B.donath Practical Colour Photography Chapter 14 Lippmann

8/3/2019 B.donath Practical Colour Photography Chapter 14 Lippmann

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CHAPTER XIV of Practical colour Photography B.Donath

Figures are ABSENT! Sorry this is all I have. Can anyone help with sourcing the diagrams? Still

interesting though! The text has been reconstructed with character recognition software and may contain

errors such as i instead of 1.

THE LIPPMANN PROCESS OR INTERFERENCE HELIOCHROMY

THIS is probably the most beautiful of all color processes from a theoretical standpoint and yet is also that

which has been the least practised, mainly because one has to prepare the plates, exposures are very long,

and there is no known means of reproducing the results. It has remained, therefore, purely a laboratory

process.

The first suggestion as to the possibility of this process was made by W. Zenker in 1868; it was later

suggested by Lord Rayleigh in 1887, and O. Wiener in 1890, but it was not until 1891 that G. Lippmann, of

Paris, actually succeeded in obtaining a color photograph in this way.

In order that the subject may be fully grasped we must enter, even though but superficially, into an

explanation of the rudimentary principles of light. A brief explanation has already been given of the

dispersion of light and the occurrence of the Fraunhofer lines, and the following table gives the principal of

these in the visible spectrum with their wave-lengths and the number of vibrations per second:

Fraunhofer Line Wave-length Vibrations per Second in Billions

A 7593-97 395

B" 6867.38 437 185

p186 COLOR PHOTOGRAPHY B.Donath: Chapter XIV THE LIPPMANN PROCESS

Fraunhofer Line Wave-length Vibrations per Second in Billions

C 6562.96 457

Di 5896.08 509

D 2 5 8 9- I 3 59

E 5 2 7o-43 569

bi 5183.73 579

F 4861.43 617

G 43

OI -43 696

h 4101.84 731

H 3968.61 760

K 3933-86 763

The wave-lengths are given in Angstrom units (10millionths of a millimeter.)

Beyond A lies the infra red, the invisible region of which we are sensible in the form of heat; while beyond

K is the ultra-violet, by which the chief chemical actions are caused.


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gelatine emulsion method. This latter is faster but a little more trouble to make.

For the albumen take:

Albumen 1000 ccm

Potassium bromide, 10 % solution 43 ccm

Ammonia 43 ccm

Beat to a froth and allow to stand for twenty-four hours to liquefy, and then filter through glass wool or

decant from the flocculent sediment. Glass plates should be thoroughly scoured with hot soda and water,

well washed and dried, and polished with alcohol until they show a perfectly even film when breathed on.

Ordinary glass is not as a rule thick enough, and it is more satisfactory to use white plate glass, about onesixteenth inch thick. As the film is extremely transparent and it is not easy to tell which side has been

coated, it is as well to mark the wrong side with a diamond or the edge of a threecornered file. It will also

be found that as a rule one side of the glass is smoother than the other, and this smooth side should be

coated; it is easy to detect the smoother side by holding the glass level with the eyes and glancing along it.

The albumen is the white of eggs, and if the operator is not accustomed to separating the whites from the

yolks, it is as well to break each egg separately into a cup and then strain off the white into the bulk. The

whipped and filtered albumen will keep for two or three months in a well-corked bottle.

The glass should be flowed over with this solution, drained for about thirty seconds and then placed on a

leveled slab to dry in a place free from dust. The plates should then be heated for two minutes to 60 C. (140

F.) and allowed to cool. This heating may be effected by

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COLOR PHOTOGRAPHY B.Donath: Chapter XIV THE LIPPMANN PROCESS

placing the plates on two or three thicknesses of blotting paper on top of an iron plate, or what is more

convenient, an empty cracker tin of fair size. The plates may be placed in a rack and with an ordinarySunsen burner the temperature will soon be raised inside the tin, if the lid be put on. A thermometer can be

inserted through a hole close to the plates. About four minutes of this treatment will suffice. This is lesslikely to crack the glass. A stock of plates can be prepared and packed face to face, wrapped in pairs in

tissue paper, and will keep indefinitely in a dry place. To sensitize them, the plates should be immersed in:

Silver nitrate 100 g

Glacial acetic acid 100 ccm

Distilled water to 1000 ccm

This may be used in a dish, preferably of glass. If porcelain be used, a new tray should be taken into service

to avoid any possible contamination from previously absorbed solutions. About three minutes immersion is

sufficient. They should then be drained for about one minute and immersed in distilled water for fiveminutes, the water poured off and fresh applied, and this repeated six times. They may then be color-

sensitized, and although their sensitiveness is very low only a green light should be used. The sensitizermay be:

Glycin red, i : 500 alcoholic solution 8 ccm

Cyanin, i : 500 alcoholic solution 2 ccm

Ammonia, 2 % solution 15 ccm

Distilled water to 1000 ccm


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level slab to set. Practically, the thinner the coat the faster the plate, and if the above method gives too slow

a plate, then the glass may be warmed, which will cause more emulsion to drain off.

All the original formulas for color-sensitizing called for the old cyanin, but much better results can be

obtained with the newer isocyanins, and pinachrom is very satisfactory. For the bath method use:

Pinachrom, i : 1000 alcoholic solution

5 ccm Distilled water to 1000 ccm

Borax, saturated solution 10 ccm

Bathe four minutes, rinse, and dry rapidly. As full details have already been given as to bathing and drying

plates there is no need to add more. Green light must be used as soon as the dye is added, but before that abright orange light may be used. If it is thought that sufficient red sensitiveness is not obtained with the

above dye, though this will only be noticed in spectrophotography, then a mixture of sensitol green and

sensitol violet may be used, in the ratio of two parts of the former to one of the latter; and not more than 6

ccm should be added to the bath. If the dye is to be added to the emulsion, then 3 ccm of the dye solutions

should be added to looo ccm of emulsion.

Before leaving the emulsion making it may be useful to point out that H. E. Ives has stated that the best

results are obtained in spectrum work, for which the process is eminently suited, by using the following

solutions:

A. Gelatine 20 g

Distilled water 500 ccm


B. Gelatine 40 g

Potassium bromide 5 g


C. Silver nitrate 6 g


Dissolve the gelatine, cool, add the salts, then add A to C and pour into B. Working temperature 35 C. (95

F.). Coat the plates by flowing the emulsion on to cold glass, drain off and set, and wash the plates forfifteen minutes. The emulsion should be color-sensitized by adding i ccm of the dye solution to 100 ccm, or

for bathing the strength should be i : 100,000.

As previously stated, the film is exposed in contact with mercury, and obviously the glass must face toward

the lens. The chief difficulty here is the plate-holder; it must be capable of holding the mercury withoutleakage, and the mercury must be run in and out when the plate is in position. Specially constructed holders

are obtainable commercially and it will be better to purchase one; but the following brief description maybe useful. The front of the holder carries a strip of rubber about 4 mm wide and 2 mm thick, against which

the glass is pressed. The back is a solid piece of wood, metal lined, with a rubber strip all round, and this is

a firm but resilient red rubber. The back fits tightly in place and is held by two steel cross bars that fit on

pins with fly nuts which screw it firmly into place. In one corner of the back is screwed a small steel pipe to

which is fastened a rubber tube, connected with the mercury reservoir; at the diagonally opposite top corner

is a screw, with a hole driven right through its length and a small cap fitted; the purpose of this is to allowegress



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of the air as the mercury flows in. The lower pipe is fitted with a tap; to fill the slide with mercury, the tap

is opened, the screw cap unloosened and the container slowly and gradually raised until it is higher than the

top of the holder; the tap is then turned off and the container can be laid on the back of the camera. After

exposure, the tap is opened, the container slowly lowered, and the mercury runs back. This holder and the

mercury make the whole very heavy and allowance must be made for this.

It is very important that the mercury be kept clean, and if pure in the first place it can be used repeatedly

without trouble. The best way to clean it is to procure a large chamois leather; well wash this in warm waterand soap, and dry; then soak in gasoline for an hour or two, kneading it occasionally with the hands, and

dry. This may make the leather harsh and stiff, but it can be easily suppled by pulling and working between

the hands. It should be placed in a clean dish and the mercury poured into the middle and run backwards

and forwards for a short time, and then the ends of the leather gathered together and twisted round so as to

force the mercury through.

One caution is necessary; immediately after exposure the mercury must be run out; if left in contact with

the film, the latent image on this is completely destroyed.

It is impossible to give a very definite idea of exposure, but the plates are from 1000 to 2000 times slower

than a fast plate. For a landscape in bright sunlight, with a lens working at / : 4.5, the exposure will be from

one to two minutes. It will be seen that portraiture by this process is almost impossible, though Professor

Lippmann did succeed in taking some very good portraits. For


still life the plates are excellent. For spectrographic work, with a slit width of 0.3 mm, a condenser and

sunlight, the exposure will be about one minute.

For development pyro-ammonia has been the favorite, and the following is a typical formula:

A. Pyrogallol 1 g Distilled water 100 ccm

B. Potassium bromide 20 g

Ammonia, sp. gr. 0.96 67 ccm


For use, mix 10 parts A, 20 parts B, and 140 parts water. Duration of action about three minutes, and the

plate should be at once well washed.

There has been considerable discussion as to whether these pictures should be fixed or not; for the mostcorrect rendering of color they should not be, and this is particularly applicable to spectrum work. If they

are fixed the distance of separation of the silver laminae is slightly reduced and consequently there is a

slight change of color. For ordinary work, the best fixer is a five per cent solution of potassium cyanide,

which should not be allowed to act longer than ten to fifteen seconds; then the plates should be rapidly

washed under a tap for about ten minutes and dried.

An alternative process and one which has much to recommend it, is development with the following

hydrochinon developer:

Hydrochinon 3 g

Sodium sulphite, dry 7.5 g

Potassium carbonate 2 g

Potassium bromide i g


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Water to 100 ccm


After washing for ten minutes, the plate should be immersed in a one per cent solution of mercuric chloride

and dried. This gives the most brilliant colors.

The colors are only seen when the pictures are examined at a certain angle, and then are very pale, due tothe reflection of white light from the surface of the film. To destroy this a glass prism of low angle, 10 to

12 degrees, is cemented to the surface with Canada balsam. These prisms can be obtained from any opti

C FIG. 22 D

cal house at a reasonable price, as accuracy of surface and angle are not important. The Canada balsam

used must be diluted with benzol or xylol, not chloroform, as the latter in time bleaches the image. Beforesealing with the prism, a very pretty experiment can be performed. Examine the picture at the best angle,

and it is better to support it in one position and shift your position until this is attained. Then, with a glasstube, blow on the film and the colors will be seen to change as the gelatine between the laminae swells. All

colors become more red, while as the moisture dries out they


change back to blue. It is thus possible to slightly alter the colors of a heliochrome, either by warming ordamping, and as soon as the correct colors are seen it should be cemented up. The prism should be clipped

on to the picture and then it should be placed in a warm place to dry. When dry, the excess balsam should

be scraped off, the edges bound up with black paper, and the back of the glass bearing the picture painted

with black varnish. These pictures are best seen when side light is pre

FIG. 23

vented from reaching their surfaces, and a viewing box can easily be made as shown in Fig. 22. In thisABCD is the box, in one end of which is supported the heliochrome, while at the other end is a peep hole Ethrough which the picture can be seen. M is a small piece of mirror, adjustable on a hinge, which throws the

light through the aperture KL cut in the top of the box. For exhibition on a screen with a lantern, the

principle of the aphengescope or opaque object lantern projector must be used,


as shown in Fig. 23, in which A represents the arc, C the condensers, and A' the image of the arc. The

heliochrome is placed in the plane HE', so that the beam of light just covers the picture, and L is theprojection lens, which should be placed as far from HE' as this is from the point A', so that the image of the

arc falls in the objective; the picture will then be shown on the screen SS'.

End of Lippmann chapter

CHAPTER XV THE SEEBECK PROCESS OR PHOTOGRAPHY WITH SILVER SUBCHLORIDE

THIS is another interesting laboratory process of no practical value as, so far, no means of fixing the

images has been discovered. It is named after J. T. Seebeck, who, prior to 1810, sent to the poet Goethe atreatise on the action of light on silver chloride, in which he disclosed the fact that under the influence of

the spectral rays it assumed the colors incident upon it.


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B.donath Practical Colour Photography Chapter 14 Lippmann