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From: THE PRACTICAL PRINTER
A COMPLETE MANUAL PHOTOGRAPHIC PRINTING

By Charles W Hearn, 1874

PORCELAIN PRINTING
SELECTION OF THE PORCELAIN PLATES

Porcelain printing is the most difficult of the three parts described in this book both to the experienced and to the inexperienced printer. I think that if the advice which I will give in the following chapters is faithfully carried out that the difficulty will entirely disappear.

The foundation of porcelain printing depends upon obtaining fine porcelain plates, which is by no means an easy thing to do. A little advice as to the kind of glass the beginner should select will perhaps be of value.

In the first place go to a respectable stockdealer, one who understands his business, for none other than such a one would be likely to keep a good stock, especially if he picked out his goods himself.

Do not accept, in the hopes of making a great bargain, porcelain-glass which may be offered to you at a great discount. Beware of such dealers, for you may be certain that the glass is poor, else they could command and get good prices for it. Generally the stock-dealers purchase it in a large quantity and sell it in that way, and then they do not know what class of plates the contents of their packages may contain, but be certain of one thing, they never pay poor prices for good glass, and when they buy cheaply, they know about what they have got. Then again, photographers look over the porcelain glass, and pick out the best plates, when they go after it themselves, but when they send for them they get what is left after the pickings.

There are various sizes of plates which the beginner should provide himself with, and all of these sizes are either ground or polished, as you may desire to have. The ground plates are intended to be used when the porcelain is to be worked up either in water-colors or in oil; the polished plates more for uncolored work.

The sizes are known as the 11×14, 8×10, 6-1/2×8-1/2, and 1/2, 1/4, 1/6. The larger of the plates are sometimes “extra thick,” although those of ordinary thickness are more used, partly on account of the difficulty of cutting the “extra thick” when necessary, but principally because they are more expensive.

In selecting your plates see that they are flat, and if there is a side that is convex then see if the surface of the glass is smooth, for that is the side of the two which is to be used to print on. If the convex side of the plate is not smooth but rough, as it will be if it is not polished properly, then reject it.

To determine whether the glass is flat or not hold it up before you, and look along the edges of both its length and width. If the plate is a little uneven, and you think that by a little care you can so arrange it on the printing-board that perfect contact will come between the negative and plate, then save it.

Another thing in selecting the plates is to see if they are thick, which is very important, especially for anything larger than a half size, for thin porcelain plates often break from their own weight alone; in fact, always use the best plates selected as per advice given above that you can obtain, and one good step towards success will be taken.

CLEANING OF THE PORCELAIN PLATES

Cleaning New Plates

Wash the plates thoroughly on both sides under a tap of water, and place them for the time being in a rack.

The object of washing them first is to remove all of the dirt which may happen to be on them.

Now, to get the plates “chemically clean,” they are placed in a suitable size tray of photographic ware, which contains a solution made of commercial nitric acid one ounce, water four ounces. Let them remain in this acid bath for a day or so, and then they are ready to be removed and washed for albumenizing.

Cleaning Old Plates

For the purpose of cleaning old dirty plates which have been used before, whether varnished or not, they should first be placed in a bath made of concentrated lye one pound, and water one gallon. Let them remain in this bath until the film will be easily removed by running water, which will probably be in a day or so.

When this time has arrived, then wash well under the tap until all of the varnish and film is removed, and then place them one by one in the acid bath as described above. Keep the old plates in the lye until all of the film is removed, and never place them in the acid until that time arrives.

In placing the plates in either the lye or acid always place them in, as above said, one by one, so as to allow the solution to pass over one plate before another one is placed on it.

Never place large and small plates in the same solution at the same time, unless all of the large plates are at the bottom; for if they are mixed up, first large and then small ones, the weight of the upper plates will cause the unevenly supported plates below to break, and it is also a very difficult thing for the beginner to take them out when so mixed up without breaking a number of them.

It would be a good thing to lap the edges of one plate over another in the solution, as the solution will pass between the plates better.

Both the strength of the lye and acid will need to be renewed every month or so.

Before placing the plates in either the lye or acid solutions scrape the edges of them together, and in the future treatment of them you will most probably derive a benefit, as the collodio-chloride will be more likely to keep on the plate during the toning, fixing, &c.

Ground plates are generally very difficult to clean even if the above advice is strictly followed out, and I very often clean them after they are removed from the lye and washed, and while still wet, by sprinkling a little powdered emery on that side which is to be used for printing, and grinding the surface evenly by means of a flat side of a cork.

Ground plates which have been purchased, and are unevenly ground, can thus be made excellent by a very little trouble.

When the grinding is finished wash them well under the tap, and place them for a day or so in the acid bath.

ALBUMINIZING THE PORCELAIN PLATES

The porcelain plates are now to be albumenized, and for this purpose procure three large fresh country eggs, which you are to crack and carefully let the albumen (the white part) into a large clean china bowl, being careful not to let any of the yolk (the yellow part) of the eggs into it, and if by accident a trifle of it should get in, then remove all traces of it by the use of a spoon.

Pour the albumen into a clean graduate, and note the number of ounces of albumen, and add just as many more of pure water.

The eggs should average an ounce of pure albumen each. Pour the diluted albumen back into the bowl, and then place in it a dozen drops of strong aqua ammonia, and with an ordinary egg-beater beat the whole up to as stiff a froth as possible. This should be well and carefully done. Let settle over night, covering the bowl over with a glass. In the morning decant the solution, leaving the froth in the bowl, into a clean bottle, or another bowl, and filter what you need into a thoroughly clean four-ounce vial, or better still into a tiny tea-urn, which has a nose leading to the bottom part of the ware, for then in pouring the solution out there will be no bubbles, for they are at the surface if there are any at all.

A good plan, whether you may have the toy tea-urn or not, is to let the lower part of the funnel rest against the inside of the vial, thus permitting the albumen to run down the side, breaking the fall of the filtered solution, and thus preventing bubbles from being formed.

Filter through one or two thicknesses of good filtering-paper, and if the albumen is not clear, then filter until it is.

Always keep enough ammonia in the solution for it to continually give forth a slight odor.

I have recommended the albumen solution to be used quite thick, as the film on the plate will not be near so likely to be removed in the subsequent operations of the porcelain print, which is so very troublesome both to the beginner and to the “old hand.”

The plates are now to be removed, one at a time as they are wanted, from the acid and held up to the light, and the edges of them looked at to determine the convex side of them, if there is any; but if there is not, then choose the best of the two sides, and proceed to wash thoroughly under the tap, rubbing the sides and edges of the glass well with a mat, so that the fingers, which are often a little greasy in spite of your precautions to the contrary, may not come into contact with the face of the porcelain.

Hold the glass while it is washing by the edges, or extreme corners, and when it is sufficiently washed take it out of the dark-room (where you albumenize the plates) to see as to whether it is fit to be albumenized, and if it is then give it a final rinse with filtered rainwater (filtered as it comes from the tap), and then carefully pour the albumen solution on the upper part of the plate, midway between the two corners, and let it flow over the plate, first to the upper left-hand corner, then to the upper right, next to the lower left (which is the corner by which the plate should be held), and finally carefully pour off at the lower right-hand corner into another bottle.

Do not pour on but a little more albumen than what will cover the plate, and before using again the small quantity that may have been left after you are through albumenizing, it should be filtered.

Now place the plate which you have albumenized, still holding on at the same corner, either in a rack, or upon two nails, to dry, letting the drops fall upon blotting-paper, so that their fall will not raise a cloud of dust. Permit the plates to dry spontaneously.