COMBLIKE MARKINGS ON THE NEGATIVE. _To the_ EDITORS.
GENTLEMEN,—Perhaps the following may explain the defect “J. H. M.” speaks of:—During the hot weather last summer, while photographing an engine in the open air, every plate showed comblike marks at one side of the plate. After two days’ trial, and filtering the bath, changing the collodion, &c., it struck me that the cause might be the partial drying of the film. A piece of wet blotting-paper at the back of each plate at once remedied the defect, and all came right. I now always place wet paper at the back under similar circumstances.—I am, yours, &c.,
_77, Cannon-street, E.C., January 26, 1872._
GENTLEMEN,—In your useful little ALMANAC for the present year there is an article by Mr. A. L. Henderson, enthusiastically written, in favour of fuming.
Now, in accordance with his recommendation, I have tried the said fuming; but my first essay has certainly not impressed me very strongly as regards its favourable results—whether from my own defective manipulation or not I cannot say.
I found that the paper—especially some of Marion’s thick Saxe—assumed a most disagreeable yellow colour after fuming, and it maintained that colour through all subsequent operations—as a matter of course, spoiling the prints. Another sample of (Rive) paper procured from another dealer was not quite so faulty in this respect; still, in neither case was the brilliancy of the prints enhanced—rather deteriorated, I thought—although Mr. Henderson maintains so stoutly the advantages of fuming in this respect. Again: instead of the toning being quicker and more regular in action, as Mr. Henderson states, I found it much the reverse.
I think that I must be wrong somewhere in my working, and I wish to ask your opinion or Mr. Henderson’s on the best mode of proceeding—assuming it to be really worth while to adopt fuming. I used an oblong box about two feet in length by one foot in breadth, placing at the bottom a narrow-necked bottle containing about two ounces of liquor ammonia, fuming two quarter-sheets of paper for about ten minutes, with the result above stated.
Have I omitted any necessary addition? or have I proceeded wrongly?—I am, yours, &c.,
GENTLEMEN,—In my communication to the Journal last week, at page 37, under heading _Using the Substratum_, there is an omission which would prevent the successful coating of the plates.