| 释义 |
orthochromatic, a. Photogr.|ˌɔːθəʊkrəʊˈmætɪk|
[f. ortho- ‘correct, proper’ + Gr. χρωµατικός relating to colour, chromatic.]
1. Representing colours in their correct relations, i.e. without exaggerating the deepness of some and the brightness of others (as in ordinary photography). In mod. use, having a sensitivity which is more nearly uniform throughout the visible range than that of silver halide used alone, but which is relatively low in the red and high in the blue part of the spectrum (cf. panchromatic a.).
The emulsions, etc., orig. called ‘orthochromatic’ were in fact orthochromatic in this mod. sense.
1887Athenæum 26 Mar. 421/1 The colours were purposely selected to test as severely as possible the capacity of the plate used—a Dixon's orthochromatic. 1889Pall Mall G. 21 Aug. 7/1 We want photography to be orthochromatic, or colour-correct. 1890A. M. Clerke Syst. Stars 30 ‘Orthochromatic’ plates absolutely free from colour-preferences can be produced by special processes. 1903A. Payne Pract. Orthochromatic Photogr. vi. 88 Orthochromatic plates possessing additional sensitiveness to the yellow and green rays only may be handled in a red light possessing abrupt absorption... Plates..sensitive to the whole of the spectrum..require to be treated in darkness. Such plates are occasionally termed panchromatic. 1919Conquest Nov. 24/1 Plates known as ‘orthochromatic’ or ‘isochromatic’ are sensitive to some of the greens and yellows... Nevertheless, even with these plates, the delicate greens of springtime, the yellow of the gorse, and many other colours in nature, are rendered unsatisfactorily, while the red leaves of autumn photograph as black [sic]. 1920Jrnl. Franklin Inst. CLXXXIX. 25 In the commercial orthochromatic (sensitive to green and yellow) and panchromatic (sensitive to all colors) plates, the dyes are incorporated in the emulsion and the mixture flowed over the glass plate. 1944Electronic Engin. XVI. 326/1 It is essential to use either an orthochromatic or panchromatic emulsion. 1970Amat. Photographer 11 Mar. 60/1 As positive film is orthochromatic (that is, it is not sensitive to the red component of the visible spectrum), it can be handled under a red photographic safelight.
2. Biol. Exhibiting or characterized by the same colour as that of the stain used.
1899Jrnl. R. Microsc. Soc. 379 Orthochromatic macrocytes which are without nuclei and appear late in embryonic life and in anæmia. 1930Maximow & Bloom Text-bk. Histol. v. 114 In this way erythroblasts arise in which the protoplasm is purely acidophil, and stains a bright pink with the Romanowsky mixture. These cells are called orthochromatic erythroblasts or normoblasts. 1971Cancer Res. XXXI. 505/1 This behavior was paralleled by a shift in the pH of the transition from orthochromatic to metachromatic staining of the nucleus after methanol fixation.
So orthochromatism |-ˈkrəʊmətɪz(ə)m|, the condition of being orthochromatic; orthoˈchromatize v. trans., to render orthochromatic; orthoˈchromatized ppl. a., orthoˈchromatizing vbl. n.
1889Anthony's Photogr. Bull. II. 315 In order to obtain true orthochromatism it is always necessary..to interpose a transparent yellow screen somewhere between the object and the plate in order to cut off a certain proportion of the blue and violet rays, to which the plates still remain relatively too sensitive. 1890Ibid. III. 220 We will give an easy method by which any gelatine dry-plate can be orthochromatized. 1892W. J. Stillman in Nation (N.Y.) 15 Dec. 448/3 ‘Orthochromatism’ avoids the glaring contrasts which used to be made by photography between the color-values of blues, yellows, and reds. 1902P. H. Mell Biol. Lab. Methods xii. 175 M. Monpillard says that, for scientific purposes, he prefers ready orthochromatized plates. 1903A. Payne Pract. Orthochromatic Photogr. iv. 46 This process is termed orthochromatising, and plates so treated are known as orthochromatic or isochromatic plates. 1956E. Mytum Introd. Photogr. Materials iii. 59 Sometimes the word isochromatic..was applied to the earlier orthochromatised emulsions. |