A Manual Of Photography

286 PRACTICE OF PHOTOGRAPHY. M. Blanquart Everard published a process as his own, in France, and received the compliments of the Academy of Sciences for it, which in no respect differed from Mr. Talbot’s : this, therefore, requires no further notice; but a modification of M. Niepce de St. Victor, and his own application of albumen, must not be neglected. Method of preparing paper with albumen, so that it may be employed dry.—The paper prepared by means of albumen pos- sesses properties analogous to those prepared by means of serum, but in a much less degree : the former, like the latter, may be kept for an indefinite time after its preparation with the iodide of potassium, but after having been submitted to the action of the aceto-nitrate of silver it will not keep good beyond the next day. The impressions obtained by means of the following preparation are admirable: though not so well defined as those on glass, yet they are more beautiful, as the outline is less harsh, and they possess more harmony and softness. We consider this to be quite a triumph for those who exercise themselves in the photographic art. Beat into a froth the whites of eggs, to which a saturated solution of iodide of potassium and bromide of potassium has been added, in the proportion of thirty drops of the former and two drops of the latter for the white of each egg; let the mixture stand until the froth returns to a liquid state, filter through clear muslin, and collect the albumen in a large flat vessel. On tins lay the paper to be prepared, and allow it to remain there some minutes. "When it has imbibed the albumen, lift it up by one of its corners; let it drain, and lastly dry, by suspending it witli pins to a line or cord across the room. The subsequent prepara- tion with the aceto-nitrate of silver is in every respect similar to that above described for the paper prepared witli serum ; care being taken not to dry it between the two folds of blotting-paper untif it has become perfectly transparent. The exposure of the prepared paper to the light in tlie camera is done in the same way, and the same treatment with gallic acid is followed: it will, however, be found that the time required for exposure will generally be four or five minutes. Preparation of albuminous paper for receiving a positive image. __The positive paper prepared with albumen gives impressions somewhat shining, but of a very rich tone, well defined, and of perfect transparency; it is prepared in the following manner :— To any quantity of white of, eggs add 25 per cent, by weight of water, saturated witli cliloride of sodium ; beat into a froth, and filter as in the previous operation,—only in this case leave the paper in contact with the albumen for only half a minute