time development for plates is coming into more general use, perhaps a few notes upon the subject, drawn from practical experience, may be found of interest. This method of development would undoubtedly have been generally employed years ago, but like many other good things, numerous theories had to be overcome before photographers could be induced to try it. The investigations of Messrs. Hurter and Driffield have thrown much light upon the subject of development, among other things, the old idea that "tinkering" with the developer after the image appeared, would compensate for errors in exposure, was shown to be false, as correct values or tone gradation in the negative depended upon correct exposure, and any modification of the developer must be made before development was begun. A good account of the investigations of Hurter and Driffield, and others, will be found in The Photo-Miniature, Nos. 56 and 66. From personal experience I believe that the timing method will give better average results on a variety of subjects than the old way of guessing at the proper time to stop develop ment. One of the advantages of timing development will be felt in handling very sensitive iso or ortho plates, which are so liable to be fogged by examination before the ruby light, and of course the more sensitive they are to the less actinic colors, such as deep orange and red, the more danger there is of fogging them, but such plates can be manipulated with as much ease, as an ordinary slow plate, by timing, as they can be placed in a covered tray and developed in total darkness, and need not be removed until development is complete. Another advantage of timing, is the uniform results obtained, which it is almost impossible to get by guess work in the dim light (or should I say darkness made visible?) of the ordinary dark room, and this will be found especially true by those who only develop occasionally, as it is so easy to get out of practice when one depends upon a visual examination of the plate during development. Perhaps the reader will say: I can understand how uniform results can be obtained from correct exposures, but how about under and over exposed plates? Now this is where those who have never tried it are surprised at the results, but as a practical test is the best proof, expose three plates on the same subject, giving the first the correct exposure, the second less, and the third more than the normal exposure, and develop all three for the same time, taking the correctly exposed plate as a guide, and developing it to the desired depth. On examining the other two, the under exposed plate will be found thin but with all the detail the exposure could give, and with a little care in printing, such a negative will yield the best print that an under exposure could give, whereas if development had been pushed beyond the normal time, as is generally done in the hope of getting more detail in the shadows or thin parts of the plate, the result would be a blocking up of both the half tones and high lights, producing a negative which would only give a print made up of blotches of black and white, as is too often seen. The over exposed plates will be found somewhat dense or opaque, but will be found to yield a print of good contrast, only requiring a longer time to print, and if this is considered an inconvenience, it may easily be reduced immediately after fixing, by transferring to a tray of water in which a few grains of potassium ferricyanide have been dis |