288 Manipulation in the Calotype process. [No. 4. 



of the vessel ; pour off the fluid, wash once with a little distilled 

 water, and add 650 grains of iodide of potassium, which should per- 

 fectly re-dissolve the silver and leave a clear fluid ; should it not 

 (for chemicals differ occasionally in purity) then a little more should 

 be added, until the effect is produced. 



Select the sheets to be iodized, carefully rejecting those in the 

 slightest degree damaged or defective; mark the smoothest side 

 with a pencil in one corner, lay the flannel or blotting paper on the 

 solah board, lay the paper marked side uppermost on the flannel 

 and pin it down at the four corners with the silver pins ; now dip 

 the cotton brush into the iodizing solution, incline the board and 

 commencing at the top of the sheet ; lay on the wash with a steady 

 hand as in laying on a flat tint in water colour painting, taking care 

 that none of the liquid runs, turn the board, and cross the first 

 wash with a second at right angles being careful to obliterate all 

 air bubbles and not to leave an excess of liquid, so as to pool when 

 laid on its back ; unpin and lay the sheet on its back on any clean 

 flat surface to dry. Commence upon a second sheet and so on 

 until the requisite number are finished, which depends upon the 

 depth of the dishes used for washing ; before the sheets are perfectly 

 dry immerse them carefully in dish No. 1, putting them in one by 

 one, and getting rid of air bubbles by blowing, gently agitate the 

 dish for a few minutes, then clmnge separately to dish No. 2, repeat 

 the agitation, re-fill No. 1, with clean water and shift back the 

 papers, and so on changing the water half a dozen times or until 

 the dripping from the sheet cause no precipitate in a solution of 

 nitrate of silver. I generally find from four to six changes in an 

 hour suffice. The sheets should now be of a pale primrose colour 

 of an even tint on the face, with scarcely any trace of colour on 

 the back. 



They are now to be lifted out separately and hung up to dry, pins 

 are apt to tear large sheets, the best plan is to throw them across 

 a wooden rail over which sheets of any clean paper, covered with 

 clean towels have been huug. When dry, they can be put away in 

 a portfolio for use. The whole of this operation may be performed 

 in moderate daylight, and the dry paper may be exposed to the full 

 force of the sun with benefit. 



