20. Tripod

Tripod. The tripod should be firm and adjustable to customary limits of height. In interior photography, the necessary exposure being of considerable length, there must be absolutely no danger of the camera jarring or moving during the exposure. As it is sometimes necessary to work on polished floors, it would be advisable to provide yourself with rubber tips to slip over the sharp points of the tripod feet, to prevent the camera from slipping. A better accessory, however, is three strips of wood, each 30 inches long by 2 inches wide, and 1/4 inch thick. Fasten together with a thumb screw running through one end of each, thus permitting them to be spread out in any direction. Six to ten holes should be bored in the ends of these strips, to receive the end of the tripod legs. When not in use this appliance folds into a very small space for carrying. Tripod stays are procurable through the supply dealer, and with them the tripod is made perfectly rigid and cannot slide; but these do not protect highly polished floors from being scratched by the metallic points at the ends of the tripod legs.

21. Plates To Use

Plates To Use. For all interior work non-halation plates are the best to use, as they tend to prevent halation. Ordinary plates can be used, however, by working carefully. In fact the majority of interiors are made with ordinary plates, and where they are properly employed good results can be obtained; but if treated as an ordinary exposure your results will not be satisfactory.

22. Cause Of Halation

Cause Of Halation. Halation is due mainly to the reflection of light from the back surface of the glass or other support of the sensitive film, or even the inside of the plate-holder. To overcome this, plate manufacturers have placed upon the market the non-halation plate.

23. Non-Halation Plates

Non-Halation Plates. These plates are double coated and especially made to prevent halation. They are recommended for photographing interiors in which strong light, entering through windows admitted into the view, must be contended with. They are first coated with a slow emulsion, and then, for a second time, with a rapid emulsion.

24. Ortho Or Isochromatic Plates

Ortho Or Isochromatic Plates. These should be used when photographing interiors of churches and public buildings, in which are stained glass windows, for, being color sensitive, they will give the true relative values of the different colors.

25. Non-Halation Ortho Plates

Non-Halation Ortho Plates. We have briefly explained the reasons, under the foregoing headings, for the choice of plate best to use for a given purpose. In so doing, however, it was not intended to convey the impression that good results may not be secured with any other brand of plate if used intelligently. The ordinary plate, the non-halation plate and the orthochromatic plate each have their special advantages for particular classes of photography, but there are times when it is necessary to have a plate that is not only non-halation, but also corrected so as to give the best of color values. Many times in making interior views highly colored objects, such as upholstered furniture, draperies, etc., will not reproduce properly, unless an orthochromatic plate be used. At the same time windows may enter into the angle of view, and thus require that the plate have non-halation properties. The Non-Halation Ortho plate and the Isonon plate which are combinations of the two plates just mentioned, are practically universal in their application, and of particular value when photographing interiors where color values and contrasts of light and shade must receive special consideration.