16 



6th. Filter the mercury through a piece of chamois leather, if it 

 should have film or dust collected upon it ; the hyposulphite solution 

 used to remove the colour of the plate in setting, must also be 

 filtered before using. 



6th. Never use the gold solution after it has changed colour, or 

 thrown down a precipitate. This solution requires filtering oc- 

 casionally. 



7th. Do not make the mercury too hot, it will spot the plate, and 

 spoil the picture. 



8th. The direct rays of light must not enter the camera in 

 conjunction with those reflected from the object, the picture will 

 be veiled, and the colour of the plate changed to a thick green. 



9th. If the picture appear clouded, it is probably either because 

 the plate has not been thoroughly cleaned, or has absorbed too 

 much Bromine; in the former case, the plate must be cleaned more 

 carefully, in the latter, the accelerating liquid must be changed, or 

 its strength reduced. If it be covered with a white film, the 

 plate has been exposed to light before putting into the camera, or 

 too much light has entered the camera, which may be remedied by 

 using a smaller diapragm. If the whites have become blue, it is 

 overdone, or the mercury has been too much heated ; if browned, 

 it is solarized. 



COLORED DAGUERREOTYPES. 



Daguerreotype portraits are now frequently met with beautifully 

 colored ; but the coloring is a process requiring great care and 

 judgment, and many good pictures are spoilt in fruitless experi- 

 ments. Several different methods of coloring have been proposed. 

 The simplest mode appears to be that of using dry colours ground 

 to a fine powder, and mixed with a little gum, also finely powdered. 

 These are laid on with a fine camel's hair pencil, taking up very 

 little colour at a tune, and will adhere to the plate by breathing 

 over it ; the picture must be well set. The best colours for this 

 purpose are carmine, rouge, chrome yellow, and ultramarine, by 

 combining which any tint may be obtained. 



Mr. Claudet's method is to dip a finely -pointed pencil in spirits 

 of wine, and taking a little of the colour, which must have been 

 pounded with spirits of wine, and again pulverized in a glass mortar, 

 to apply it upon the plate. This coating must be slight, and may be 

 repeated if necessary ; but if too much is put on, it is difficult to 

 remove : the dry colour is applied on this coating, to wbich it will 

 be found to adhere. 



