Kodak P-255 Photomicrography, Electron Micrography, Astronomical Photography, Laser Photography

Page 5

Photomicrography

The low contrast of most microscopic subjects often requires

acontrast-enhancing film-and-developer combination and (with stained specimens) a contrast-enhancing filter. For routine photomicrography of H and E-stained tissue, try a broad-band yellow-green filter (e.g., a KODAK WRATTEN Gelatin Filter No. 11) at a tungsten exposure index of 50, developed in HC-110 Developer (Dilution B) for 8 minutes at 68°F (20°C). Negatives should print easily and with good contrast on normal-contrast paper. (If negatives are too dense, use a higher exposure index; if too thin, use a lower one. If contrast is too low, increase the development time; if too high, decrease the time.)

For phase-contrast and differential-contrast techniques, try a tungsten exposure index of 100, and develop in HC-110 Developer (Dilution D) for 6 minutes at 68°F (20°C). (If necessary, adjust the exposure index or development as described above.) This method may also be suitable for banding techniques in chromosome photomicrography. When you want maximum contrast, as in older karyotyping methods, use a tungsten exposure index of about 125, and develop in Developer D-19 for 4 minutes at 68°F (20°C). (Because of the differing spectral sensitivities of microscope photocells and the special characteristics of Technical Pan Films, these exposure index recommendations cannot be exact.)

Metallographers can easily select development conditions from the characteristic curves shown in this pamphlet, based on the contrast index they have used successfully with other materials.

Electron Micrography

Use Technical Pan Film to record the output of the fiber-optic faceplate in transmission electron microscopes and to provide optimum contrast and resolution for biological specimens.

Make tests to determine exposures for the accelerating voltage and magnification. Develop for 512 minutes in Developer D-19 (1:2) at 68°F (20°C) or for 4 minutes in Developer D-19 (full strength) at 68°F (20°C). For less contrast, process for 8 to 12 minutes in HC-110 Developer (Dilution B) at 68°F (20°C).

Astronomical Photography

The extended red sensitivity of Technical Pan Films makes them especially suited to solar photography at the H-alpha line (656 nm), and their reasonably uniform spectral sensitivity over the visible region of the spectrum makes them most useful for solar filtergrams. They are also useful for lunar and planetary photography. The extremely fine grain and high resolving power, coupled with high-contrast development (with Developer D-19, for example) permits reproduction of very fine detail on objects in the solar system.

You can use these films for stellar photography, but first hypersensitize them with forming gas or silver nitrate to improve the film response with the long exposures required. (For information on hypersensitization of Technical Pan Films, see the American Astronomical Society Photo-Bulletin,Issue No. 24, 1980, No. 2.)

Laser Photography

The extended red sensitivity of these films makes them very useful in applications in which the exposing radiation is from helium-neon lasers (633 nm) or red-light-emitting diodes (typically 640 to 650 nm).

For example, Technical Pan Films are frequently recommended for photographing holograms reconstructed with the helium-neon lasers. Since the range of scene brightnesses that can be recorded and reconstructed holographically is inherently great, it is sometimes appropriate to process the film to a low contrast (contrast index of 0.5 to 0.6). However, in holographic interferometry, processing the film to a contrast index of 1.5 or more will enhance the visibility of the interferometric fringe by increasing its modulation. Try HC-110 Developer (Dilution B).

In image-recording or plotting applications, you can control the film contrast during processing to convert the modulation range of the recorder to the density range you want on the film.

KODAK PROFESSIONAL Technical Pan Film P-255

5

Image 5
Contents Sizes Available ApplicationsJune 2003 P-255 Kodak Professional Technical Pan FilmStorage and Handling Spectral SensitivityExposure Filter FactorsDarkroom Recommendations Adjustments for Long and Short ExposuresIf Indicated Use This Development Machine Developer ExposurePictorial Photography Specific ApplicationsCopy Applications Microphotography MicrofilmingElectron Micrography PhotomicrographyAstronomical Photography Laser PhotographyLiquid Developer Agitation Technique ProcessingFinal Steps in Tank Processing- 68 to 86F 20 to 30C Tray Processing sheetsOther Kodak Developers Step No. Path Temperature RacksFinal Steps in Tray Processing- 65 to 70F 18 to 21C Processing SequencePrinting IMAGE-STRUCTURE CharacteristicsSpectral-Sensitivity Curves Modulation-Transfer CurvesExposure Tungsten, 1/25 second Characteristic Curves11 min =0.70 More Information Quick Reference Guide to DevelopersCAT 817 Kodak Developer to Use for