Part 16

When all is ready for exposure, place the printing frame upright opposite the lantern at the mark indicating eighteen inches (see fig. 2), note the time on the seconds hand of the clock and throw the lever over for white light for four seconds and then reverse it. Remove the paper and if many are likely to be required from that negative, it would be well to develop the first print in order to judge as to the accuracy of the exposure. If over or under-exposed, the time must be reduced or lengthened as required. When the best time and distance has been ascertained for a certain negative, mark it with a narrow strip of paper bearing full particulars for future guidance, such as: "4 sec., 18 in., No. 5 Bray;" in this way absolute correctness of future exposures is assured. Of course, if gas is not obtainable, magnesium ribbon may be used instead. In this case the negative would be marked "1 inch (or more) ribbon, 3 ft. distant," as the case may be.

_Using Masks and Discs._--Prints are sometimes required with an oval (or square) centre and white margins: this is effected by interposing a black mask of the desired size and shape (obtainable from all dealers) between the negative and the sensitive paper. The black paper prevents the passage of light and leaves white margins to the print. If grey margins are required, a disc (to fit the mask) is attached to a sheet of glass the same size as the negative and arranged so that registration is easily effected; the print is first made with a mask and is then placed in contact with the disc and plain glass (the negative being removed from the frame), and again exposed for a second to the light. If a black border is required the exposure of the margin must be extended three or four seconds.

_Vignetting._--To vignette bromide prints, the printing frame must be covered with a piece of cardboard in which a small hole (about 1-1/2 inches by 1 inch for a cabinet head and bust) is pierced. The hole _must_ be covered with a sheet of white tissue paper which will diffuse the light and cause it to travel without harsh lines beneath the opening, and make the print with perfectly gradated edges. It is sometimes an advantage to move the negative while printing vignettes; but it is not absolutely essential if the hole in the cardboard is not too large and if the card is removed some little distance from the negative. If the card is too close to the negative, the gradation will be abrupt and the vignette will not look well.

_Cloud Printing._--This requires some care in order to avoid harshness and sharply defined lines. If the sky of the negative prints white, the addition of clouds from another negative is not difficult; but if it is at all thin, the entire sky must be carefully painted out with a deeply opaque pigment in order to make it quite dense and unprintable.

As a bromide print cannot be examined while in progress: that is, cannot be seen at all before development, careful registration is desirable in order to prevent printing the clouds across the landscape instead of above it. To do this an opaque mask should be made thus: Make a print from the negative on P.O.P. and, without fixing or toning it, cut it carefully in two parts following the horizon line as nearly as possible, then expose to light, until quite black, that part representing the landscape. Attach this to the glass side of the cloud negative (with the paper side of the P.O.P. in contact) and see that the bottom edge and the right corner of the paper and glass (viewed from the glass side of the negative) exactly coincide. To make use of this arrangement, you first make a print from the landscape negative, making sure that the negative and paper are firmly pressed against the bottom and left-hand side of the printing frame when looking towards the film side of the negative; mark the registered corner with lead pencil thus =L= in order to prevent mistakes in the second printing.

To print the clouds, you put the negative in the frame and press it well home to the left-hand corner and the base of frame (looking at the film side, of course), and then put the print in contact with the same precaution and replace the back. Now take a piece of brown paper with one edge roughly torn in shape of the horizon line of the mask and cover the entire negative on the glass side. Hold the covered frame in your hands at a distance of (say) four feet from the gas and turn on the white light. Directly the light is up, draw the paper slowly downwards until the horizon line is just passed, and then _immediately_ begin to slowly push it upwards towards the top of the sky. Do this steadily and slowly for (say) four to six seconds, according to the density of the cloud negative. With a good thin cloud, four seconds should be quite enough, but you can easily settle this point on developing the first print.

_Printing from Dense Negatives._--Dense negatives require much longer exposures than those of "average" (or ideal) density. This may often be prolonged to twice or three times the normal exposure at the same distance. A yellow coloured negative increases the exposure greatly, as much as ten to thirty times the normal frequently being requisite to get a decent print. An over dense negative that gives very harsh prints by other printing processes can be made to yield prints of exquisite softness on bromide paper by giving a full exposure at a _short_ distance from the gas.

_Printing from Thin Negatives._--Thin negatives on the other hand, require quite different treatment. In order to get plucky prints from very thin negatives, useless in other processes, we must give a very brief exposure at some distance from the gas; and here it may be well to note that removing the negative to a greater distance from the light is equal to decreasing the actual time of exposure and has other advantages in connection with thin negatives with which theory does not seem to agree. To print from a very thin negative, then, instead of four seconds at eighteen inches, let us cover it with a sheet of tissue paper and give it four seconds at a distance of three or four feet and note the result on development. If it appears to be over-exposed, we may reduce the time of exposure to three seconds at the same distance and modify the developer, as will be explained later on.

_Development of Prints._--All my remarks in this article apply equally to most commercial brands of bromide paper; but it is only fair to state that they are particularly intended for that made by the firm of manufacturers publishing this book. Development, and so on, is very similar with all makes of paper, but most of my recent experiments have been made on the "Barnet" matt surface bromide.

I shall presently describe the use of several well-known developers, but it must be well understood that, whatever formula is adopted, a preliminary soaking of the print before development must be done.

When we are about to develop a number of prints we must first soak them in plain cold water until quite flaccid, otherwise the application of the developer would cause the dry print to cockle and curl, and the development would not be regular. This rule applies equally in the case of one print only as when a hundred are ready for development; a prolonged soaking in plain water having no ill effect.

_The Iron Developer._--This is one of the developers most frequently recommended for bromide work, but personally I never advise its use (especially by a novice) because the use of the acid clearing bath, which is an essential part of the process, is so frequent a cause of disaster and yellow prints. The Barnet formula is as follows:--

A. Potassium oxalate 1 lb. Potassium bromide 5 grains Hot water 48 ozs.

B. Iron sulphate 1 lb. Citric acid 4 drams. Hot water 32 ozs.

To six ounces of A, add one ounce of B; this order of mixing must be observed or a dense precipitate of ferrous oxalate will be formed.

Place one of the soaked prints face (which may be distinguished by its "slippery" surface) upwards in a clean porcelain dish and pour the developer over it as evenly as possible. With this developer, the image comes up very rapidly, so that it is not advisable to try and develop more than one at a time. If the first print of a batch appears to be over-exposed, that is, if it flashes out instantly and the high-lights become rapidly clouded, add to each ounce of mixed developer from 10 to 30 drops of a ten per cent. solution of potassium bromide which will act as a restrainer, retard development, and keep the high-lights clear while the shadows acquire density. Under-exposed prints can rarely be made to give passable results with ferrous oxalate. The addition of a trace of hypo to the developer has been recommended for bringing up their detail, but the result is far from good.

As soon as development is complete the prints must _not_ be put in clean water, but must be transferred direct from the developer to the following acid bath:--

Acetic acid 1 dram Water 32 ounces

After an immersion of one minute, the operation must be twice repeated in similar baths that have not been previously used; this is to remove the iron from the print. A thorough washing must next be given to remove the acid and the print may then be fixed for at least fifteen minutes in

Hypo 2 ounces Water 20 ounces

After fixing (no matter what developer has been used) the prints must be thoroughly washed in several changes of water for at least two hours.

The chief reasons against the use of ferrous oxalate are lack of control over development and the necessary use of an acid bath. Unless the acid bath is used, the prints will be yellow because of the iron in them, and if the acid is not entirely removed before fixing the prints will be yellow owing to the decomposition of the hypo by the acid in the print which causes deposition of sulphur.

_Metol Developer._--With this, and the other developers I shall mention, an acid bath is not necessary and so one cause of failure (and extra work) is obviated. I have somewhat amended the Barnet formula to meet the needs of workers on a small scale and have also arranged A and B to balance each other without disturbing the relative proportions of the ingredients.

A. Metol 120 grains Water (cold) 24 ounces

Dissolve _completely_ and then add

Sodium sulphite 2-1/2 ounces Potassium bromide 15 grains

Shake until completely dissolved but do not apply heat.

B. Potassium carbonate 350 grains Water 8 ounces

For use, mix three parts by measure of A and one part of B.

With this developer and a normal exposure, the image should appear in a few seconds and development should be complete in about two minutes. As fast as the prints are developed they should be immersed in

Salt 2 ounces Water 20 ounces

to stop development. When all are developed, they must be rinsed for a minute or two in clean water and then fixed. Over-exposure is remedied by the addition of potassium bromide solution (as in the case of ferrous oxalate); under-exposed prints should be developed in a weak solution such as

A 3 parts B 1 part Water 4 parts

Development will take longer, but the weaker solution will help to bring up the detail without the harshness of the shadows that would be the case if the normal developer was used.

_Hydroquinone and Eikonogen._--The advantage of combining eikonogen with quinol lies in the fact that one provides what the other lacks, the eikonogen tending to give detail without density and the quinol (in inexperienced hands) giving density without detail. The following formula will be found very satisfactory:--

A. Quinol 40 grains Eikonogen 120 " Sodium sulphite 480 " Citric acid 20 " Water to 20 ounces

Dissolve the sodium sulphite and citric acid in 15 ounces of water, then add the other ingredients and enough water to make a total bulk of 20 ounces.

B. Sodium carbonate 60 grains Sodium hydrate 30 " Potassium bromide 5 " Water to 20 ounces

For use, mix one part of A, one part of B and two parts of water. The same remarks as to over and under-exposure apply as in the case of metol.

_Toning Bromide Prints._--The "tone" or colour of the deposit depends largely upon the accuracy of exposure and the developer employed. Ferrous oxalate gives a rich black deposit, but to my mind metol and the combined eiko-quinol give tones at least as beautiful with pretty gray half-tones.

But some people prefer warmer colours, brown and red for instance, and some get brownish blacks (through over-exposure and the use of bromide) which they would like to change.

The colour of the deposit may be changed in various ways by treating the print in baths of different metals. I will give a brief outline of the methods employed, leaving readers to modify them to suit each particular case.

_Black and Blue-black Tone._--Brownish black prints can be much improved after fixing by immersion in a strong bath of gold chloride; the following is the strength used by me:--

A. Ammonium sulphocyanide 20 grains Water 1 ounce

B. Gold chloride 2 grains Water 1 ounce

When quite dissolved add B very gradually to A, shaking almost continuously. The fixed print should be washed for at least fifteen minutes before toning and should then be placed in a clean tray while the toning bath is poured over it. The solution must be kept moving and the print must be removed and washed directly the desired tone is reached. Prolonged immersion will cause the print to acquire a deep blue tone.

_Brown and Red Tones with Uranium._--Prints immersed in the uranium toning bath gradually become warmer in tone, changing from black to brown and brownish red until they assume a deep red nearly approaching the well-known Bartollozzi chalk.

Prints to be toned by this process must be _thoroughly_ free from hypo or stains will be the inevitable result. The toning bath should be made up as follows, and it must be used at once as it will not keep after mixing A and B:--

A. Potassium ferricyanide 20 grains Water 20 ounces Glacial acetic acid 1 ounce

When quite dissolved add

B. Uranium nitrate 20 grains Water 1 ounce

Immerse the print and keep the solution in motion until the desired colour is produced, then wash the print for half an hour in several changes of water acidulated (1 dram in 30 ounces) with acetic acid. Weak, under-developed prints are much improved by this method of toning.

At the end of half an hour, if the whites are at all yellow they may be cleared by immersing the print for a minute or two in the following bath:--

Ammonium sulphocyanide 20 grains Water 10 ounces

After immersion, rinse the print for five minutes and dry.

_Intensification._--It sometimes happens (especially when too little light has been used to properly judge development) that one acquires a collection of prints that, owing to under or over-development, are useless; let us see how they may be rendered serviceable.

An under-developed print, though weakly looking and "washed out," simply needs intensification to give it the requisite pluck. The foregoing uranium bath acts as an intensifier while conferring a ruddy tone on the deposit. A black deposit can be obtained by intensifying the well-washed print with mercury. The print must first be immersed in a saturated solution of mercuric chloride until the image disappears; it must then be again thoroughly washed to remove all traces of free mercury and may then be redeveloped by flowing over it an old ferrous-oxalate developer. If ferrous oxalate is not at hand, an old metol developer may be substituted, but the former is the more reliable.

When the image is sufficiently intense, the print must once more be thoroughly washed. All the toning and intensifying operations may be conducted by daylight.

_Reduction of Density._--Over dense prints can be made fit for many purposes by means of a "reducer" capable of dissolving part of the deposit. The best for the purpose and the one least liable to cause stains is know as the Belitzski's; it is prepared thus:--

Water 60 ounces Potassium ferric oxalate 3 " Sodium sulphite 3 "

Dissolve and add to the red solution so obtained.

Oxalic acid 1 ounce

Shake until the solution turns green and then immediately pour off the solution from any crystals remaining undissolved. To this solution add

Hyposulphite of soda 15 ounces

and shake until dissolved, when it is ready for use.

The print to be reduced need not be free from hypo, but should be rinsed for a few minutes after fixing (or soaked until limp, if previously dried) and may then be placed in a tray and flooded with the reducer. The tray must be well rocked and the print, when sufficiently reduced, must be removed without delay and rapidly washed in running water.

_Some Cheap and Useful Trays._--If large-sized prints are made, the cost of suitable trays becomes a very serious item. The expense of these may be reduced to a mere nothing, without loss of effectiveness, by the substitution of home-made ones. All that is required to make a tray of any size is a thin wooden confectionery box (or the bottom part of a larger case) lined with the shiny white marbled oilcloth known as "American moleskin." This is fitted inside the box (the corners being turned under) and secured by a row of tacks around the top edge. No further lining or preparation is required and the tray will stand all sorts of ill-treatment. As for durability: I had three such trays made out of old herring-boxes picked up at Calgary and lined with moleskin that had already seen service as cover to a wash-handstand and chest of drawers in a Canadian boardinghouse. For upwards of a year those trays were used daily and travelled many hundreds of miles by mule and dog train, and were not worn out when I returned home. My porcelain trays were smashed by a fall from a refractory mule, but the rough and ready makeshifts were a priceless boon.

It seems to me that by practising economy of this kind and in various similar ways (_i.e._, where economy is necessary as, unfortunately, it sometimes is) the cost of practising our pet recreation is very materially reduced.

_W. Ethelbert Henry, C.E._

_The Gum-Bichromate Process._

Pictorial photography is answerable for the revival of this, one of the almost forgotten methods of printing. Results unacceptable to bygone requirements have been reintroduced with advantage, where suggestive individuality and artistic effect have been desired.

The gum process has an unlimited range of possibilities, it would be impossible to describe them all. The minutest details, or the broadest diffusion together with the power of working from the highest to the lowest keys of _chiaroscuro_ are values that can only be realized when the infatuation consequent on successfully working the process is experienced.

This method of printing, as with the so-called "carbon process," is dependent upon the characteristic behaviour of the chromic salts when in combination with organic substances, such as gelatine, gums of various kinds, starch, etc.

When any of these mixtures are submitted to the action of actinic light, they become more or less insoluble.

This property was partially discovered as far back as 1798, by Vauquelin. Professor Sucrow, Mungo Ponton, Beauregard and others advanced its application to photography up to about 1840, but it was not until some ten years later that its great value as a photographic agent was definitely established.

Hunt, Fox Talbot and Poitevin, each worked indefatigably to bring the application of the chromic process to a successful issue; but to Poitevin must be accredited the honour of being the original inventor of the chromated pigment or carbon process. This brings us up to about 1855.

None of these investigators appear to have been remarkably successful, beyond having established definite, but valuable facts of the changes produced.

This want of success may possibly be accounted for by the general employment of gelatine and direct printing. It was not until Pouncey and others, about 1859, employed gum as the colloid medium, that any great advance was made.

About this time an important commission of inquiry decided that to Pouncey, Gamier and Salmon, and Beauregard the honour of producing permanent prints must be equally credited, and accordingly divided the Duc de Luyue's prize between them, giving to Poitevin the credit of the priority of invention.

Pouncey appears to have followed up the process with some considerable success, as some of his existing examples are excellent; it is much to be regretted that we have not more detailed particulars of his methods of working; but he evidently was before his time and met with but little encouragement.

To Alfred Maskell and M. Demachy must be accredited the revival of this long neglected process, and during the last three years much advancement has been made towards perfecting it.

Serious workers, both at home and abroad, are industriously exhausting the possibilities of the process, and crude as some of the earlier examples of this revival have been, improvements and simplicity of working are giving us productions of every description, of such excellent quality that it may soon be expected to satisfy even the caustic criticism that has so persistently opposed its re-introduction.

Dexterity in the various stages of practical manipulation is necessary before skilful efficiency can be secured, and in order to arrive at this, due consideration must be given to the selection of the paper the colour most suitable to the subject and the effect desired.

Almost any kind of paper will be found workable, if it be of fairly good quality. Those that are thickly coated with soluble sizing media are unsuitable, for although they may give clear whites they sometimes produce harsh prints, the half-tones are also liable to be lost in development unless very deeply printed. Several of the continental kinds are well adapted to the process and work in an excellent manner, giving soft and even results; of course, it will be understood that for definition and fine detail the finer grained descriptions are the best, but where diffusion is desired those of a coarser texture may be advantageously used, they give a granulation that tends materially to secure the peculiarities of gradation characteristic of this process.

A few of the continental papers that will be found to work with ease to the beginner, are as follows:--

Michallet paper is rather coarse, but takes the gum coating easily, it has a series of lines running in both directions, which are rather objectionable for some subjects; but it is an excellent paper for first experiments.

Ingrés, is also a paper of similar character, and can be worked with equal facility. Lallane is another paper of the same class, but much finer.

Allongé paper is entirely free from the markings peculiar to those previously mentioned. This paper is best worked on the reverse side, which can be distinguished by examining the name marked in one corner.

Among the English papers the ordinary cartridge, Whatman's drawing papers and many others are adaptable, but it must be borne in mind that those with a toothed or grained surface are preferable.