PhotoHistory

Complete Self-Instructing Library of Practical Photography
Volume I - Elementary Photography 1909

The Kallitype Process.

Introduction.

Of the various simpler processes which admit of practically any kind of paper being prepared and sensitized by the individual worker, the process known as kallitype embodies a method of printing which, although known and used for many years, deserves a much greater list of users. The three strongest points in its favor are: First, the extremely small expense connected with the process; second, the close imitation which the final print bears to the more expensive platinum process; and third, the simplicity of sensitizing, printing, developing and fixing.

The rapidly increasing scarcity of metallic platinum makes it necessary for the amateur worker to obtain something “to take the place” of platinum paper. It is not necessary to look further than the kallitype for results quite as good as will be found in platinum. The permanency of the kallitype is just as good as any other silver process. The richness of deposit in the metallic particles usually associated with the platinum image can equally be claimed for the silver image of the kallitype, the basis of both being ferro-oxalate. In fact, kallitype at its best cannot be distinguished from platinum.

In the first experimental stages of this process it was customary to coat the paper with a solution of ferric-oxalate (an iron salt) and develop the image which was secured by printing through a negative in strong daylight, in a bath of silver nitrate. This method was soon discarded for another, in which the iron and silver were combined in the sensitizer and the faint image which was secured in printing brought to full strength in a solution of rochelle salts, borax, or a combination of the two. In fact, this is one of the simplest methods of procedure, and we give here the process in its simplest form.

Theory of Process.

Upon exposure to light the ferric-oxalate is reduced to a ferrous salt, which when dissolved by a suitable solution has the power of reducing silver nitrate to a metallic silver, and this reduction takes place in that degree in which the light has altered the ferric salt.

A Satisfactory Formula.

Ferric-oxalate 75 grains
Silver Nitrate 30 grains
Distilled Water 1 ounce

This bath may be prepared in any quantity, but in the same proportions.

The ferric-oxalate should be dissolved in the water first and care must be exercised at this stage. It requires warm water to dissolve it, but this must not be too hot, or it may spoil the oxalate. After it is dissolved, the liquid should be cooled and filtered and the silver nitrate added. The solution should then be quite clear.

The Paper.

A fairly good quality of paper should be used for the process — good writing or drawing paper will generally be found suitable, although most any paper may be used. Some papers require to be sized first, for which purpose arrowroot should be used. A peculiar feature about the process is that the paper employed has a considerable influence upon the color of the final print, some papers giving a much warmer color than others with the same developer. The nearer chemically pure, however, the paper, the greater will be the success in securing rich black images. Where the cheaper qualities of paper are used it will be difficult to secure excellent blacks; therefore, it is advisable when using cheaper grades of paper to develop for the warmer colors.

Sizing the Paper.

As previously stated, it is not necessary to size the paper; but if the best of results are to be secured it will be found advisable to coat the paper with a solution prepared by grinding in a mortar 10 grains of arrowroot in about 1/2 ounce of cold water, and then adding 5 ounces of hot water and bringing to a boil, when the milkiness will disappear.

In sizing the paper you can either float it upon the solution, being sure that all air-bells are expelled, or, the sizing may be brushed into the surface of the paper with a camel-hair brush.

Sensitizing the Paper.

Pin the paper to be sensitized on a table or board and apply the solution with a camel-hair brush or a tuft of cotton (the brush is to be preferred). It is impossible to state the exact quantity of solution to use, as the rough or porous papers require more liquid than those which are well sized or of a smooth surface. The paper may be coated by gaslight, or lamp-light, without fear of fogging it. It is about as sensitive to light as platinum paper and, therefore, should not be unduly exposed to daylight.

It should be dried thoroughly in the dark-room, and unless it is to be used at once, stored in a tin tube containing calcium after drying. As the coating is very simple it is not necessary to sensitize large quantities of paper at once; furthermore for black tones the use of freshly-coated paper is essential. Sepia tones are best secured on old paper.

Printing.

The greatest amount of skill required in this process comes in the printing, much depending upon its being done correctly. The image is only partly printed out, resembling platinum paper in this respect, in that the image is a grayish blue upon a lemon-colored ground. No great difficulty will be experienced, however, if you bear in mind that those portions of the iron salts which are affected by the light are the parts that will come out strong when the developer is applied. Wherever it is desired to have the picture tinted there must, in that same degree, be darkening of the iron salts. Damp paper will not give good black tones and, therefore, one should use the same precautions exercised when using platinum paper. After a few experiments the required depth of printing will be easily ascertained.

Development.

It is necessary that the print be developed soon after printing, as there seems to be a continuous printing action. If the paper were kept for a number of hours before being developed it would flash up in the developer and show all the appearances of over-printing.

Developing Solutions.

I. For Cold Tones.

Hot Water 20 ounces
Borax 7 drams
Rochelle Salts 1 ounce

Hot water must be used to dissolve the borax. After the borax is thoroughly dissolved, the solution should be cooled and the rochelle salts added.

II. For Warm Tones.

Water 20 ounces
Rochelle Salts 1 ounce

III. Restrainer.
Water 5 ounces
Potassium Bichromate 25 grains

The restrainer plays an important part in the process — the more used the greater will be the contrast, while the less employed the flatter will be the results. Strong prints may be secured from weak negatives, and vice versa. For an average negative use 2 dram of No. 3 in each 4 ounces of developer.

A warm black tone will be obtained on some papers by the use of No. 1, while on others it will give a fine dark sepia.

A warm brown tone results from use of No. 2 solution, and intermediate tones are secured by mixing solutions 1 and 2 in the proportion desired.

Developing.

The prints may be developed by immersing them in the developing solution, but it is preferable to float them on the solution, for when the paper is quite thick and porous air-bells will give considerable trouble when the whole print is immersed. Development takes place rapidly, and when sufficient strength has been obtained the prints should be placed directly, without washing, into the clearing solution.

Clearing Solution.

No. 2 (developer) 4 ounces; No. 3 (restrainer) 2 to 3 drams.

When the print has been placed directly from the developer into the clearing solution, the dish containing the clearing bath must be rocked for a moment or two, when the prints may be left in the bath for not less than 10 minutes. If convenient to do so, no harm will be done if they remain in this bath for half an hour. After clearing, the prints should be rinsed in two changes of water and then fixed.

Fixing Solution.

Hyposulphite of Soda 1 ounce
Strong Ammonia 2 drams
Water 20 ounces

The prints should be handled over in this bath for a period of 10 minutes, so as to remove all traces of soluble silver salts which may be left in the paper.

Final Washing.

A final washing of one-half hour completes the operation. Drying may be hastened by blotting off, or by heat, as there is no gelatin coating to stick or melt.

Important Pointers.

• The sensitizing solution should be kept in the dark.
• Never use a brush with a metal binding for sensitizing.
• Prints dry a trifle darker than they appear when wet.
• Bronzing in the shadows appears if printing is carried out in direct sunlight. Thin negatives should always be printed in the shade.

Manipulating Results by Means of the Restrainer (No. 3).

It will be found that the more restrainer added to the developer the greater will be the amount of exposure necessary when printing. By applying this to an underdeveloped, over-exposed negative in other words, a very flat negative the printing should be carried to a considerable depth, and by using from two to four times the amount of restrainer called for when developing a print from a normal negative, a sufficient amount of contrast will result. If judgment is exercised it will be found that this restrainer places in your hands a great power with which to manipulate.

This process is not generally used in photographic studios, yet is employed by a great many commercial and landscape photographers, as the process is inexpensive. The principal advantage of the process lies in the fact that the printing can be done on almost any kind of material. The sensitizing, printing and developing is all done on short order and some very pretty effects can be produced. You must familiarize yourself with the process to appreciate its good qualities. Select for your initial work some ordinary drawing paper and sensitize it first without sizing, making several experiments in this way. After you have become quite familiar with the process, select coarser paper requiring sizing, and size and sensitize according to instructions, making several prints thereon.

A good plan is to size and sensitize a number of different grades and weights of paper. Pulpy paper should not be used for this purpose, as you are apt to be troubled with air bubbles. However, this material may be used if carefully sized before sensitizing, to give the surface a good body. After making prints on all the different surfaces, you will have a pretty fair idea of the process. By noting on the backs of your test prints your observations of the effects of the different manipulations, making particular note of the various qualities of paper which produced the best results, and filing all these prints in your proof file, you will establish a record of valuable information for future reference.