328 RECREATION. 
frame the right angle line thus formed with 
strips of cardboard, forming in this man- 
ner an angle in which the post cards may be 
placed. Each card will then be in accurate 
register. Cut an opening through the thick 
paper of sufficient size to accommodate the 
largest picture to be used, and by the use 
of masks on the negatives it will be possi- 
ble to bring each picture in proper position 
on the card. 
In making a series of exposures from dif- 
ferent negatives, select either a negative of 
the greatest or the least density of the col- 
lection, and from this make a standard of 
exposures, varying the exposure as the dif- 
ferent negatives are denser or thinner than 
the standard selected. It is also advisable 
to have a fixed distance for exposure be- 
tween the lamp or gas jet and the printing 
frame. Adopting such a distance gives one 
known condition, and the only remaining 
condition to be considered is the length of 
exposure, which should be governed by the 
condition of the negative used as related to 
the standard. 
Concerning the manipulation of the sensi- 
tized post cards it will usually be sufficient 
if the directions which accompany the pa- 
per are intelligently followed. Much of 
the success in the technical side of photo- 
graphy consists in following implicitly the 
formulas given. 
There will doubtless be found many 
friends who will wish to have post cards 
made from favorite negatives, and in such 
a case a means of money-making is at once 
afforded—Chas. E. Fairman, in The Cam- 
era and Dark Room. 

TO MAKE PYRO DEVELOPER. 
I should like to inquire through REcCREA- 
TION of R. Wadhams, M.D., Wilkes- 
Barre, Pa., what formula he would rec- 
ommend for making pyro developer, and 
how to size such developer. 
I read his article in November REcREA- 
TION entitled, “Why the Amateur Should 
Use Pyro,” and was much interested in it. 
I have been using Stanley plates of late, 
but I have trouble from pin holes in them. 
I dust the plates with a soft camel’s hair 
brush before and after exposure, as recom- 
mended by the plate company, but I get 
pin holes just the same. Can you suggest 
any way of preventing them? 
W. D. Lewis, Lynn, Mass. 
ANSWER. 
My developing solutions are as follows: 
A.—Pyro, I ounce. 
Saturated solution of oxalic acid, 2 
drachms. 
Water, 16 ounces. 
B.—Sodium sulphite, T 80; or : 
Crystals, 10 ounces, or dry, 5 ounces. 
Water, 30 ounces. 
C.—Sodium carbonate, T 40; or 
Crystals, 6 ounces or dry 2% ounces. 
Water, 30 ounces. 
Use 1 ounce of each,-A. B. C. Water, 
7 to I2 Ounces; or use: 
A.—6™% drachms, water, 7% to 12% ounces. 
B.—6_ drachms. 
C.—1 ounce. 
v By using this 3-solution developer, I can 
make up any mixture to correspond to the 
formula given by any plate maker for his 
individual plate; always remembering the 
following rules: Too much pyro chokes 
up the whites and gives too much contrast; 
too little pyro gives slow development and 
lack of contrast. Too much sulphite gives 
blue negative; too little, a brown negative 
and stain. Too much soda makes fog, and 
dense, flat negatives; too little makes con- 
trast and slow development. Addition of 
water mares negative in high lights and 
gives detail; less water gives contrast. 
Hence I vary the preparations according to 
the kind of negative I want. 
In regard to bubbles, I never wet the 
plate before developing. I try to pour the 
developer over the whole plate with one 
motion. I have few air bubbles. 
As regards pin holes, I doubt if dust 
plays so important a role as is supposed. 
It is an easy excuse for those manufactur- 
ers who make dirty plates. Try dusting % 
of the plate and see if you can tell, after 
development, which half was dusted. I 
suggest that Mr. Lewis try another make 
of plates. 
R. L. Wadhams, M.D., Wilkes-Barre, Pa. 

After my exposed plates have been laid 
away some time the film side becomes 
frosty looking. This appearance can be 
readily corrected by soaking the film in 
pure water, and while immersed using a 
camel’s hair brush gently over the emul- 
sion. Will you please state cause of this 
appearance and remedy? Have always ta- 
ken great care with original washing. 
A. N. Wolff, St. Paul, Minn. 
ANSWER. 
In all probability the white deposit you 
find on your negatives is sodium hyposul- 
phite which was not completely washed out. 
To test it make a stock solution of potas- 
sium permanganate 20 grains, sulphuric acid 
I drop, water 2 ounces. Dilute a small 
quantity of this solution with water until 
the color is light. Add to this the water 
in which the negatives were washed to re- 
move the white deposit; if it is hypo the 
solution will lose its color. The remedy 
would be to wash the negatives longer in 
running water. 
If the negatives were stored in a damp 
place it is possible the deposit is a mould. 
—EpIror. 
Eo 
