74 Pcqoer Process in Photographij, [no. 1, new series, 
Should air bubbles be present, they will be indicated by that por- 
tion of the paper remaining uncolored. Put in as many papers 
as the tray will hold without crowding. When all are in, remove 
in succession the bottom paper to the top, turning it as you do so, 
this will enable you to see if the whole have been properly im- 
mersed. The dish should be shaken occasionally to prevent the 
papers adhering to each other, which they have a tendency to do, 
and which is shown by light patches where the free access of the 
solution has been prevented. The papers may be immersed from 
2 to 3 hours, and then hung up to dry. 
The best mode of suspending iodized papers is to hang up each 
sheet with two of the American spring c^lips, made of Beech and 
sold in London at 1 shilling a dozen,, they are to be strung upon a 
piece of bobbin or thin cord, and stretched across a room that is 
free from dust, which would soil the papers, — and from strong 
draughts of air, which would tear the paper out of the clip. 
An additional precaution which I found necessary to prevent stain- 
ing is to prepare some strips of new blotting paper, as wide as the 
clips and about J of an inch long, fold these in two, and having 
taken up a paper by tw^o corners, let an assistant drop one of these 
papers on each corner close to your fingers, he then opens a clip 
and you put in one corner of the paper, where the blotting paper 
is, you will find it most convenient to open the second clip your- 
self. A small strip of blotting paper should be placed at each of 
the lower corners to facilitate draining, and prevent an excess of 
the iodizing materials from lodging there, which will be the case if 
this is not attended to. 
When the papers are dry, trim off the half inch in excess of the 
length of the slide from whichever end appears most to need it, 
and put them by in an envelope made of course drawing paper, 
which should be kept in a portfolio, or a tin case made for the pur- 
pose. 
Thus far the operations may be conducted in any convenient 
room, but those which I am about to describe must be carried on 
in a room fitted up for the purpose, and into which no ray of white 
(or common daylight) must be allowed to enter whilst either excit- 
