Page 34 - The Wellington photographic handbook

too much. The hand-camera worker can only rarely use it on
this account, and it is hardly practicable for portraiture, except out
of doors. But for all subjects containing colour, where the
lengthened exposure does not matter, such as in the case of land-
scapes, architectural and flower subjects, and picture copying, the
WELLINGTON Iso-Speedy plate and WELLINGTON Light
Filter will be found an ideal combination.
It is a good rule always to focus after putting the screen in
position, to make quite sure that nothing has been shifted in so
doing. The exposure for the plate is ascertained with the meter or
WELLINGTON Exposure Disc, in the usual way, and is then
multiplied by five.

Towards sunset, and at other times if the light is distinctly
yellow in colour, it will be found necessary to multiply only by
two or three. This is a case in which experience alone can be a
reliable guide ; but there is not likely to be much trouble on this
score.

In the dark-room the treatment of WELLINGTON Iso
Speedy plates is precisely the same as that of WELLINGTON
'Xtra Speedy plates. The same developer is used, in the same way.
The same red light will do for both, but in the case of the Iso Speedy
it is even more important to keep the dish covered and not to
expose to the red light more than is strictly necessary.

It will be noticed that the speed numbers of the Iso-Speedy
are less than those of the 'Xtra Speedy. This is inevitable,
as the isochromatizing has a slight slowing action, but not enough
to be more than just appreciable.

There is one caution which it is important to give. If the
best rendering with the Iso-Speedy plate and yellow screen
is
to be secured, the plate must not be under-exposed and then over-
developed. Such a result gives an apparent over-correction,
which manifests itself in a " snowiness " over the scene. Full
exposure, and sufficient but not excessive development are neces-
sary if the plate and screen are to be used at their best.
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