The daily morning journal and courier., 1907-09-27
COLOR PHOTOGRAPHY AT LAST.
MOst FeasLble Process Yet Advanoed

COnOh HdOIOCINhEh HI Al AAoA' Most Feasible Process Yet Advanced.
 Every photographer has felt that his art would not be perfect until it could reproduce colors. The more beautiful the picture before him the more depely he regretted the limita- tions of his monochronme process. But in spite of the immense amount of experimentation that has been carried on continuously ever since the day of Daguerre no satisfactory method could be discovered. At last, however, we seem to be in sight of goal, for it is reported from Paris that the practical difficulties and deieien- cies of the Lumiere process have been overcome, and all colors can be re- produced or, single plate with one exposure and not much more compli- cated manipulation than ordinary plates require.
 Like many previous attempts, this is based upon the three-color princi- pie. As every child knows eff he has been educated in an up-to-date kind ergarten where color tops are played with), white light can be produced by combination of three primary col- ors. Any number of suitable trip lets can be selected but the most use full is violet, green and red, or rather reddish. orange By combining these and making them lighter or darker any desired color and tint can be ob- tained Since the eye is limited in its delicacy of perception it can be de- celved into thinking colors are com bined when they are really separate. The eye cannot distinguish between separate objects if they are too close together in either time or space. If we place them side by side in minute dots the color also disappears. This is the ordinary process of color print ing used in Illustrating magazines and making postcards. By looking at 8 color print with magnifying glass one can see that it is g mixture of distinct dots of three or more col- ors
 In the new photographic process the dots of color are ade of dyed starch grains, These are nearly transparent, very sail and uniform in size. One-third of tbem are stained i violet, one-third green and one-third red. When the three heaps are mix cd together the color disappears and we have one gray heap. When they are spread out and stuck on glass it Hooks like the ordinary ground-glass plate, transmitting light without col or, though somewhat dimmed. The starch grains are crushed down until they form mosaic and the spaces between them filled with fine charcoal. The plate is then coated with the ordinary silver emulsion, made as Iorthoehromatic as possible.
 The plate so prepared Is exposed in a camera with the glass side next to the lens. The light must then pass through the layer of colored starch grains before it reaches the sensitive lsilver, and is therefore broken up into its three primary colors. Suppose the object taken is tree. The light from it's leaves can pass only through the green spots, for the red and vio- let are opaque to 1t, By the peculiar process of development used this spot covered by the green grain is cleared of It's silver leaving its trans lparent, while the other spots are made opaque by the deposit of silver. Therefore on holding thep late up to the light the spot we are considering looks green.
 The result, then, is a positive and can be used only as a transparency or a lantern slide, But by a different development negative can be pro- duced and positive transparencies made from that Owing to the facts that the color layer must absorb part of the light and that a yellow screen must be used to reduce the excessive action of the violet rays, the time of exposure is rather long, from one sec ond on @ bright landscape to several minutes for a portrait The whole process of development only takes half an hour The natural colors are very satisfactorily reproduced and the grain is so fine as no to be notice lable
 If the process proves to be as sim pie and satisfactory as the first re- lports indicate it will probably be Iquickly taken up, especially by anna teurs, who arc always after something new. The three-color processes here tofore in the market have been dis Eapointing. That requsNng three dif- ferent plates viewed through colored glasses gives beautiful effects, but is lexpensive and awkward. That having parallel lines of the three colors on the taking and viewing plates gives 1 false tints as often as true.-New l York Inlnnnnlcnt