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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 29 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 29 of 33)
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8. EIKOXOGEX DEVELOPER.
A.

Metric Weight. Apothecaries' Weight.

15 grammes. Eikonogen i oz.

60 grammes . Sulphite of sodium (crystals) 4 oz.

0.3 gramme.. Bromide of potassium 10 grains

900 c.c Distilled water 60 oz.

B.

45 grammes. . . Carbonate of soda 3 oz.

300 c.c Distilled water 20 oz.

For the normal developer take 3 parts of solution A and i
part of solution B, adding i drop of a 10 per cent solution of



DEVELOPMENT OF ORTHOCHROMATIC DRY- PLATES. 365

bromide of potassium to each 30 c.c. (each oz.) of mixed
developer.*

If the " acid fixing-bath " be used after development with
eikonogen the negatives are apt to be marred by semi-transparent
streaks. |

9. "EIKO-CUM-HYDRO" DEVELOPER.
A.

Metric Weight. Apothecaries' Weight.

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

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

22 grammes. . . Eikonogen 330 grains

10.5 grammes. Hydrochinon 160 grains

adding enough water to make up to

Metric Weight. Apothecaries' Weight.
960 c.c 32 oz.

B.

600 c.c Distilled water 20 oz.

60 grammes. . . Carbonate of potash 2 oz.

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

adding enough water to make up to

Metric Weight. Apothecaries' Weight.
960 c.c 32 oz.



* For developing bromide paper prints add 2 parts distilled water to the normal
developer as given here. The developer should be renewed after each 4 to 6
prints have been developed.

t The following "fixing-solution" should be used with this developer for both
plates and bromide prints, as it prevents all possibility of the developer staining
the negative:

Metric Weight. Apothecaries' Weight.

60 grammes Hyposulphite of soda. 4 oz.

15 grammes Bisulphite of sodium i oz.

300 c.c Distilled water 20 oz.

This fixing-solniion remains colorless after repeated use.



366 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

For the normal developer take

Metric Weight. Apothecaries' Weight.

30 c.c Solution A i oz.

15 c.c Solution B 4 drachms

90 c.c Distilled water 3 oz.

More of solution A would increase the density of the nega-
tive and more of solution B would tend toward an increase in
detail.

10. AMIDOL DEVELOPER.

Metric Weight. Apothecaries' Weight.

600 c.c Distilled water 20 oz.

4 c.c Sulphurous acid. . i drachm

15 grammes.. . Sulphite of soda, granular, dry 4 drachms '

3 grammes. . . Amidol 46 grains

Dissolve the chemicals in the water in the order given. With
this developer the image should appear rather quickly with full
intensity and a wide gradation of tones.



C. Fixing the Negative.

After removal from the " clearing-bath," the negative is
placed in the " fixing-bath " to preserve the developed image,
to render the negative light-proof.

After the proper stage in the development of the plate has
been reached, by immersion in one of the preceding developers,
in the dark-room, the negative should be well rinsed in clear
running water to remove all traces of the developing and clearing
solutions. It may next be placed in the " clearing-bath " given
under "iron developer" (ferrous oxalate), solution D. This
bath should not be omitted after development with ferrous
oxalate, but it may be omitted when using most of the other
developers. After removal from the clearing-bath the negative
should again be rinsed in clear water before it is subjected to the
" fixing-bath."



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 367

Metric Weight. Apothecaries' Weight.

4 c.c Sulphuric acid i drachm

480 grammes. . . Hyposulphite of soda 16 oz.

60 grammes . . . Sulphite of sodium (crystals) 2 oz.

30 grammes . . . Chrome alum * i oz.

1920 c.c Distilled water (warm) 64 oz.

This acid fixing-bath should be mixed in the following order:
Dissolve the hyposulphite of soda (16 oz.) in 1440 c.c. (48 oz.)
of warm distilled water, the sulphite of sodium crystals (2 oz.)
in 1 80 c.c. (6 oz.) water. Next dilute the sulphuric acid
(i drachm) with 60 c.c. (2 oz.) water and pour this slowly
into the sulphite of sodium solution and add this to the hypo-
sulphite of soda solution. Now dissolve the chrome alum (i oz.
in summer and \ oz. in winter) in 240 c.c. (8 oz.) of warm
distilled water and add this solution to the bulk of the mixture,
when the fixing-bath (after cooling) will be ready for use.

This fixing-solution is a good keeper and will not discolor
until after repeated use. It clears the shadows of the negative
and hardens the film, thus materially preventing " frilling "
(separation of film edge from glass surface) in the final washing.

The negative should be kept in this bath until the last trace
of the milky- white appearance of silver bromide, when examined
from the back of the negative, has entirely disappeared and the
shadows have become perfectly transparent. This should require
an immersion of about 5 minutes. The negative has now become
light-proof and it should be thoroughly rinsed in clear running
water for at least one half hour, or when the water is cold, for
fully one hour, to free the film from any trace of the hyposul-
phite. Before removal from the water the film surface should
be swabbed with a wad of cotton, again rinsed, and finally be
placed in rack to dry spontaneously. If no running water is
available the washing may be done in ten to fifteen changes



* The given amount is for use in summer. In winter only 15 grammes
(4 drachms) chrome alum should be taken. An excess of alum may cause a
precipitate to form on the negative, imparting a mottled appearance to the latter.



368 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

of water, transferring the negative from one tray to the other
and refilling each tray with fresh water after passing the nega-
tive from tray to tray at intervals of five to ten minutes.

It is most important that every trace of hyposulphite of soda
be eliminated in the final washing to impart keeping qualities
to the negative. Any subsequent formation of a crystallized
coating of the film, followed by a gradual fading of the image,
may generally be regarded as the direct result of an imperfect
removal of the hyposulphite of soda in the final washing.

i. TESTS FOR PRESENCE OF HYPOSULPHITE OF SODA.

To ascertain whether the hyposulphite of soda may nave been
thoroughly removed from the film of the negative the following
tests may be applied.

The simplest test for presence of " hypo " in the last washing
is made by adding a few drops of the following solution (Prof.
Boettcher's test) to a little of the water drained from the negative:

Metric Weight. Apothecaries' Weight.

0.2 gramme .... Permanganate of potash 3 grains

i gramme Caustic soda 15 grains

460 c.c Water 16 oz.

If " hypo " be still present the red color of the mixture will
be changed to green.

This solution should be kept in a well-stoppered bottle incased
in a light-proof wrapper or box. This test is generally con-
sidered very satisfactory, as the quantity of " hypo " left in the
pores of the film must be very small indeed if the pink or red
colored solution does not change color within a few minutes after
mixing the drainings from the plate with the permanganate solu-
tion.

Another test is as follows:

Beat up a piece of starch, about the size of a pea, with j- oz.
of water and boil in a test-tube to a clear jelly. To this add



DEVELOPMENT OF ORTHOCHROMATIC DRY- PLATES. 369

one drop of tincture of iodine, which will produce a dark- blue
color. Now fill another test-tube with the drainings from the
negative and add one drop of this blue solution, stirring the
mixture well. If " hypo " be present the blue color will be dis-
charged.

Should the final washing of the negative have to be cut short,
on account of " frilling of the film," during warm weather and
in the absence of ice, or should it have to be interrupted for any
other reason, it is recommended to place the negative in a freshly
prepared " clearing- bath " (solution D, given under ferrous oxa-
late developer), or in a i : 30 solution of bromine in water, to
neutralize and destroy any " hypo " that may still be retained
in the surface layer of the film.

2. DRYING THE FINISHED NEGATIVE.

Negatives are best dried in a cool, dry atmosphere, prefer-
ably under a mild draft. In a warm, damp, or wet climate the
drying of the finished negative would proceed too slowly, greatly
increasing the density of the film, particularly toward the center
of the plate, which generally dries last. Under such adverse
conditions the drying of the films may be accelerated by flowing
proof alcohol over the film a few times before placing the nega-
tive in the rack to dry. Heat, however, should never be applied
to the negatives for purposes of drying, as it liquidizes the soft
gelatine coating. Great care should be exercised not to inter-
change the trays and vessels used for the various photochemical
solutions.

3. INTENSIFICATION OF A NEGATIVE WITH THE AID OF METALLIC SALTS.

With correct exposure and development intensification need
not be resorted to. Light somewhat retards the process of inten-
sifying, and it is advisable to conduct the operation in the dark-
room, or at least in subdued light. A negative that had been



370 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

dried after fixing is more readily acted upon by the intensifier
than one that has just been removed from the washing-tank.

Should the final negative be too thin for good printing it
may be intensified, after thoroughly washing to eliminate all
traces of " hypo," as previously noted, by subjecting it to the
following treatment :

Pour a sufficient quantity of a saturated solution of bichloride
of mercury in water into a solution of 37 grammes (ij oz.) iodide
of potassium in 180 c.c. (6 oz.) water until the point be reached
when the forming red precipitate can no longer be dissolved by
shaking. No more bichloride of mercury solution should be
added than just enough to make the solution a slight shade turbid.

Now add 28 c.c. (i oz.) hyposulphite of soda, dissolve, and
add enough water to make up 600 c.c. (20 oz.) of this inten-
sifier. Just before use dilute one part of this intensifier with
three parts of water. The weak negative is submerged in this
diluted solution, exercising care not to carry the intensification
too far, although the negative may be reduced in a measure
by again placing it in the fixing-bath for a short while. If the
negative was not perfectly " fixed " before subjecting it to the
action of the intensifier it w r ill be marred by a yellow stain.

4. INTENSIFICATION WITH SILVER CYANIDE.

After having washed the w r eak negative thoroughly for half
an hour in clear running water it should be immersed for ten
minutes in a five per cent solution of alum and again thoroughly
washed before applying this intensifier.

A.

Metric Weight. Apothecaries' Weight.

16 grammes. . . . Bichloride of mercury 240 grains

16 grammes. . . . Chloride of ammonia 240 grains

600 c.c Distilled water 20 oz.

B.

16 grammes. . . . Chloride of ammonia 240 grains

600 c.c Distilled water 20 oz.



DEVELOPMENT OF ORTHOCHROMATIC DRY- PLATES. 371

C.

Metric Weight. Apothecaries' Weight.

4 grammes Nitrate of silver 60 grains

60 c.c Distilled water 2 oz.

This nitrate of silver solution is poured, while stirring, into
the following solution:

Metric Weight. Apothecaries' Weight.

4 grammes .... Cyanide of potassium, C.P 60 grains

180 c.c. . . Distilled water. . 6 oz.



The cyanide of potassium serves as a fixing-agent; it is a
very strong poison and the solution C should be labelled " poison "
and carefully stored.

To intensify the negative enough of solution A is flowed
over it to completely submerge the film. It is subjected to this
bath sufficiently long to either partially or completely whiten
the film, according to the degree of density desired. After
removal from this bath the plate should be carefully rinsed and
immersed in solution B for one minute, again be rinsed and
then be placed in the cyanide solution (C), where it is kept until
the color of the film is changed to a dark brown or black, when
it should be removed, thoroughly washed in running water, and
placed in rack to dry. The solutions A and B should be thrown
away when once used, while the cyanide solution (C) may be
returned to its bottle to be used again.

5. PROF. R. E. LIESEGANG'S INTENSIFER.

Prof. Liesegang recommends the following solution for the
intensification of underdeveloped negatives:

Apothecaries' Weight.

r Sulphate of copper 75 grains

Sol. I -I Bromide of potassium 75 "

I Water 6^ oz.

SI II ^ Nitrate * silver 9 1 grains

\ Water 4 oz.



372 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

After the negative, which may be found .too thin to print
well, has been washed from three to five minutes in running
water to remove every trace of hyposulphite of soda (see Prof.
Boettcher's " hypo " test) it is placed for ten minutes in solution
I until thoroughly bleached. The longer the negative remains in
this bath the greater the final density will be; therefore this part
of the process should be carefully watched. Still, should the
intensification be too marked, the density may again be reduced
with the usual fixing-bath of " hypo."

After removal from solution I the negative is again rinsed in
running water, or washed in five changes of water for ten minutes,
and it is then placed in the nitrate of silver solution until it becomes
thoroughly blackened (no white spots should be apparent when
viewed from the back). The intensified negative is now washed
for at least one hour in frequent changes of water; in running
water half an hour will probably suffice.

A negative that had already been dried after fixing is more
readily acted upon than one that has just left the washing-tank.
Light retards the process materially and intensification is best
conducted in the dark-room, or at least in subdued light.

6. INTENSIFYING NEGATIVES WITHOUT THE USE OF METALLIC SALTS.

After a thorough washing in running water the negative is
immersed in the following solution:

Metric Weight. Apothecaries' Weight.

0.3 gramme Potassium bichromate ... 5 grains

0.6 gramme Potassium chloride 10 grains

0.25 c.c Hydrochloric acid 4 minims

30 c.c Distilled water i oz.

Under the action of this solution the silver deposit on the
negative is converted into chloride of silver. The plate is retained
in this bath until the image appears well bleached, when it is
removed and thoroughly washed in clear running water to elimi-
nate the chromium salts from the film. The negative may



DEVELOPMENT OF ORTHOCHROMATIC DRY- PL AXES. 373

now be redeveloped in any developer. Some operators recom-
mend soaking the plate in a dilute solution of sulphurous acid
or acid metobisulphite to facilitate the elimination of the chro-
mium salts in the washing between the bleaching and redeveloping.
Pyro-soda, pyro- ammonia, metol, and pyro-metol developers
give a considerable increase in density when used for redevelop-
ment with this method of bleaching the image of a weak negative

7. REDUCING THE DENSITY OF A NEGATIVE.

Brown and yellowish stains and also a certain iridescence
of the film surface may all be caused by having the developing,
bath too warm, too strong in alkali for the plate, or by having
used the plain " hypo " solution in fixing the negative. The
same defects may also be caused by using too old a solution in
the fixing-bath, or when the latter has been used too often, and
sometimes, too, by an insufficient fixing of the negative. A weak
solution of perchloride of iron will remove the yellow stains
when this bath is followed by an immersion in the acid fixing-
bath.

Density in a negative, brown stains, and the metallic irides-
cence may* all be removed by applying the following " reducing
solution." Dissolve

i part of red prussiate of potash in
15 parts of water.

Wrap the bottle containing this solution in yellow paper, to
delay decomposition of the solution by the effects of the light,
then dissolve

i oz. hyposulphite of soda in
15 oz. water.

Add from one half to one ounce of the red prussiate solution
to the above hyposulphite of soda solution immediately before
use and place the negative in this bath directly after fixing.



374 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

A dry negative should first be soaked in water for a few minutes.
Watch the negative carefully while it is in this reducing solution,
rocking the tray and avoiding strong light during the immersion,
and remove it to running water at once when it has been suffi-
ciently reduced or cleared.

Great care should be exercised to keep the trays and the
vessels as clean as possible and never to interchange them when
developing and fixing plates. All vessels used for developing
should never be used for any other purpose and the fixing-tray
should never be used for developing.

8. COOLING-SOLUTIONS.

To accelerate the drying of the films in a damp or wet
climate the plates may be immersed, just after the final wash-
ing, in a bath composed of equal parts of water and alcohol
before they are placed in the rack to dry. All negatives, when
dried slowly in a damp and warm atmosphere, will become more
intense than when dried spontaneously in a draught or in a cool
current of air.

Should the conditions be unfavorable enough to require
artificial heat for drying the films, it is recommended to immerse
the negatives from six to ten minutes in a solution of one part
of Woodbury Antipyr in ten parts of water, after which they
are rinsed and placed in the rack to dry. This solution may
be used repeatedly.

When the development of plates has to be carried on, during
very warm weather in localities where neither ice nor cold water
is obtainable, the several baths may be kept cooled by setting
their trays in shallow vessels that are filled with some cooling-
solution, of which we may enumerate the following:

1. One part of nitrate of sodium and four parts of water.

2. One part nitrate of ammonia and one part water.

3. One part sulphocyanate of potassium and one part water.

4. Three parts nitrate of sodium and four parts water.



DEVELOPMENT OF ORTHOCHROMATIC DRY-PLATES. 375

5. One part chloride of potassium and four parts water.

6. Three parts sulphate of sodium and two parts diluted

nitric acid.

7. Nine parts phosphate of sodium and four parts dilute

nitric acid.

8. One part sal ammoniac, one part saltpeter, and one part

water.

9. Five parts sal ammoniac, five parts saltpeter, and sixteen

parts water.

10. Eight parts sulphate of sodium and five parts concen-

trated sulphuric acid.

D. Negative Varnish.

For a better preservation of the negative, its film may be pro-
tected by a thin and uniform coating of varnish, to be applied
after the film has become thoroughly dried and hardened. The
dry negative should be carefully dusted and held near a fire until
it is uniformly warm. It is now balanced on the finger-tips of
the left hand, film side up, and a small portion of the varnish
is poured on the film surface, gradually turning and tipping the
plate to cause the varnish to flow to each corner, covering the
entire plate but not going over the same place twice. The
plate is now kept warm, still holding it in a horizontal position,
under a gently rocking motion, until the varnish has dried with-
out leaving lines or ridges.

A colorless and transparent varnish may be made by dis-
solving one ounce soft copal in ten ounces benzine.

A good negative varnish that will permit of retouching the
negative may be prepared after the following formula;

Metric Weight. Apothecaries' Weight.

10 grammes Amber powder (melted).' 150 grains

6 grammes Un vulcanized' rubber 90 grains

1750 c.c Chloroform 50 drachms

1750 c.c Benzole 50 drachms



376 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

The proportion of benzol added determines the degree of
' mat " that may be imparted to the dry coating of this varnish.



V. Photographic Printing.

Photographic printing is the process of obtaining positive
copies from a negative, on specially prepared paper (or other
sensitized material), by means of light transmitted through the
negative.

The printing process is as follows:

Place the printing-frame, face downward, on a table and
remove the backboard. Lay the negative, which should be
perfectly dry, film side up, in the frame and on this place a
sheet of sensitized paper, face down, in contact with the film.
This paper may be covered with a blotting-paper or piece of
thin felt, after which the back of the frame is replaced and clamped
in position. The frame should now be carefully turned over,
and any spots that may be on the glass surface should be removed
before exposing the negative to the light. These operations may
be conducted in the subdued light of a room when using so-
called " printing-out " papers, but even this paper should not
be exposed too long to such light and not at all to the direct rays
of any light.

The progress of the printing should be examined occasion-
ally, in subdued light, by opening one side of the backboard
of the frame and raising one end of the paper. The printing
should be a trifle darker than is desired for the final picture,
and darker when toning for blue-black tones than when toning
for warm-brown tones. If not sufficiently printed the back-
board is again closed and carefully latched. Only one side of
the back of the frame should be loosened for examination of
the print to maintain perfect registry between the paper and
the negative.

Weak negatives should be printed in diffused light by covering
the printing-frame with a sheet of tissue-paper (or with several



PHOTOGRAPHIC PRINTING. 377

thicknesses if required). Strong and dense negatives are best
exposed to direct sunlight. It is important to print a shade
deeper than required for the finished picture, as the print will
always bleach somewhat in the toning and fixing process.

Should the whites darken before the shadows become bronzed,
when printing in direct sunlight, it may be taken as an indication
that the negative is too weak for printing in intense light and its
prints should be made in the shade or in diffused light.

Should the shadows be fully bronzed before details in the
high lights appear, when printing in diffused light, it is a sign
that the negative is sufficiently dense to require printing in sun-
light.

To reduce overprinted pictures an old fixing-solution to
which a few drops of a saturated solution of ferrocyanide and
ammonia have been added may be recommended.

Prints sufficiently exposed may be collected in a light-proof
drawer or in a dark receptacle until a number are ready for toning.
There is a large variety of printing-papers in the market for
obtaining positive copies from negatives, and special directions
for their use and manipulation accompany each brand. They
may be divided into two groups. The first, comprising all papers
requiring special developing to bring out, the latent image, are
known as develo ping-out papers. These undergo the same
process as a photographic plate after exposure to bring out and
fix the image.

The second group comprises all so-called printing-out
papers (mostly gelatine or collodion papers), the image becoming
visible during the printing.

The papers of the first group (" developing-out " papers)
are mostly very sensitive and the actinic action of the light on
their sensitive silver salt is so rapid that these papers should
be manipulated in the dark-room only. The printing, too, is
best done in the dark-room with artificial light. These papers
have the advantage that they give ready means for obtaining
prints at any time irrespective of the weather, and most of them



378 PHOTOTOPOGRAPHIC METHODS AND INSTRUMENTS.

are invaluable for enlarging purposes, enabling the operator to
make prints of almost any size from relatively small negatives.
The so-called bromide, platinum, and platino-bromide papers
are well suited for making direct enlargements from photo-
topographic negatives. Such enlargements are preferably
used in iconometric plotting in place of the small contact
prints.

The papers of the second group are of special value for mak-
ing contact prints in the field; they are less sensitive to the light
than the " developing-out " papers and only require toning
and fixing after removal from the printing-frame. We find a
large variety of these papers in the market, with special direc-
tions for their manipulation and use.

The older and still popular " printing-out " paper known
as " silver-printing," " albumenized " or " sensitized albumen "



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 29 of 33)