Images negative

In Real Time X-Ray inspection a positive image is used. It takes an operator who is used to the negative image of film X-Ray less than one hour to get used to a positive image. 

Mercaptoselenazoies with Q to C,o cyclic hydrocarbon substituents in the 4-position have been mentioned as giving negative images from photosolubie emulsions (38. 39). Equally cited are other heterocycles such as thiazole. oxazole, or imidazole. 

Schematic diagram showing how placing a thin layer of highly dispersed carbon onto the surface of a metal filament leads to an induced dipolar field having positive and negative image charges. The positive side is always on the metal, which is much less electronegative than carbon. This positive charge makes it much more difficult to remove electrons from the metal surface. The higher the value of a work function, the more difficult it is to remove an electron. Effectively, the layer of carbon increases the work function of the filament metal. Very finely divided silicon dioxide can be used in place of carbon.

Negative image in red-sensitized layer Metallized cyan dye developer layer... 

Figure 9. Cross-section of negative images obtained by exposure to 0.52 mJ/cm2 of 254 nm radiation (130°C postbakc).

Figure 10. Scanning electron micrographs of positive (top, 3.5 mJ/cm2) and negative images (bottom, 3.0 mJ/cm2) heated at 200°C for 30 min (the positive image was re-exposed to 2.8 mJ/cm2 of 254 nm radiation and baked at 130 C for 2 min prior to the 200°C bake).

Figure 11. Cross-section of positive (top, 3.0 ml/cm2) and negative images (bottom, 2.2 mJ/cm2) heated at 200°C for 30 min.

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