Wants to withhold description of 'developing' process until it is perfected to obviate others using it. Also refers to second process to make 'positive' and 'negative.'
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Wants to withhold description of 'developing' process until it is perfected to obviate others using it. Also refers to second process to make 'positive' and 'negative.'
Some comments on JH's light and photography experiments, especially effects of different kinds of glass and fixing with ferrocyanate.
Describes mediocre results obtained using ferrocyanate of potash for fixing image. Mentions some other methods, including his favorite, common salt. Asks JH to keep these secret.
More about paper being published in both the R.S.P.T. and Athenaeum.
Finally had success washing with ferrocyanate. Wants to present note of 'his' processes to R.S.L. and so to the world.
Wishes to communicate to J. B. Biot, and so to Academie des sciences, JH's two 'beautiful' fixing methods, by hyposulfite and ferrocyanate.
Questions JH's intent to display 'photogenic drawings' to R.S.L.