CHAPTER XX. 

 THE PLATINOTYPE PROCESS. 



THIS is a process due mainly to the ingenuity and chemical 

 skill of Mr. W. Willis, of London, England, and is so far pro- 

 tected by patent laws that in this country the original platino- 

 type process can only be worked under license from the com- 

 pany,* and with, for the most part, materials provided by the 

 company. The process has a strong claim on our attention on 

 account of its almost indubitable permanence, the image con- 

 sisting of metallic platinum, and on account of the great beauty 

 of its results under favorable conditions. On these two accounts 

 we think it. right to give at least a brief description of the pro- 

 cess ; but except for special micrographic purposes and these 

 practically of one class we do not put forward this process as 

 eminently suited to the photo-micrographer. Where extreme 

 fineness and definition of detail is a necessity no printing pro- 

 cess by which the image is deposited in the substance of a 

 textile such as paper, can be expected to compete with a pro- 

 cess whereby the image is kept on the surface and prevented 

 from " losing itself " among the fibres of the textile by a 

 surface-medium such as albumen or gelatine. But where 

 fineness of detail and sharpness of outline are secondary, 

 and indubitable permanence paramount considerations, this 

 platinotype process is to be strongly recommended when the 

 negatives are of high technical quality. But unless the 

 negatives are tolerably good in a technical sense, i. e. un- 

 less they show a considerable range of gradation from high 

 light to shadow^ and unless they possess a reasonable amount 

 of " pluck " or contrast, their rendering as printed in platino- 

 type will not be satisfactory nor even tolerable. 



* We understand that this license is now unnecessary. 



