Yellow Filter Research Articles

Aerial camera filters and their use with aerochrome infrared

Differences in the color rendition of Kodak Aerochrome Infrared photography have been noticed between the photography from Wild and Zeiss aerial cameras during the years in which efforts have been made to control the infrared color balance on contract photography. The cause of these differences has been narrowed down to the different spectral transmissions of the standard yellow filters supplied with these cameras. The filtration recommended by the film manufacturer is most closely matched by the Wild filter. This report recommends an alternative filter combination for the Zeiss camera which will result in a more “normal” color infrared color response for photography from this camera.

A comparison of clear versus yellow ultraviolet filters in reducing fading of selected dyes

Two ultraviolet filters of polyester film, one colorless and one with a strong yellow color, were evaluated for their effectiveness in reducing fading of wool dyed with selected natural dyes and one synthetic dye. Results showed that clear filters offer no protection against fading for some natural dyes. Therefore, clear filters should not be regarded as a slightly less effective alternative to yellow filters for the protection from fading of museum artifacts colored with natural dyes because, in some instances, they are totally ineffective. When the use of yellow filters is unacceptable because of their distortion of color in exhibition areas, controlling level of illuminance to 50 lux is more beneficial than the use of clear filters in protecting some natural dyes from fading.

A Comparison of Clear versus Yellow Ultraviolet Filters in Reducing Fading of Selected Dyes

A Comparison of Clear versus Yellow Ultraviolet Filters in Reducing Fading of Selected Dyes

Psychophysiology of analysis of connotative decodification: the role of thermic and somesthetic systems in decodification of chromatic stimuli.

We hypothesized that in the decodification of connotative aspects of visual chromatic stimuli the periphery of the body plays an important role. In particular we hypothesized that the decodification process of so called "warm" and "cold" colours is related to a real modification of the temperature of the body which is the basis of the "subjective feeling" and of the attribution of the "emotional meaning" to the stimulus. So we have measured the temperature of the body of 36 female psychology students while they were looking at a luminous screen through spectacles in which filters (coloured lenses) of different colours were placed. Analysis indicated that during the perception of so called "warm" colours a statistically significant increase in the temperature of the body appeared. We observed an enhancement of temperature on the left side of the body during the perception with red and yellow filters and a small increase in temperature on the right side of the body with orange and yellow filters. In the discussion of the results we considered also the role of the cerebral dominance in decodification process of the connotative components of stimuli.

Effects of Yellow Filter Glasses on the Results of Photopic and Scotopic Photometry

I measured the luminosity of a white surface with seven different yellow filter glasses and a photometer with two different sensitivities, which resembled the photopic and scotopic sensitivity of a Commission Internationale d'Eclairage standard observer. When measured with filters GG 400, GG 420, GG 435, and GG 455, there was a small and almost equal reduction in the relative photopic and scotopic luminosities. Measured with filters GG 475, GG 495, and OG 515, there was a more marked reduction in the scotopic luminosities than in the photopic luminosities.

Effect of actinomycin D on Tobacco mosaic virus (TMV) accumulation in isolated tobacco protoplasts under varying light conditions

The effect on Tobacco mosaic virus (TMV) accumulation of actinomycin D (AMD) introduced shortly after inoculation into isolated tobacco protoplasts under varying light conditions was examined. The emission spectrum of the light source contained lines in the visible range and in the ultraviolet band (300–400 nm). AMD absorbed light in the visible (400–500 nm) and in the uv (200–400 nm) ranges. AMD substantially inhibited TMV multiplication in the light, and also when the protoplasts were incubated in petri dishes covered with a black filter that allowed only uv light in the range 260–390 nm to pass. In the dark, and also in petri dishes covered with blue or yellow filters that passed in the ranges 400–500 or 500–600 nm, respectively, AMD stimulated TMV reproduction. The suppression of TMV multiplication in isolated tobacco protoplasts was assumed to be associated with a photodynamic effect caused by absorption of uv light by AMD.

Unilateral intraocular lens. Matching brightness and colour perception against the phakic healthy fellow eye.

A combination of yellow and neutral filters was placed in front of an eye with IOL in order to find a colour and brightness match with the healthy phakic fellow eye. A Munsell standard blue pigment colour target was used as a test. Nine persons with a unilateral IOL were examined. The yellow Schott filter GG 420 was chosen by 2 observers, GG 435 by 5 and GG 455 by the remaining 2. In combination with the yellow filter a Schott neutral filter 0.1 NG was preferred by 3 observers, and each of the neutral filters 0.3 NG, 0.45 NG and 0.6 NG was chosen by 2 observers. The luminance of the coloured test target was measured to be 120 cd/m2 without filters and 86 to 31 cd/m2 as measured through the selected filter combinations.

Chlorosis Lives!— and Slips Through MeSH

To the Editor.— Concerning the commentary entitled Whatever Became of Chlorosis? by Dr Crosby,1I do not agree with his line of reasoning as to what makes the skin green in a chlorotic person. As Dr Crosby first points out, combining the pigments blue and yellow will result in green, as in bruising of the skin. However, when he discusses the possibility of a small amount of melanin—which might appear yellow—over-overlying a blue pigment, he then is discussing the physics of light and filters and not the mixing of pigments. A yellow filter will block the transmission of blue and will allow the transmission of yellow, green, or red. It will not combine with blue to form green as in the mixing of pigments.

Effects of yellow filter glasses on colour discrimination of normal observers and on the illumination level.

Ten healthy young persons wearing yellow filter glasses were examined with the Farnsworth-Munsell 100-hue test using a Macbeth daylight illuminator. Results obtained with (Schott) filters GG 400, GG 420, GG 435 and GG 455 were within normal limits. Using filters GG 475, GG 495 and OG 515 the mean total error score was 123.9, 203.8 and 226.9, respectively, and the test diagram showed a tritan error axis. Illumination of the Macbeth daylight illuminator measured without filters was 1800 lux. Using yellow filters the illumination varied from 1650 to 1500 lux.

A study of unitary light curves of AR Lacertae

During the 1982 - 1983 season, the eclipsing binary AR Lac was observed photoelectrically with yellow and blue filters at Yonsei University Observatory. As has often happened, the light curves show changes in the depth of primary minimum and apparently extraneous distortion outside eclipses. Solutions on the Russell model were obtained; the geometric and photometric elements agree well with those of Chambliss (1976) and Park (1984).

Comparison Between Immature Vitrinite and Solid Bitumen, Green River Formation, Piceance Creek Basin, Colorado: ABSTRACT

A major problem in organic petrography is the inability to distinguish immature vitrinite from solid bitumen. For this study, several samples of coal and solid bitumen, found interlayered with oil shales of the Green River Formation, were collected from three continuous cores. Each sample was analyzed under oil immersion with reflected light, with fluorescence (blue light), and by Rock-Eval. In the uppermost part of the cores, the vitrinite and solid bitumen have identical reflectance values under oil immersion (Ro), and the structureless (nonbanded, noncellular) vitrinite is optically indistinguishable from the bitumen. Observation with blue light reveals some details in both the vitrinite and the bitumen; solid bitumen appears more granular than the vitrinite. With the yellow filter, vitrinite shows some banding and spores are visible. Without the filter, the bitumen has an orange-brown hue, whereas the vitrinite is a bright blue. Rock-Eval analysis indicated a much higher hydrogen index for the bitumen (800-850) than for the coal (400-450). The total organic carbon (TOC) was higher for the coal (50-55) than for the bitumen (20-25). In the cores examined, the vitrinite reflectance changes downhole from 0.20 to 0.55; however, the Ro for the bitumen remains constant. Because reflectance values for vitrinite and solid bitumen can be the same or very similar, a researcher should not rely on reflectance values alone to distinguish vitrinite from solid bitumen. End_of_Article - Last_Page 293------------

The effect of a yellow filter on contrast sensitivity.

Most previous studies have found no visual advantage for the use of yellow filters. This study reports the effect of wearing a long-pass yellow filter on monocular spatial contrast sensitivity under photopic and mesopic conditions. Contrast sensitivity was improved with the yellow filter under photopic conditions but not significantly at most spatial frequencies under mesopic conditions.

Automated Counting of Bacterial Colonies on Spread Agar Plates and Non-Gridded Membrane Filters

The Biotran II automated colony counter was compared with a manual procedure for accuracy in counting bacterial colonies using both spread agar plate and membrane filter techniques. Comparative total bacterial counts of 250 samples (14 food, 124 water and 112 raw milk) were analyzed using the spread agar plate technique. Compared to manual enumeration, the Biotran II was found to be inaccurate for counting bacterial colonies on spread agar plates. Only 60 (24%) and 79 (31.6%) Biotran II counts fell within 10 and 20%, respectively, of the corresponding manual counts. Two samples from each of three river and four effluent sources were analyzed for total aerobic, total coliform, fecal coliform, fecal streptococci and total staphylococci bacterial counts using non-gridded membrane filters. A yellow acetate filter was used to mask the background growth and enhance the target colonies on the membrane filter. However, the method had limited success. Only 12 (20.7%) and 20 (34.5%) Biotran II counts fell within 10 and 20%, respectively, of the corresponding manual counts. Until the effect of background growth can be eliminated, the Biotran II cannot be relied upon to accurately count bacterial colonies on membrane filters.

Design of Ripple-free Multilayer Optical Filters

A simple and fast method of designing ripple-free, broad-band, thinfilm edge filters is presented. It uses a successive refinement procedure for ripple reduction without any special merit functions, and a fast computational algorithm for finding the derivative of reflectance. The design of cyan and yellow broad-band edge filters is taken as an example to illustrate the procedure. The influence of various parameters in the ripple reduction process is analysed. The choice of these parameters at various stages of refinement to obtain a fast-converging solution is indicated. The effect of practical errors in controlling the thickness of the layers on the final product is also studied. The method illustrated here can readily be used for the design of any broad-band edge filter and may be extended for other types of multilayer filter.

Studies on oxidation of benzo [ a] pyrene by sunlight and ozone

The destruction of the carcinogen benzo[ a]pyrene (BaP) by light is well known; laboratory workers are routinely advised to cover fluorescent lamps with yellow filters while treating samples containing BaP. However until recently the mechanism of oxidation by sunlight and ozone had not been studied in detail. Concentrations of benzo[ a]pyrene in urban air are in the range of 5–10 μg/1000 m 3. Oxidant concentrations (predominantly in the form of ozone) are reported to be in the range of 0.01 ppm (22 μg per m 3). Thus a sampling system with a filter paper would filter about 22,000 μg of ozone passing through and collect about 5 μg of BaP for analysis. The effect of interactions of such large ozone concentrations with BaP deposited on the filter paper is reported; data for the oxidation rates for benzo[ a]pyrene coated on quartz surface and exposed to ozone or sunlight are presented. The oxidation products were analysed by thin-layer chromatography and highpressure liquid chromatography. From about eight products detected in these experiments, three have been identified as quinones based on UV-absorption spectrometry and mass spectrometry. Oxidation rates as high as 100% per hour of exposure are observed when less than 0.1 μg of BaP is coated inside the quartz tubes and exposed to ozone or sunlight. Oxidation rates for benzo[ a]pyrene (using tritiated BaP) were determined for two types of experimental conditions. In the first set, tritiated BaP was spotted onto a glass fibre paper and sampling continued for 24 h; the loss of BaP was found to be 88%. In the second set tritiated BaP was spotted at intervals of one hour, for eight hours, while sampling is being carried out and the loss of BaP during the period was estimated to be 50%.

Simultane i.a. Infusion eines Cytostaticums und Natrium-Fluoreszeins zur Darstellung des Perfusionsgebietes

Intraarterial chemotherapy of tumours of the head and neck is performed with the aim of selective perfusion of the tumour area, usually located in the blood supply area of the lingual and/or facial artery. With fluorescein added to the intraarterial infusion of methotrexate the perfused skin resp. mucous membrane area can be controlled and documented using an excitation- and barrierfilter (blue and yellow filter).

Some factors affecting basidiospore germination of Pleurotus sapidus

Basidiospore germination of Pleurotus sapidus Kalchbr. on water agar increased from less than 10% to more than 75% when open culture dishes were inverted and taped onto open dishes of yeasts. Germination on water agar was also increased in a 25–75% CO2-enriched atmosphere but was very low in higher CO2 concentrations. Malt agar alone resulted in more than 80% germination. The optimum substrate pH was 6; values below pH 5 or above pH 7 adversely affected germination. Germination greater than 85% occurred at 2 °C (11 days) to 30 °C (2 days) but was 20% at 35 °C, and there was no germination at 40 °C. Germination was unaffected by light with yellow and red filters. Unfiltered light and treatments with blue and green light significantly reduced germination. Surface disinfectants, except dilute ethanol, adversely affected germination.

Selective Masking and the “Lamp-Phosphor” Problem

Mollon and Polden (1978) have suggested that selective backward masking, the greater masking of central than peripheral items in briefly-presented letter rows by a patterned stimulus, may be due to an advantage conveyed to the peripheral items by the more rapid onset of the short wavelengths emitted by tachistoscope lamps. This suggestion was evaluated by comparing report accuracy under mask and no mask conditions when the tachistoscope fields were viewed through yellow or red filters that eliminated all wavelengths below 510 and 590 nm, respectively. The results showed similar selective-masking effects with both filters. Since selective masking occurs even when the short wavelength emissions are eliminated, Mollon and Polden's suggested explanation for selective masking must be rejected.

Improved Method for Thin Layer Chromatographic Analysis of Mycotoxins

Abstract The author’s previously published multimycotoxin method is improved by a series of changes in the development of the citrinin. Importance of the type of UV lamp and the use of a yellow filter are also emphasized.

Control of excitation in the fluorescence microscope

In fluorescence microscopy image brightness and contrast and the rate of fading depend upon the intensity of illumination of the specimen. An iris diaphragm or neutral density filters may be used to reduce fluorescence excitation. Also the excitation band-width may be varied by using a broad band exciter filter with a set of interchangeable yellow glass filters at the lamphouse.