Silver intensifier

Silver Intensification Silver intensification has a noticeable effect on low values, which is where thin, underexposed negatives usually need help. It does, however, have the unfortunate habit of staining everything black. Wear gloves and try not to get it on your hands or clothes, but if you accidentally stain yourself, try using the Developer Stain Remover for Hands found in Formulas. Instructions for silver intensification will be found in Formulas Negative Intensifiers Kodak IN-5 Silver Intensifier. 

The immunoreactive processes intermingled in the neuropil represent dendrites. Scale bar 50 pm. In (D), the immunogold labeling of part of an NRD immunoreactive neuronal cell body and of nearby dendrites (d) predominates on their plasma membrane. (E) Immunogold labeling of 5-HT1A immunoreactive dendrites (d) in NRD. The silver-intensified immunogold particles are mostly associated with the plasma membrane of these processes. Note the absence of particles in areas of synaptic differentiation on these dendrites (between small arrows). Scale bars in (D) and (E) 1 pm. (Reproduced with permission from ref. 25.)... 

Fig. 8. CCK in the MOB. A-C. Silver-intensified CCK-immunohistoehemical staining in the main olfactory bulb. CCK-immunoreactive neurons are located mainly in the superficial one-third of the EPL the majority of these CCK-positive neurons are tufted cells. The apical and secondary dendrites of these cells are well delineated in the higher-power micrographs of (B) and (C). Thin axon-like processes course toward the ll L. In addition to the staining of cell bodies and dendrites, there is a dense, uniform CCK-like immunoreactive band consisting of terminal-lie puncta restricted to the IPL. Calibration bar in A = 500 fira, bar in B = 100 /tm, and bar in C = 60 /mi.

The chloride is white, the bromide pale yellow and the iodide deeper yellow. These are examples (uncommon) of a coloured compound being obtained from colourless ions. The silver(I) ion intensifies colour in other cases, for example silver chromate(VI), Ag2Cr04, is brick-red while potassium chromaie(VI). K2Cr04. is yellow. 

The list of intensifier formulas includes uranium, silver, copper, selenium, chromium, mercuric chloride, and mercuric iodide. Some of the formulas, such as uranium, create a high degree of intensification but a low degree of stability. Others, such as chromium, do not intensify nearly as well, but the image is reputedly quite stable. 

Chromium Intensifier Chromium intensifier is a proportional intensifier the amount of intensification is proportional to the amount of silver present in the negative. Therefore, denser areas of the negative are affected more than thin areas. Chromium intensification is useful for increasing contrast since it has little effect on thin, shadow areas. To be effective, chromium intensification must often be repeated several times. 

Sepia Intensification Bleach and redevelop sepia toners, such as Ansco 221 Sepia Toner or Kodak T-7a Sulfide Sepia Toner, are more effective than chromium intensifier and will provide maximum archival protection for your negatives. The reason for the latter is explained more fully in Chapter 10,Toning Prints Protective Toners, though simply put, converting an image from silver metal to silver sulfide makes the image as permanent as it possibly can be. 

I recommend not intensifying with silver beyond 10 minutes, even though Kodak claims it can be used up to 25 minutes. If you do over intensify use two-solution Farmer s Reducer R-4b to reduce or eliminate the silver. 

This produces a brown end product which is highly insoluble in alcohol and other organic solvents. Oxidation of DAB also causes polymerization, resulting in the ability to react with osmium tetroxide, and thus increasing its staining intensity and electron density. Of the several metals and methods used to intensify the optical density of polymerized DAB, gold chloride in combination with silver sulfide appears to be the most successful (6). DAB has been classified as a potential carcinogen and therefore should be handled and disposed of with appropriate care. 

The physical development employed in the silver enhancement procedure was originally used in photographic work, including electron microscopic autoradiography (2,3), and is widely applied today in intensifying... 

---