C. H. CLAUDY
Developing papers are developed with any good developer, all those which act upon plates to produce negatives giving some kind of results on the. paper. But some are much better than others for this purpose and some unsuitable, among there being pyro. Hence it is advisable to have a special developer for that purpose alone. Now I do not pretend to he able to say which of the various organic developers is the best for paper use. But I do not think there is any question that Metol llydrokinon is the most used for that purpose. This developer is made up in a dozen different formulas, according to the particular wishes of the maker and the kind of prints wanted. For instance, if hard prints are wanted, as in line work or from very weak negatives, the metol may be reduced to a trace, or left out altogether-^aud for very soft prints the proportion of metol may be equal to that of the hydrokinonv :My ownformula, which is an adaptation of several is as follows: : 50 oz. water, temperature 50 F.
. I oz. metol.
1 oz. hydrokinon.
71/2 oz. sulphite soda, crystals. . 121/2 oz. carbonite soda crystals 1.16 oz..bromide potassium.
These chemicals are fully dissolved, in the order named, in hot water, with care that each chemical be
: fully dissolved before the next is added to the water. Particular care should be taken to dissolve the metol first and the hydrokinon second, and not reversed, as if this particular is not attended to the hydroki-non will crystalize out after cooling. Immediately all the chemicals are dissolved, the solution should be bottled, tilling to the neck and well corking them. When they have cooled, the solution will have shrunk a little, and the bottle should then be filled full again. The object of filling them to the brim is to insure the exclusion of air, and if this is carefully done the stock solution will keep for a Song tune-I might almost say indefinitely. I have kept it nine months in this way and found it clear when it was finally used. It is obvious that small bottles should be chosen if the developer is not used up rapidly, so that when part of a bottle is used, there is not much lelt for air contamination. Four ounce bottles are excellent.
To use this developer take one ounce of the stock solution to seven ounces of water for the hard papers and two ounces of stock to six ounces of water for the soft papers. More stock and less water means softer prints. Less stock and 'more water means harder prints. This is exactly the reverse from the effect on a plate. Consequently the softest print can be obtained by using undiluted stock solution.
The fixing bath must be acid; and must contain alum. Whether the acid he organic or not, of the alum plain or chrome does not make so much difference.I have used both with good success, but 'prefer the plain acetic acid bath; the formula for which follows:Water 64 ounces
Hypo 16 ounces. Dissolve thoroughly and then add solution made up as follows:
Water, 10 ounses. I Sodium sulphite-crystals, 1/2ounses' Acetic acid 12 per cent, (commercial) 3 ounces. Powdered alum 1/2 ounce. - lf the acid is not commercial the proportion must be calculated from its percent, which the druggist can probably tell you if it is not marked. I usually buy 36 per cent acid and of course use one Ounce in place of the three which would be Used were the add 12 per cent;
This solution keeps perfectly and can be used until it turns milky, when it should be discarded for ir. sh. An important point, particularly in hot weather work is the arrangement of the trays. They should be in the following order, side by side. Developer, clear water, hypo, and preferably from left to right. If the print is to be wettud down before development, have an extra tray of clear water to the left of the development tray. Another important point is a stirring rod of glass, bent at an angle in the middle and mounted in a wooden handle. The handle is a sure marker of which is the hand end of the rod, and the bend makes it easy to stir up the print in the hypo.
There are several methods of getting the developer on the paper With small work and much developing to do, the easiest is to slip the print into the tray of developer, edge lirst, being sure that it goes under the surface swiftly and without a break in the movement. With larger work and not much to do, it may be wise to empty the developer into a graduate between tach development, lay the exposed sheet in the tray and pour the developer on with the same movement one usee in covering a plate with the solution. But prints as large as 10 x 12 may be slipped into the pan of developer with a little care and practice. To do this successfully, take the tray in the left hand by one edge and tilt until the developer runs toward the left hand. Hold the paper by the right edge in the right hand and the hand under it so it lies flat. Let the left edge of the paper drop into the developer at the same time letting the tray become horizontal, while the right hand lets go the paper. The developer will cover the paper even!y in one sweep. For an 8 x 10 print not less than 8 ounces of solution should be used with this method.
With larger sheets of paper it may be easier to thoroughly wet the paper first and then pour the developer on. Nothing but disaster can be expected in attempting to slip a wet limp sheet into the tray, so if the paper is wet down always pour on the developer from a graduate. The object of the wetting is to cause the developer to run on without stopping. Sometimes the developer makes the image come up streaked, a phenomenon due to impure sulphite of soda; the wetting down of the print will prevent the trouble. With small work, however, wetting down is an evil, as it is unnecessary and quickly dilutes the developer.
No definite time can be set for completion of development. As in a plate the development should be for some particular part, usually the high lights. If the shadows are too black by the time the high lights have their detail it is a sign of under, not over, exposure. Prints usually develop in from ten seconds to one minute, depending on the temperature of the developer, the kind of paper and the amount of exposure. The temperature should not be above 65° F. in summer or 70° F. in winter, and inattention to this point will result in either flat or muddy prints, if the solution is too warm or mealy, over constrasty or weak prints if the developer is too cold.
A few seconds before development is completed, get hold of one corner of the print. When the print has gone far enough, pull it quickly from the developer and souse immediately into the clear water bath-run it through quickly and then dump it into the hypo. Immediately pick up the rod and stir the print up well so that the hypo reaches all parts of the surface. Prints had better be thrown into the hypo face up, in-asmnch as air bubbles can be better destroyed with the rod, but care should be taken that the rod is not used too roughly on the surface of the print, otherwise, particularly in warm weather, the emulsion may tear. The fixing bath is better cold than warm- and a fresh bath is therefore indicated in warm weather-a fresh bath being very cold on account of the action of the hypo and water together, an action, by the way, not at all understood any more than that of sulphuric acid and water, which generates heat without any apparent chemical change.
Prints should be fixed fifteen minutes and turned over several times in that period to insure thorough access of the bath to all parts of the film. But longer fixing does no harm. I have left prints in the bath two hours, while at work on more prints, and have seen no ill results. The Eastman Co. put out a non-abrasion developer which contains iodide of potash, resulting in the prints being turned canary yellow in the development. When this color disappears in the bath fixation is supposed to be complete. I have seen it go in thirty seconds in a clean bath yet they advise the time of fixing given above. At any rate, thorough fixing does no harm and is no more trouble than quick fixing.
After fixation, prints should be washed in running water from half an hour in summer to two hours in winter, and the prints should be kept moving. A pile of motionless prints in the bottom of a tray into which and from which water is running, are not being washed. If the force of the water cannot be so graduated as to keep the prints in motion, stir them up every few minutes with the hand. When washed they should be swabbed off with a tuft of cotton to remove dirt and sediment and then laid out to dry. Face down on cheese cloth, after they are surface dry. is a good method. Personally, I dry on newspapers or blotters face up because I am usually in a hurry and find no difficulty in straightening out my prints by drawing them over the sharp edge of a desk or table.
These are one or two points connected with development it may be well to notice. In cool weather the print may be lifted some time before development is completed, and the finishing of the process watched closely, of course, with the print shaded by the body or screen from any direct light. In warm weather the print with developer on it should be exposed to air as little as possible. Most of the brownish stains in the whites which are the bane of the process, are caused by oxidized developer, either in the hand or in the fixing bath, the print not having been moved about sufficiently.
Hand development of prints can be accomplished by using a couple of brushes, and plenty of glycerine, as in the platinum process, but the brush work must not continue more than a couple of minutes at the outside in cool weather, otherwise the developer will oxidize and a stain result. The print, of course, in that process, should be supported on a piece of glass.
There is a great deal of latitude in the exposure which can be given this class of paper, yet some one exposure is always the best. As a general rule, Velox and papers of its class are under exposed. The blacks are too black and the whites are too white. A more prolonged exposure with the same time of development is wanted. The first time you get a fairly good print, try another one from the same negative with double the time and note that both are presentable but that the contrast of one is greater than the other.
Regarding the surface, the dead smooth and the glossy are a little harder to work than the roughs, as development may leave marks if the solution is not entirely pure. On the glossy paper are often found marks looking like pencil marks, caused by abrasions of the surface. They can be easily removed from the dry print by scrubbing gently with cotton slightly dampened, not wet, with alcohol. The other two remedies are, not to use this paper or to use a non-abrasion developer. If glossy paper is to be squeegeed, be sure the fixing bath is fresh and strong, otherwise the film will not be hardened sufficiently and may stick to the surface of the squeegee board.-" Photographic Times."