The only further question is, how to supply the sary red light,—it being, of course, understood that all extraneous white light is entirely shut out. If the side of the room against which the sink is fixed be an outside wall, there may be made in it, at a height of six inches above the operating table, a window, say two feet long and one foot six inches high, glazed with one thickness of ruby and one of orange glass. Whether this be done or not, a " ruby lamp " of some kind will be required for night work. Several varieties of such are here illustrated ; but we would specially recommend our tor Developing Lamp, which is fitted with a new orange glass, lowing of much more light and yet perfectly safe for even the most sensitive plates. An excellent arrangement when a " borrowed light" can be had is the following : We suppose the wall against which the sink is fixed to be dividing the dark room from another ment which is well lighted. A window is made as before, but in this case it may be considerably larger, possibly two and a half feet square, and need be only glazed with one thickness of ruby glass. Opposite this window, several inches from it, and on the light room side there is fixed an ordinary gas-burner. When the daylight wanes this burner is lighted, and affords the necessary illumination.
In any case there should, if possible, be in the dark room at least one ordinary burner, so that there may be a comfortable light if it be desired to do any work which does not involve the exposure of sensitive films,—for example, the washing up of utensils, etc.
The door of the room should fit light-tight, and there should be an opaque black curtain hung just inside it, so that the photographer may make his entrance and exit without letting in a flood of light.
Any available space on the walls may be occupied by shelves on which to place bottles, etc. Besides this, a useful piece of apparatus is a box which shuts light tight, in which sensitive plates may be placed if it be wished to turn up the gas.
Such is the form which a permanent dark room usu ally takes, and if the student be fortunate enough to have the means of fitting up such a room he will find it most convenient ; but it is not by any means necessary that he should do so. As we have said already, almost any room or closet may be used for a temporary dark room, and this not for the production of second-class work, but for the very best. Or our (Marion and Co.'s) new portable tent and table may be used ; it answers the purpose admirably, and has the great convenience of permitting its being put up in any room, outhouse, or even in the garden or courtyard. It is easily fixed, and as easily taken to pieces and stowed away.
It will be seen that the room which we have described very closely resembles an ordinary pantry ; and, in fact, if a pantry can either be secured altogether, or if one can be darkened for the tie being, when the photographer wishes to operate, there will be com pleted as good a dark room as can be desired. If a room with a sink cannot be secured, it is sufficient to have an ordi nary table, to place under it a large pail or tub to act as a sink, and on it a water-jug to supply the necessary water.
For outdoor work it is not uncommon even in these days to use a tent, and for the amateur this may take the place of the dark room altogether. The tent will be described farther on.