224 Professor Draper on the Process of Daguerreotype, 



The chair in which the sitter is placed, has a staff at its 

 back, terminating in an iron ring, that supports the head, so 

 arranged as to have motion in directions to suit any stature 

 and any attitude. By simply resting the back or side of the 

 head against this ring, it may be kept sufficiently still to allow 

 the minutest marks on the face to be copied. The hands should 

 never rest upon the chest, for the motion of respiration dis- 

 turbs them so much, as to bring them out of a thick and 

 clumsy appearance, destroying also the representation of the 

 veins on the back, which, if they are held motionless, are co- 

 pied with surprising beauty. 



It has already been stated, that certain pictorial advantages 

 attend an arrangement in which the light is thrown upon the 

 face at a small angle. This also allows us to get rid entirely 

 of the shadow from the back-ground, or to compose it more 

 gracefully in the picture ; for this, it is well that the chair 

 should be brought forward from the back-ground, from three 

 to six feet. 



Those who undertake Daguerreotype portraitures, will of 

 course arrange the back-grounds of their pictures according to 

 their own tastes. When one that is quite uniform is desired, 

 a blanket, or a cloth of a drab colour, properly suspended, will 

 be found to answer very well. Attention must be paid to the 

 tint, — white, reflecting too much light, would solarize upon the 

 proof before the face had had time to come out, and owing 

 to its reflecting all the different rays, a blur or irradiation 

 would appear on all edges, due to chromatic aberration. It 

 will be readily understood, that if it be desired to introduce a 

 vase, an urn, or other ornament, it must not be arranged 

 against the back-ground, but brought forward until it appears 

 perfectly distinct on the obscured glass of the camera. 



Different parts of the dress, for the same reason, require 

 intervals, differing considerably, to be fairly copied ; the white 

 parts of a costume passing on to solarization before the yellow 

 or black parts have made any decisive representation. We 

 have therefore to make use of temporary expedients. A per- 

 son dressed in a black coat, and open waistcoat of the same 

 colour, must put on a temporary front of a drab or flesh co- 

 lour, or by the time that his face and the fine shadows of his 

 woollen clothing are evolved, his shirt will be solarized, and 

 be blue, or even black, with a white halo around it. Where, 

 however, the white parts of the dress do not expose much 

 surface, or expose it obliquely, these precautions are not es- 

 sential ; the white shirt collar will scarcely solarize until the 

 face is passing into the same condition. 



Precautions of the same kind are necessary in ladies, dresses, 

 which should not be selected of tints contrasting strongly. 



