Investigations on the Theory of the Photographic Process |
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Abegg Abney absorption acetylene action AgBr alkali alkaline development appears bathed Bellach burner cent Chem chemical reaction chromic acid colour concentration constant CrO3 curve CuSO4 density desensitiser diffusion dilution Eder Eder's Jahrbuch effect emulsion equation equilibrium error experiments exposed exposure ferrous oxalate film fixation gelatin give grain gram gram-molecule halogen Hence Hurter and Driffield hydroquinone hydroxylamine increased inertia influence intensity investigation Journ latent image layer light LogE means measured ment metallic silver method metol mins minutes NaOH NH2OH obtained oxidation oxidising p-aminophenol pentane peroxide Phot photo-chemical photographic photometer phys plate portion potassium bromide precipitated probably produced proportional quantity quinol Ratio reducer retarded reversal salts screen sensitiser sensitiveness sensitometry silver bromide silver halide silver ion soaked solid solution spectroscope spectrum subhalide sulphite Table temperature theory thermostat unexposed velocity of development washed wave-length wiss Wratten ordinary Zeit
Popular passages
Page 3 - Hypothesis states that equal volumes of gases at the same temperature and pressure contain equal numbers of molecules.
Page 60 - E is the exposure, i is a characteristic constant of the plate, termed the inertia, and y is a constant depending upon the development, and called the development factor. The magnitudes i and y are obtained graphically as follows : the densities due to nine successive exposures are plotted as ordinates, and the logarithms of the corresponding exposures as abscissae. A curve is obtained which, for a certain period, is practically a straight line. The point where this cuts the exposure axis gives log...
Page 30 - Law If a plane polarized beam of light is allowed to fall on a polarizer, the intensity of the transmitted beam is proportional to the square of the cosine of the angle between the plane of polarization of the incident light and the plane of polarization that would be required for total transmission of the beam. Malus...
Page 50 - It may be surmised that the number of particles of bromide of silver affected by the light is greatest in the front layer of the film, and decreases in geometrical progression as each succeeding layer of the film is reached, an idea which will be better appreciated when the action of light upon the film is explained.
Page 267 - Before speaking of this subject it is necessary to say a few words as to the nature of the discussion.
Page 89 - ... 1-60 1-90 1-70 FeF 1-52 Fe Citrate 1-54 C6H4(OH)2^ 2-10 C6H4(OH)2o 2-80 Table XVI. " Penetration " oj Developer. By the rate of penetration the time for the reducer to pass through the reaction-layer, 8, is understood. This was studied as follows : — If plates are exposed through the glass-side, the image will lie nearer the glass, and we may expect it to appear — (a) On front first if the penetration of the developer count most. (6) On back first if the greater reactivity of the more exposed...
Page 60 - Z. fp Chem.,' 42, p. 600, " Periodic Contact Analysis." proportionately, the ratio of the densities due to any two exposures is constant, and independent of the time of development. Hurter and Driffield showed that if a geometrically increasing series of exposures be given to a plate over a certain range, the density increased arithmetically. Over this period of " correct exposure " the following equation holds : — D = y log E/i, where E is the exposure, i is a characteristic constant of the plate,...
Page 51 - Nernst assumes that in most cases the equilibrium in the reactionlayer is adjusted with practically infinite velocity compared with the diffusion process. If the length of the diffusion path and the diffusion coefficients are known, in many cases the velocity may be calculated in absolute measure. Now, the chemical equation for development with ferrous oxalate is probably Ag- + Fe(C2O4)2" = Ag + Fe(CjO4)2', *'•*• (met.) one silver ion is converted into metallic silver.
Page 52 - ... which is developable because it has been exposed, and in the course of the reaction this varies from the total amount which has been exposed, and which when developed gives the image Dx, to zero, so that the amount of exposed silver bromide available for development at any time, t, is equal to (D«, — D), where D is the density of reduced silver at the time, t. Therefore, dD/dt = kS = k(Dx — D), which gives on integration 1 , D* If this is written in its exponential form, it is Hurter's equation...
Page 59 - fog " reading was automatically subtracted, and taken from the same portion of emulsion as the exposure. But the formula - log ~: — ~ -~ = K shows that there is a theoretical error in assuming the fog in the unexposed strip is equal to that in the exposed strip. For let A + B = C be total mass AgBr, where A = AgBr changed by light, B = AgBr unchanged. Then rate of fogging = (dD{dt)C = K(A + B) in fog strip, and equals (dDjdt)^ = KB in exposed film. Obviously, fog increases faster in unexposed...
Bibliographic information
| Title | Investigations on the Theory of the Photographic Process Investigations on the Theory of the Photographic Process, Samuel Edward Sheppard |
| Authors | Samuel Edward Sheppard, Charles Edward Kenneth Mees |
| Publisher | Longmans, Green and Company, 1907 |
| Original from | the University of California |
| Digitized | Dec 3, 2007 |
| Length | 342 pages |
| Export Citation | BiBTeX EndNote RefMan |