Evening star. [volume] (Washington, D.C.) 1854-1972, 1902-10-11
Some Hints on Developing.
Ry permission of Harper & Bros.)

uby PERMISSION or Harper & Bros)
After a sensitive plate has been exposed
in the camera to the action Of the light, the
change which has taken place in the sill
yer salts with which it Is coated is invisible
and in this state the picture is called the
patent image, because 1t Is hidden or dor
mant. In order to bring out this image the
sensitive plate is placed in solution which
acts on it in such way that 1t forms an
opaque compound with that part of the
salts which has been acted upon by light.
After the image Is completely formed, the
plate is placed in another solution, which
dissolves out all of the salts which have
not been acted upon by the light, leaving a
reversed image of the objects which were
impressed on the plate-that If, the objects
which were light appear dark, and those
which We're dark appear light. This re-
versed image Is called the negative, and
in order to obtain a correct picture a piece
of sensitive paper Is placed next to the
coated side of the plate, the two placed in
frame and exposed to the light until the
image Is impressed. or printed, on the pa
per. This picture is called the positive.
The different grada tons of light and
shade in the picture are due to the fact
that while all bodies radiate or reflect light
some reflect it much more than others
Those objects which reflect light the strong
est impress themselves more quickly on the
sensitive plate, so as we watch the chemi-
cal change which takes place on the sensi-
tive plate under the action Of the solution
which brings out the image, we notice that
black patches appear here and there on it's
surface. These are the objects which re-
fected the strongest rays of light.
Where the action of the light has been
the strongest the glass will be covered
with black deposit. while parts which
have not been acted upon with much force
Wlll-When the plate has been placed in the
bath which dissolves out the unused salts
show almost clear glass.
If picture has been made of a land
scape. the strongest rays of light come
nd yxha fhor MI 70 l., ,o1oo
in the developing solution the sky will be
the first part of the picture to appear The
other objects will come out one after the
other in the order in which thew reflected
light while all the different lights and
shadows show just how much each reflected
the rays Of light.
The process of developing negative
would be very quickly and easily mastered
If the exposure Of the sensitive plate was
always timed correctly. Correct exposure
Is the exception rather than the rule and
10 get good negatives the amateur must
learn to distinguish between a correct and
an incorrect exposure, and If Incorrectly ex-
! posed, how to treat the plate in order to
preserve the image which has been i'm
pressed upon it.
Simple Development.
The first directions for development will
not be for the kind Of pictures which the
beginner usually takes, but the kind he
ought to take-that is, plates which have
been exposed the exact time to make a
perfect negative.
The picture being made, mix the devel-
oper in the glass graduate. Remove the
plate from the holder. and lay it, film side
up, in the developing tray. Turn the de-
veloper quickly over the plate, taking great
care that the whole surface is flooded in
stantly. II the developer is not applied uni
formly, patches will appear the mega
tive which print darker than the rest Of
the picture; the dark spots being where
the developer did not reach the plate as
quickly as 1t did the other parts, and,
therefore, they are under developed
AS soon as the developer has covered the
plate move the tray gently to and fro,
tipping it from side to side. but not enough
to uncover the plate. This Is called rock
ing the tray" In about half minutes the
high lights will begin to appear.
High Lights.
The high lights are those parts of the
plate which have been exposed to the
strongest light and which viii show white,
or light. in the printed picture.
We will suppose the picture which is be-
ing developed to be that Of landscape
The sky, which has reflected the strongest
light. will appear first. It will show as
black patches here and there at one edge
Of the plate. By the time the sky Is well
out other objects will begin to show. Those
the longest In appearing. After the image
Is well defined on the plate, lift 1t carefully
from the tray and look through II toward
the light, holding 1t rather near the lantern |
in order to see IL the detail Is well out.
Detail.
To explain what Is meant by detail we
Will suppose that there is mass of shrub-l
berry In the picture. II this part Of the pic
ture is developed far enough. the lights and
shadows and forms Of leaves. etc.. Will
show when the plate Is looked at against
the light; but il the glass IL still clear.
there is no detail and the development has
not been carried far enough: 1t must be
put back into the developer and allowed to
remain longer.
When the plate has been sufIieiently de-
veloped. which win be In from three to iive
minutes the yellow color WIN begin to
fade and the outlines whirh have hnas4