Photographic Exposure Research Articles

Fluorescence microscopy: reduced photobleaching of rhodamine and fluorescein protein conjugates by n-propyl gallate.

n-Prop]yl gallate (0.1 to 0.25 molar, in glycerol) reduces by a factor of 10 the rate of fading of fluorescence of cell structures labeled with tetramethylrhodamine or fluorescein-conjugated antibodies. Hence, prolonged photographic exposure of immunofluorescently labeled cells in the fluorescence microscope yields images with increased sensitivity, making feasible multiple data collection, as with serial optical sectioning.

Computergesteuerte, endoskopische Fotodokumentation im HNO-Bereich - eine neue Methode

Proper lighting and exposure of color photographs were often the main problem in endophotography. The photographic equipment used for different regions of the body was complicated or troublesome to handle. In most cases, time and many tests were necessary, yet good photographic results were rarely obtained. To facilitate handling and to overcome the numerous exposure problems in photographic documentation an electronic TTL computer flash with autodynamic controlled flash energy was developed at the department of ORL at the University of Freiburg in 1980. With the single-handed endoscopic photographic system and the electronic TTL computer flash with automatic exposure technique, endoscopic photography becomes a simple and successful procedure. Even an unskilled "endophotographer" will be able to handle the described system easily. Getting good photographic results in endophotography is no longer a time-consuming and elaborate procedure.

Measurement of Luminance and Illuminance Using Photographic (Luminance) Light Meters

By their nature photographic light exposure meters measure light level. Given the ASA rating of the film being used and either a pair of F-number and exposure time settings or an “exposure value” indicated by the meter, the scene luminance and illuminance can be estimated.

Crystal structural refinement of Na-exchanged stellerite

Natural crystals of stellerite (space group Fmmm) have been Na-exchanged, therefore becoming crystals which are chemically similar to barrerite (space group Amma). Weissenberg and precession long exposure photographs revealed that the cation exchange does not cause the expected symmetry variation, the exchanged crystals still having space group Fmmm and not Amma. The X-ray structure refinement shows that Na enters the cation sites analogous to those of barrerite and the crystals remains orthorhombic. The Fmmm symmetry is exactly maintained for the framework, whereas it is only statistically maintained for the extra-framework cations owing to the random distribution of Na atoms in those sites, alternated occupancy of which in barrerite is responsible for the Amma space group.

Video-enhanced contrast polarization (AVEC-POL) microscopy: a new method applied to the detection of birefringence in the motile reticulopodial network of Allogromia laticollaris.

A new method is described for recording rapid processes of cell motility in polarized light. The Allen video-enhanced contrast (AVEC-POL) method of polarization microscopy achieves significant improvements in resolution, contrast, and the visibility of fine detail by a combination of novel adjustments to a standard (unrectified) polarizing microscope and video camera. Using the full working aperture of a high-power planapochromatic objective lens and compensator setting of lambda/9-lambda/4, visible images appear lacking in contrast. However, the same images viewed with an appropriate video camera equipped with an electronic offset adjustment can be made to appear with as much contrast as desired, revealing a significantly greater amount of fine detail in the image than can be seen by high extinction visual microscopy alone. At bias retardations between one-ninth and one-quarter wave, the diffraction anomaly observed near extinction disappears. Consequently, polarizing rectifiers are not required with the AVEC-POL method, and images previously requiring photographic exposures of around 20 seconds are sufficiently bright to be registered on the video monitor in 1/60 second. Using an intensity monitor, quantitative measurements of cellular birefringence can be retrieved from live or videotaped images displaying a linear relationship between contrast and phase retardation due to birefringence. The AVEC-POL method also renders accessible to polarized light analysis a number of objects that scatter or depolarize too much light to be studied by high extinction methods. The method is demonstrated on model objects and applied to the highly motile reticulopodial network of Allogromia laticollaris. Rapid motion in close association with microtubules can now be analyzed in greater detail at a significant reduction in the cost of recording.

Space-time analysis of photon-limited stellar speckle interferometry

The standard method of stellar speckle interferometry, in which short exposure photographs are individually analyzed, is not the most general method of extracting object information from the time-varying image intensity. We introduce a space-time analysis in which both spatial and temporal fluctuations are taken into account; the aim is to measure the power spectrum of the image with an increased signal to noise ratio. Surprisingly, our more general space-time analysis does not yield an improved signal to noise ratio at very low light levels.

Establishing representative sample designs with aerial photographic observations

Abstract Low altitude aerial photography of boaters on the Lower St. Croix Wild and Scenic Riverway was examined for utility in determining representative sample size and distribution. During the summer of 1977 a questionnaire effort on the Lower St. Croix was undertaken to assess Riverway Social Carrying Capacity. Questionnaire distribution was undertaken at both purposive and random sites along the river. Additional spatial user information was obtained from several map question responses. During that same summer over 9600 aerial photographic exposures were taken along the Lower St. Croix. Spatial information from both the questionnaire effort and aerial photographs was analyzed with graphic computer output. Differences between the two data collection formats (photography and questionnaires) were examined. Use of aerial photography to determine accurate sample strategies and optimum sample size was explored. A minimum 34 percent reduction in sample size and subsequent costs would have been possible if p...

On the proper motion of small pores in sunspot groups

The possibility of measuring pore positions and proper motions with high accuracy, using time series of short exposure photographs, is discussed. Preliminary measurements of a series covering a time span of 110 min. show that positions of small pores may be defined, and horizontal velocities determined, to within 0″.1, or 30 m s−1, respectively.

The Effects of Miracidial Aging and Dilution of Snail-Conditioned Water on Responses of Miracidia of Megalodiscus temperatus

Miracidia of Megalodiscus temperatus from newly hatched until 10 hr old were tested for their ability to react to Helisoma trivolvis snail-conditioned water (SCW) by contact with return (CR) to agar blocks and by percentage of miracidia reacting to a point inoculation of SCW as determined by a photographic time exposure method. CR to agar blocks containing 1:50 SCW was greatest during the first 6 hr after hatching but declined thereafter. The reaction during the first hour to a point inoculation was lower than during the 2nd and 3rd hr. Results were variable from 4 to 10 hr after hatching with the lowest response recorded from 9 to 10 hr. Miracidial responses to dilutions of SCW were assessed by the same two methods. CR to agar blocks containing decreasing concentrations of SCW declined until at a dilution of 1:500 CR was only slightly above the controls. On the other hand, miracidial reactions to point inoculations of SCW as determined by the photographic method were still apparent at a dilution of 1:25,000, when 12% of the miracidia tested reacted. Thus, the photographic time exposure method gives a sensitive means for detecting altered miracidial behavior to various intrinsic and extrinsic factors.

Determination of lens-aberrations by speckle interferometry

The double exposure photograph of a partial diffusor can be considered to be a hologram of the pupil of the optical system. The angle of incidence of the coherent beam illuminating the object is slightly varied between the two exposures and the four reconstructed images of the pupil interfere, the 'speckle-pattern' being identical in all the images. The authors give the mathematical expression for the intensity in the interference pattern, and show how it is possible to determine separately the different lens-aberrations, particularly coma and spherical aberration. Some experimental results are given and discussed.

In situ antigen localization with fluorescamine-conjugated antibodies: A new method

A simple and rapid procedure for the preparation of fluorescent antibodies with fluorescamine is described. The major advantage of the method is that labeled antibody requires no further purification following conjugation. The utility of the method is illustrated by fluorescent staining of virus-specific cytoplasmic and nuclear antigens, those of vesicular stomatitis virus and adenovirus, respectively. The intensity of fluorescence permits short photographic exposure times, and the stained preparations have retained their fluorescence for more than 9 months.

Neighborhoods of galaxies. II - NGC 4151

view Abstract Citations (44) References (37) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Neighborhoods of galaxies. II. NGC 4151. Arp, H. Abstract The paper reviews information derived from deep exposure and superposition photographs of NGC 4151, one of the original Seyfert galaxies. Attention is given to the connection of the companion galaxy G1 to the southernmost spiral arm of NGC 4151, to the relationship of NGC 4151 to its apparent nearest neighbor galaxies, and to the redshifts of the galaxies neighboring NGC 4151. Photometry of the companions of NGC 4151 and neutral hydrogen distribution in NGC 4151 are considered, and a detailed discussion is presented of the physical association of the discordant redshift companions of NGC 4151. Publication: The Astrophysical Journal Pub Date: November 1977 DOI: 10.1086/155658 Bibcode: 1977ApJ...218...70A Keywords: Galactic Clusters; Red Shift; Seyfert Galaxies; Spiral Galaxies; Astronomical Photography; Astronomical Spectroscopy; Galactic Nuclei; Hydrogen; Photographic Plates; Telescopes; X Ray Sources; Astronomy full text sources ADS | data products NED (21) SIMBAD (14)

Replacement of quarter-wave plates by photographic double exposure for controlled density evaluation

Isoclinics are eliminated by double exposure of a film in the camera of a plane polariscope and by rotation of the coupled polaroids through 45° between the two exposures of equal duration. The resultant photographic isochromatic pattern can be evaluated by interpreting and calibrating as lines of constant fractional fringe orders the sharp boundaries between dark and bright regions seen in a developed high-contrast film negative or the narrow equidensity lines obtained in a developed Agfacontour film negative. Alternatively a developed low-contrast film negative may be copied by contact or enlargement on high-contrast or Agfacontour film. The fractional fringe orders of the lines on any photograph depend on the exposure time, or copying exposure time, and on the coupling angle of the polaroids. Monochromatic light, or white light with blue-sensitive or orthochromatic film, may be used. An evaluated example and error analyses show that discrimination of fractional orders is about the same as in conventional compensation methods.

A high sensitivity photographic technique for studying thermal strain at elevated temperatures

Modifications to a 35 mm camera have permitted the recording of small surface deformations in metal pipe sections at temperatures up to 600°C. A fine grid pattern is applied to the surface and double exposure photographs reveal the thermally induced deformations as moiréfringe maps. Linear expansion coefficients and stress concentrations have been calculated at different positions on the specimen.

A phantom for simulating fast dynamic studies on a gamma camera

There is a requirement for a simple, easily standardized, dynamic phantom which will enable calibration studies to be made on parameters such as time resolution, display intensity and photographic exposure settings. The use of a source, suspended over the camera collimator, as a simple pendulum, has been found to provide a useful dynamic phantom. The period of the oscillation, the amplitude and the source strength can all be easily altered and various physiological studies can be simulated. Its use to simulate left ventricular ejection fraction curves, and an extension to provide a technique for testing physiological triggering systems, are described briefly.

Gray Scale Shifts in Ultrasound Displays

Shifts in the displayed shades of gray were found in the initial evaluation of a gray scale ultrasound display. Quantitative measurements of these shifts were performed. These measurements, along with measurements of scan converter output and photographic exposure time, established television (TV) performance as the major cause of shifts. Random variations in photographic exposure time were shown to cause small random shifts. Recommendations are given to minimize the effects of these shifts in clinical sonograms. To minimize shifts, hardware modifications were made on a similar TV. These modifications substantially improved the TV performance.

OH ‐ Radicals in the lower troposphere

OH has been detected in the lower troposphere by optical absorption of the Q1 2 (A²Σ+, v = O, X²Π, v = O) line at 307.995 nm along a 7.8 km path above Jülich (51° North, 6° East). The detection limit depended on the quality of the photographic exposure and reached 2 · 106 cm−3 in the most favourable cases.OH generally remained below 4 · 106 cm−3, the average detection limit. But on several occasions during the observation period from mid August to November 1975 concentrations up to 7 · 106 cm−3 were observed.

Examining water trees in polythene using a flexible light source

SUMMARYA battery powered flexible surgical light can be used as an inexpensive light source for transmission microscopy through 2 mm thick walls of polythene cups, where it is not possible to use a conventional condenser. With ASA 400 film photographic exposure times are 5–10 s. The illuminator has been used to study water trees in polythene.

Laser light absorption measurements in an interaction-produced plasma column

100 J of 10.6-μ laser energy produced in a 1.5-μs pulse was focused to a 2-mm-diam spot by a 50-cm-focal-length mirror. A plasma was created by breakdown in the 70-ns gain-switched peak of the pulse where the light flux becomes greater than 1010 W/cm2. The plasma column subsequently created in 5–20 Torr of hydrogen by the absorbed light energy was observed by 5-ns exposure and streak photographs. The aspect of beam trapping is demonstrated by measurements of the transmitted light intensity radial distribution and significant energy absorption is shown by the measurement of transmitted energy.

Dynamics of bubbles in field access devices studied using a high speed optical sampling microscope

Dynamics of bubbles in field access devices operated at 100 kHz and 200 kHz have been studied using a high speed optical sampling microscope capable of making a 10 nsec single exposure photograph at a known sampling time with respect to a rotating field orientation. By scanning the sampling time through one rotating field cycle, a series of time-sequenced transient domain configurations of bubbles have been recorded on 16 mm film. The devices studied were commonly used permalloy propagating structures, T-bar, T-X, X-bar, and chevron fabricated on an epitaxial garnet film. From each frame of the 16 mm film, plots of the position of the leading and trailing edges of a bubble as a function of rotating field angle were made. These position plots revealed very nonuniform bubble motion in these circuits. The instantaneous velocities of the leading and trailing edges of the bubble were calculated from the position plots. The results show a large velocity variation in all circuits, the ratio of the maximum velocity to the average velocity ranging from 3.5 for the X-bar to 4.8 for the chevron. Maximum vetocities in excess of that predicted on the basis of the critical velocity for dynamic conversion were observed.