Stripping Varnishing

negative, paper, titles, negatives, ink, gelatine, signature, transfer and type

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488. Titles, etc., on Negatives. Numbers, titles, and signatures may be added by cutting out the letters from a dense part of the image 2 with a fine-pointed graver, or by writing with a pen on a lighter part. The latter method is pre ferable, being quicker, and the work is of better quality. Instead of writing in ink, which requires the use of a retouching desk, it is simpler to use yellow water-colour which has been thinned to a suitable consistency. The writing is then quite visible by reflection, and can be done with the negative flat on an ordinary table. It is usual to write from left to right, as is the practice of engravers and lithographic draughtsmen, on the negative, turned upside down, making the characters as shown in the accompanying specimen (Fig. 179). After a few hours' practice it is possible to write in this fashion quite readily and without using a specimen.

In the case of negatives made for large num bers of prints, the title is generally set up in type, and printed therefrom on to the negative.' Special rubber type is sold giving an imprint similar to that shown in the specimen. When the letter has been assembled in the type holder, it is printed on a thin part of the negative with a greasy ink. The density of the imprint is increased by dusting over with a little black lead, afterwards brushing off the excess : the lead adheres to the greasy ink and not to the dry gelatine.

Titles to print white on a black ground can also be set up in type and transferred to the negative in various ways. The impression can be made on thin sheets of cellophane with a very stiff ink and moderate pressure, dusting over with blacklead as above while the ink is still tacky. The titles are then cut out, and the printed side fixed to the gelatine with a very weak solution of gum arabic which has been applied on the part to be covered.

The imprint can also be made on lithographic transfer paper with a good transfer ink. The titles, when cut out, are placed face upwards on a pad of damp blotting paper, and covered with some dry blotting paper to prevent their curling up.

After a few minutes the soluble layer of the transfer paper becomes sufficiently moistened, and the printed surface of each strip can then be applied to the gelatine of the negative in the required position, causing it to adhere by pres sure with the fingers. The back of the paper is dried with two applications of dry blotting paper, and the transfer done by pressure with a burnisher. After some time' the back of the paper is moistened with a paint-brush, a corner raised with the point of a penknife, and the paper lifted smoothly off. When the gelatine is dry, the ink impression is strengthened by powdering with blacklead (0. Nyblin, 1916).

Titles which have frequently to be repeated, such as a trade-mark or a signature, can be copied on a contrasty plate or film from the original. The prints can be made on transfer paper or on a very contrasty plate from which the film is stripped, and applied while wet to the gelatine of the negative.

For titles to print black on a light part of the picture, a film negative of the desired text 2 can be transferred to the negative after having scraped off the gelatine from an area to receive it, the title negative being secured with a weak solution of gum-arabic.

In the case of a signature which has to appear in black on a white ground, a method of double printing is generally used. A negative of the signature is made on a contrasty film or plate, any small defects being carefully blocked out on the dense portion, and the sides extended with masks of opaque paper. After exposing the sensitive paper under the negative of the subject, it is then exposed under that of the signature, adjusting the latter to a suitably chosen position, or setting it against stops of thin cardboard cemented to the signature negative.

489. Classification of Negatives. A methodical classification is necessary in order that negatives required for any purpose can be found without loss of time. To this end, all negatives should be numbered and arranged in numerical order. Since negatives of different sizes cannot be kept together without risk of accident, it is advisable, in order to avoid mistakes, to adopt a separate numbering for each size. Each size then forms a series designated by a letter which precedes the number.' An index of the negatives will naturally be carried out differently by a professional, amateur or research worker, classification being according to commercial importance in the first case, whilst technical information is of primary im portance in the last two cases.

Such a file-index, besides containing numerical classification data (negative number, date, type of subject), and particulars of accounts (details of the order, agreed price, amount of deposit, promised date of delivery, amount payable) may also contain any information which is likely to explain the cause of a failure or deterior ation, and any facts which will enable one to profit in the future by the experience gained (camera used, number of plate-holder or chang ing box, lens aperture, plate used, light-filter, lighting, exposure, and any further details). The register may also contain any data which might facilitate the future use of the negative (suitable methods of printing, the best conditions for printing or enlarging, the most desirable method of mounting proofs, etc.).

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