Apparatus for a Field IVorker 99 



that are useful to the nature photographer. 

 These are : the ordinary fast pLate, of which 

 Seed's 27 or Cramer's Crown are prol^ably the 

 best examples ; the Iso- or Orthochromatic plate; 

 and the Non-halation plate. The first is a plate of 

 fast emulsion, with no j^articular quality, useful in 

 all ordinary cases, and up to within the past few 

 years the best plate on the market. The isochro- 

 matic or orthochromatic plate is one that is coated 

 with an emulsion made especially sensitive to the 

 reds, greens, and yellows, and therefore gives more 

 accurate color values. The non-halation plate is 

 one which prevents, by a double coating of the 

 emulsion, blurring around strongly lighted places 

 such as the window of a room looked at from the 

 inside. There is also a plate, which has lately 

 been placed upon the market, which combines 

 these two cjualities and which is called the non- 

 halation orthochromatic plate. This is, to my 

 mind, the finest plate that has ever been manu- 

 factured, and is most excellent for every style of 

 work. 



For fjeneral use I should recommend the ortho- 

 chromatic plate as giving the best results under 

 all circumstances. It is made in three grades : 

 fast, medium, and slow. The slow gives the best 

 color values, but cannot be used for instantaneous 

 work. Ordinary plates will do well enough for 

 snap-shot work and are easier to manipulate in the 



