The American annual of photography . BRAKEBILL. 19 My explanation of this phenomenon is that the picric acidforms a compound with the gelatine which when dry is muchmore dense and compact than normal gelatine. That this isthe correct explanation, I believe, and is borne out by thefact that if the gelatine film has been exposed beneath a posi-tive, and afterward treated with the picric acid solution, ondrying the image will be represented by a depression in thegelatine. The exposed portions of the film have becomemore or less insoluble and the solution of picric acid is there-fore unable to pen
The American annual of photography . BRAKEBILL. 19 My explanation of this phenomenon is that the picric acidforms a compound with the gelatine which when dry is muchmore dense and compact than normal gelatine. That this isthe correct explanation, I believe, and is borne out by thefact that if the gelatine film has been exposed beneath a posi-tive, and afterward treated with the picric acid solution, ondrying the image will be represented by a depression in thegelatine. The exposed portions of the film have becomemore or less insoluble and the solution of picric acid is there-fore unable to penetrate the film as freely as the unexposedparts and form the compound mentioned above. It appears possible to utilize a relief image of this naturefor obtaining prints photo-mechanically. The plate in this case should be exposed under a grainednegative instead of an ordinary one and then the image wouldbe composed of numerous small raised dots of very hard gela-tine, which should make a good printing surface, retaining inkreadily. .. 3^; \ , .? , V.«7v 1\ ^l
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1919
