456 On Sun Pictures. 
beneath. The improved pressure frames will permit half of 
the picture to be examined without disturbing it, which will 
enable the operator to watch the process. When sufficiently 
darkened, it should be removed and fixed as follows. 
10th Operation—Fixing the Positive. 
Take 2 ounces of hyposulphite of soda, 1 quart of clean 
water. Make of these a bath in a tin vessel. Plunge the 
positive picture into the bath, and keep it in for an hour or 
two. The impression will appear to fade whilst in this bath, 
but when dried it will be found to haye regained its tone. 
The colour or tone may to a certain extent be modified by 
the length of time that the picture is kept in the hyposul- 
phite bath. This solution will serve for several impressions, 
and will improve by use. 
11th Operation—And Last Process. 
Remove the picture from the above bath and pass it through 
two waters successively to cleanse it from the hyposulphite. 
It should remain in the last-water for an hour or so. Then 
dry it as before directed, and it is finished. A hot smooth- 
ing-iron passed oyer it will deepen ‘he tone considerably. 
The positive pictures never arrive at the sharpness and 
minuteness of detail which the negatives possess. ‘The latter 
are made more transparent by saturating with white or vir- 
gin wax, and by this means the positives are rendered more 
distinct. The process of waxing, however, is very trouble- 
some. Stains on the fingers may be removed by a strong 
solution of cyanide of potassium. 
T have thus succinctly described my modus operandi, which 
differs considerably from that patented by Mr. Fox Talbot. 
