered alkaline.



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 353

For Organic Water: Water becoming turbid, after the addi-
tion of one tablespoonful of tannin solution (i part
tannin, 4 parts water, and i part alcohol) to a tumblerful,
will contain organic matter. Such water is unfit for drink-
ing purposes, particularly if the impurities are of animal
origin.

For Hardness: If no change be noted after adding a few
drops of a solution of good soap in alcohol the water is
soft; if it becomes milky in appearance it may be con-
sidered hard.

For Carbonic Acid: To half a tumblerful of water add an
equal amount of lime-water; if carbonic acid be present
a precipitate will be formed and the addition of muriatic
acid will cause effervescence.

B. Developers.

There is a distinct relation between the intensity of the light
that has acted upon the sensitized emulsion coating of a plate
and the actual amount of silver that is deposited upon the plate
under the action of the developer and which defines the density
of the negative. The laws which control the combined effects
of light and developer upon a photographic plate have been
studied by many photochemists. The results of the researches
made by F. Hurter and V. C. Driffield in England are generally
accepted as representing the best discussion on the subject.
Capt. E. Deville, in his work on " Photographic Surveying ",
gives an abstract of the principal papers published by Messrs.
Hurter and Driffield, with which every photographer should
familiarize himself if he is desirous to obtain a knowledge of
the laws of correct exposure and development.

i. DEVELOPING WITH FERROUS OXALATE.

Ferrous oxalate is the best developing agent for phototopo-
graphic purposes if the exposed plates are packed away in the
field to be developed at some later period. For the develop-



354 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

ment of test-plates in the field where the means of transpor-
tation are limited, and where, owing to the numerous other duties
to be performed, dark-room operations must be reduced to a mini-
mum, developers in the form of dry powders or tabloids will
generally be preferred.

Good results are obtainable with the iron developer, even
after the exposed plate has been stored away for a long time,
before the actual development of the same is undertaken. Fer-
rous oxalate may furthermore be recommended, because it affects
only those particles of the silver haloids that had previously
been acted upon by solar light, and because the final metallic
silver deposit on the plate shows great uniformity in color. For
these reasons negatives developed with the iron developer are
particularly well suited for making enlargements by " optical
projection."

The products resulting from the oxidation of ferrous oxalate,
after an exposed plate has been in the developer a short while,
exercise a restraining influence over the progress of development,
without, however, stopping it altogether. The plate continues
to gain density under the prolonged action of the developer,
but the energy of the latter is held under control and the progress
of development becomes more and more retarded under the
gradual advance of the process of oxidation. The details of
the image slowly become visible on the plate under the restrained
action of the developer, gradually gaining strength and density,
and at full development, when the plate is removed from this
bath, the plate coating will have undergone a permanent change,
inasmuch as particles of the silver haloid that have not been
acted upon by the solar rays practically will have remained
unchanged, while those that had been acted upon will become
reduced to free silver. The final image on the negative is formed
by a more or less gradated series of tones, conditioned by the
various thicknesses of metallic black silver deposits that have been
formed on the different parts of the plate.

For the development of the plates obtained in connection



DEVELOPMENT OF ORTHOCHROMATIC DRY- PLATES. 355

with the Canadian surveys, Captain E. Deville uses freshly pre-
pared ferrous oxalate compounded in two stock solutions after
the following formulas:

A.

Metric Weight. Apothecaries' Weight.

30 grammes. . . Oxalate of potash i oz.

90 c.c Distilled water (hot) 3 oz.

i gramme. . . . Bromide of potassium 15 grains

c.c Acetic acid 10 minims

B.

30 grammes. . . Sulphate of iron i oz.

60 c.c Distilled water (hot) 2 oz.

J c.c Acetic acid 2 minims

These stock solutions, A and B, keep well if bottled sepa-
rately; they should be mixed for immediate use only. For the
normal developer take to each ounce of solution A two drachms
of solution B. The plates are developed, a dozen at a time, in
grooved hard-rubber boxes, in which they are placed hi an upright
position.

The formulae for Dr. Eder's ferrous oxalate developing-bath
are as follows:

A.

Metric Weight. Apothecaries' Weight.

200 grammes . . Neutral oxalate of potassium 6 oz.

800 c.c Distilled water (hot) 26| oz.

This stock solution should be acidulated with oxalic acid,
adding one gramme for every 30 c.c. of the solution.

B.

Metric Weight. Apothecaries' Weight.

100 grammes. . Protosulphate of iron (crystals) 3$ oz.

300 c.c Distilled water (hot) 10 oz.

$ c.c Sulphuric acid 5 minims

Mix hi the order given, adding the acid last. These solutions
are good keepers when bottled separately, and they should be
mixed (dold) for immediate use only. For the normal de-



356 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

veloper and for correctly timed exposures take volumes of
A and i volume of B and mix in a graduate.



(a) Restraining the Ferrous Oxalate Development.
C.

Metric Weight. Apothecaries' Weight.

10 grammes. . . Bromide of potassium 2^ drachms

100 c.c Distilled water oz.



By adding a few drops of this solution C, termed a re-
strainer, to the normal iron developer, given above, the
development of the latent image will be kept under control. A
moderate overexposure of a plate may thus be neutralized by
adding from five to ten drops of solution C to the ferrous
oxalate developer, which will check the general progress of develop-
ment sufficiently to impart density to the plate and to allow the
details to appear in the high lights before the shadows become
overdeveloped.

The simultaneous appearance of lights and shadows on the
plate (" the flashing-up " of the image) immersed in the develop-
ing-bath would be indicative of overexposure, and the plate
should be immediately removed from the developing-tray, be
well rinsed in soft running water and be subjected to one of the
following means of " retarding " development:

1. Reducing the sulphate of iron solution (against the " nor-

mal " amount of oxalate of potash solution);

2. Reducing the temperature of the "normal developer";

3. Increasing the bromide of potassium (or other bromide

salt used) ;

For the development of overexposed plates it is advisable
to withhold about 30 c.c. (i oz.) of solution B in a separate
graduate and add from 2 to 4 c.c. (30 to 60 minims) of solu-
tion C gradually pouring enough of this mixture to the de-
veloper in the tray to produce the desired density in the plate.
Additions to the developer are preferably made after the latter



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 357

has been poured off the plate into a pouring vessel, flooding the
plate with the modified developer homogeneously mixed.

4. Diluting the " normal developer " with water;

5. Using an old (already used) developer.

(b) Accelerating the Ferrous Oxalate Development.

The application of so-called " accelerators " overcomes, in
a measure, the effects of underexposure. They may also bs of
value when developing plates representing subjects of great
contrasts, or in all cases where the normal developer would
produce too harsh and too dense a negative. The following
means for accelerating development may be employed.

1. Increasing the sulphate of iron solution (against the

"normal" amount of oxalate of potash solution);

2. Increasing the temperature of the "normal developer";

3. Using a freshly prepared and slightly concentrated solution

of the " normal developer ";

4. Adding a very little hyposulphite of sodium to the " normal

developer."

About three ounces of a developer, when mixed ready for
use, will suffice for the development of a 4X5, and four ounces
will be required for a 5X8 in. plate. When several plates are
to be developed it is best to prepare a larger quantity of the nor-
mal developing mixture at one time and develop a dozen plates
at once.

After the proper stage in the development has been reached,
the plate should be well rinsed in clear running water, then to
be placed in the following so-called " clearing solution," which
serves to prevent the precipitation of iron from the developer
into the upper layer of the plate film.

D.

CLEARING SOLUTION.
Metric Weight. Apothecaries' Weight.

150 c.c Saturated solution of alum 5 oz.

4 c.c Citric acid ' I drachm

150 c.c Distilled water S oz.



358 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

The negative is submerged in this bath from three to five
minutes, after which it is again rinsed in clear running water to
remove any deposit that may still adhere to the film surface,
to be finally placed in the " fixing-bath."

2. PYRO DEVELOPER.
A good " pyro " developer may be made in two solutions:

A.

ALKALINE SOLUTION.

Metric Weight. Apothecaries' Weight.
360 c.c Distilled water 60 oz.

30 c.c Carbonate of sodium (crystals) 5 oz.

60 c.c. Sulphite of sodium (crystals) 10 oz.

To prepare this solution with the "hydrometer," mix equal
parts of:

Carbonate of sodium solution, testing 40 degrees

Sulphite of sodium solution, testing 80 degrees

B.
PYRO SOLUTION.

Metric Weight. Apothecaries' Weight.

4 c.c Sulphite of sodium (crystals) i drachm

180 c.c Distilled water 6 oz.

After the sulphite of sodium has been dissolved in the 6 oz.
of water, add acetic acid to this solution until the liquid turns
blue litmus paper red, then add:

Metric Weight. Apothecaries' Weight.
30 c.c Pyrogallic acid i oz.

For the " normal developer " mix:

Metric Weight. Apothecaries' Weight.

4 c.c of B (pyro solution) i drachm

60 c.c. of A (alkaline solution) 2 oz.

For winter use, dilute this with 60 c.c. (2 oz.) of tepid c._s-
tilled water, whereas for summer use, dilute with 90 to 150 c.c.
(3 to 5 oz.) of cold distilled water.



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 359

Both solutions should be kept in well-stoppered bottles. If
the negatives show yellow stain a new solution A should be made
or a freshly prepared sulphite of sodium should be used.

A smaller quantity of sulphite of sodium in solution A will
produce a warmer tone, a larger quantity a grayish-blue to bluish-
black tone. An increase of A in the normal developer mixture
may bring out detail in an underexposed negative. If the high
lights in the negative are flat more of the pyro solution (B) may
be used, if they are too intense less may be used.

If too little of solution B be used the alkali will be in excess
and a foggy negative may be the result.

Pyrogallic acid, being a strong poison, should be carefully
handled, clearly labeled, and securely stored.

3. METOL DEVELOPER

may be made in either one or two solutions, both keeping well.
The two-solution developer, however, is preferable, as it not only
gives a better control over the progress of development but it
also gives the means for developing overexposed plates by
adding a little of solution B to the " normal developer," or by
using solution A alone (diluted) if the plate was greatly over-
exposed.

A,

Metric Weight. Apothecaries' Weight.

1000 c.c Distilled water 10 oz.

15 grammes.. . . Metol 75 grains

120 grammes.. . . Sulphite of sodium (crystals) i^ oz.

Dissolve the metol in water before adding the sulphite of
sodium.

B.

Metric Weight. Apothecaries' Weight.

1000 c.c Distilled water 10 oz.

150 grammes. . Carbonate of soda (crystals) 1.75 oz.

i. 5 grammes. . Bromide of potassium 8 grains



360 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

For the normal developer take:

Solution A, i volume

B, i "
Water, i " '

Metol developer may be used repeatedly. An old developer
is to be recommended for overexposures. If the plate shows
a tendency to fog add from 10 to 20 drops of a 10 per cent solu-
tion of bromide of potassium to the developer.

For correct exposures the image should appear in detail within
from 4 to 10 seconds and development should be complete in
4 or 5 minutes.

As the density of the plate is somewhat reduced in the fixing-
bath development should be carried on a little further than one
would otherwise do.

For underexposed plates the normal developer should be
diluted.

4. METOL BICARBONATE DEVELOPER

is to be recommended for its excellent keeping qualities and uni-
form results. It may be used repeatedly without materially
affecting the general progress of the development. The bicar-
bonate of soda makes this developer very safe in action, prevent-
ing injury to the film and fogging of the plate.

Metric Weight. Apothecaries' Weight.

10 grammes. . . Metol i oz.

600 c.c Distilled water 60 oz.

Thoroughly dissolve the metol in the water and then add:

Metric Weight. Apothecaries' Weight.

60 grammes. . . Sulphite of soda (crystals) 6 oz.

30 grammes. . . Bicarbonate of soda 3 oz.

To prepare this developer with the hydrometer, mix:

Metric Weight.

300 c.c (30 oz.) Sulphite of soda solution testing. ... 75 deg.

300 c.c ("30 oz.) Bicarbonate of soda solution testing. . 50 deg.

10 c.c ( i oz.) Metol dissolved in 1 20 c.c. (12 oz.).. . Water



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 361

5. HYDROCHINON DEVELOPER.
A.

Metric Weight. Apothecaries' Weight.

600 c.c ........ Distilled water (hot) ...... ......... 20 oz.

120 grammes. . . Sulphite of soda (crystals) .......... 4 oz.

4 grammes. . . Sulphuric acid .................... i drachm

2 3$ grammes. . . Hydrochinon ...................... 360 grains

2 grammes. . . Bromide of potassium ............. 30 grains

Diluted with enough water to make up to

Metric Weight. Apothecaries' Weight.

960 c.c .......................................... 32 oz.

B.

60 grammes. . . Carbonate of potash ............... 20 oz.

60 grammes. . Carbonate of soda (crystals) ........ 2 oz,

With enough water to make up to

Metric Weight. Apothecaries' Weight.

960 c.c .......................................... 32 oz.

C ("ACCELERATOR").

30 grammes. . . Caustic soda ...................... i oz.

300 grammes. . . Water ............................ 10 oz.

D ("RESTRAINER").

14 grammes. . . Bromide of potassium .............. \ oz.

150 c.c ........ Water ............................. 5 oz.

For the normal developer take

Metric Weight. Apothecaries ''Weight.

30 c.c ........ Solution A ........................ i oz.

25 c.c ........ " B ........................ foz.

120 c.c ........ Water .................. . ......... 4 oz.

The working temperature of this developer should not vary
much between 65 and 75.

For underexposure add a few drops of solution C to the normal developer
" overexposure " " " " " " D



" "



362 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

More of solution A (as given for the " normal developer ")
will increase the density and more of solution B produces an
increase in detail.

Should the negative, after development with hydrochinon,
show yellow stain, it may be cleared and intensified, if need be,
by immersion in the following bath:

E.

Bichromate of potassium 10 parts

Hydrochloric acid 10 "

Water 1000 ' '

The stained negative is kept in this solution until it appears
completely bleached, when it should be well rinsed in running
water. If the bleached negative be now developed anew no
trace of fog will appear; redevelopment should be carried on
until the desired strength and density may be attained.

The following hydrochinon developer is recommended by
L. E. Jewell for photographing clouds with a ray-filter:

A.

Metric Weight. Apothecaries' Weight.

30 c.c Hydrochinon i oz.

150 c.c Sulphite of sodium (crystals) 5 oz.

750 c.c Distilled water (hot) 25 oz.

7 c.c Alcohol (95%) I oz.

After the sulphite of sodium has been dissolved in hot water
add the hydrochinon and shake well. Filter the solution, add
the alcohol, and again shake well.

B.

Metric Weight. Apothecaries' Weight.

30 c.c Carbonate of potassium i oz.

30 c.c Ferrocyanide of potassium i oz.

360 c.c Distilled water 12 oz.

The ferrocyanide of potassium acts as an accelerator for the
hydrochinon. For the normal developer take

Metric Weight. Apothecaries' Weight.

90 c.c Solution A~ 3 oz.

30 c.c ' ' B i oz.



DEVELOPMENT OF ORTHOCHROMATIC DRY- PL AXES. 363

adding from 6 to 10 drops of a 10 per cent solution of bromide
of potassium to this mixture.

Development may be begun with the " normal developer "
and if signs of over or underexposure are noted the developing-
bath should be modified to the following mixtures:

For overexposure : 3^ volumes sol. A;

i volume sol. B;

^ \ volume of a ten per cent bromide of potassium solution.

For underexposure : 3 volumes sol. A;

i volume sol. B, omitting the bromide of potassium sol.

In changing from one of these developers to the other the
plate had best be rinsed in clear water, although this would
not be necessary when changing the plate from the underexpos-
ure bath to the normal developer, nor when transferring the
plate from the normal to the overexposure bath.

6. METOL HYDROCHINON DEVELOPER.
For use in winter, dissolve in the order given:

Metric Weight. Apothecaries' Weight.

7 grms Metol \ oz.

7 grms Hydrochinon \ oz. in

2400 c.c Distilled water 80 oz., then add

120 grms Sulphite of soda (crystals) 4 oz.

75 grms Carbonate of soda (crystals) 2$ oz.

To prepare this solution with the hydrometer, mix in the
order given:

Metric Weight.

600 c.c (20 oz.) Sulphite of soda solution testing. .. .60 deg.

600 c.c (20 oz.) Carbonate of soda solution testing. .30 deg. with

7 grammes (| oz.) metol and 7 grammes ( oz). hydro-
chinon dissolved in
1200 c.c (40 oz.) Water.

For summer use this normal developer should be diluted with
an equal quantity of water to keep the development under good
control. If the negatives show too much contrast less hydro-
chinon and more metol may be taken.



364 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

7. BROMO-HYDROCHINON DEVELOPER.

Bromo-Hydrochinon Developer recommended for developing
overexposed plates and for producing density in the negative.



Metric Weight. Apothecaries' Weight.

750 c.c Distilled water (hot) 25 oz.

90 grammes. . . Sulphite of soda (crystals) 3 oz.

15 grammes. . . Hydrochinon \ oz. *

7 grammes. . . Bromide of potassium | oz.

B.

750 c.c Distilled water 25 oz.

1 80 grammes. . . Carbonate of soda (crystals) 6 oz.

For the normal developer take equal volumes of A and B.
If the plate shows signs of underexposure it should be immersed
in a freshly prepared and diluted developer, and if sufficient
detail does not appear in this bath, the plate should be removed
to another tray containing water to which a little of the alkaline
solution (solution B) has been added, leaving the plate in
this bath as long as an increase in detail may be noted. If
still weak, development may be finished in a fresh developer.



Online LibraryJohn Adolphus FlemerAn elementary treatise on phototopographic methods and instruments, including a concise review of executed phototopographic surveys and of publicatins on this subject → online text (page 28 of 33)