In procuring your carbon tissue order at the same time a packet of Single Transfer Paper, which is paper with a thin coating of hard gelatine. Now to proceed. Place a piece of single transfer paper into a dish of cold water, and in three or four minutes the coated side will feel slimy, then place in the same dish a piece of the printed tissue face upwards. This will probably curl up at first and afterwards flatten out again. When this has happened or in a few minutes after immersion bring the piece of single transfer paper and the print together, film to film, so that they may be in contact, and square one with the other. Now holding them by one edge, withdraw them together by sliding them out of the dish on to a sheet of thick glass, a large cutting glass serves well, or stout sheet of zinc.
This should be supported in readiness at the rim of the dish.
Having the transfer paper and print now on the glass or zinc, hold them firmly and with a rubber squeegee press them closely into contact, squeezing as much water out as possible.
A better way perhaps is, if the dish is large enough, to place the glass or zinc under the two papers whilst in the water and so raise them out.
The squeegeeing must be done thoroughly, firmly, and all over—several strokes being given in each direction.
Next lift the papers, now in firm contact and sticking together, and place them between blotting paper on which is a heavy weight. The next print may now be proceeded with and so on.
The print should be between blotting paper and under pressure for about twenty minutes, after which it is removed to a dish of hot water—almost as hot as the hands can comfortably bear, say 100° to 120° F.
After lying in this for a few moments the dark pigment will be seen to be oozing out from between the two papers. When this has begun to come pretty freely take one corner of the print and pull it away from the transfer paper. It should come quite easily, and on being peeled off entirely it is thrown away. We have now the transfer paper bearing the printed film reversed, that is, the side which was previously at the bottom and next the original paper support, is now uppermost and can therefore be got at.
If we splash it or lave it with the hand, using the hot water, we shall soon see what happens. The smudgy mass of pigment begins to wash away and the picture gradually appears.
This constitutes development and we continue working it with hot water until the whole is clear and bright, being careful not to touch the film with fingers or anything but water, for being in a very delicate and soft condition it would be certain to sustain injury.