Evening star. [volume] (Washington, D.C.) 1854-1972, 1929-05-14
TELEWS|ON FUTURE
IS HAMPERED BY
MANY PROBLEMS
Economic Factors Remain to
Be Solved, Radio Engineers
Hear at Convention.
DIFFICULT MECHANICAL
QUESTIONS REMAIN
Color Distortion and Inadequacy OF
Images From Public's View
Are Considered.
BY THOMAS r. HENRY.


television can take its place with the
teIephone and radio in every home, IL
was pointed out today at a televlslon
symposium at the annual convention OF
the National Institute of Radio Engi-
neers at the United States Chamber OF
Commerce.
Because of the economic factors in
volved. speakers explained, there Is not
the spur of competition for mechanical
Improvement to make the television ap-
psratus serviceable to the average FAM
ilv. The mechanical difficulties. it was
said, not only are enormously greater
than were met with in the telephone,
but there also is a great gap between
television) and transmission OF fac smile
pictures by telegraph and telephone,
which already is q demonstrated sue
cess, with some commercial application.
Sound and Vision Compared.
"Television transmission is a method
Of communication of intelligence far
transcending in its requirements any
form of facsimile transmission so lar
developed" said Alfred NJ Goldsmith.
vice president of the Radio Corporation
Of America. THE transmission OF an
excellent facsimile picture sent at teie-
vision speeds would correspond to the
transmission of a total number OF dot
elements requiring but few seconds.
The actual facsimile picture sent at
facsimile speeds may require almost as
many tens of minutes. The speed OF
picture element transmission is there
fore in the approximate ratio OF 100
10 for television, as compared with
facsimile
A significant comparison of the trans
mission of a television image and the
transmission of sound. said ]. w. Hor-
ton of the General Radio Co. lies In
the number of units per second. Thus
to send 4-by-5-inch photograph would
require a frequency of 100000 cycles
Der second wide.
Admirable reproduction of any sound
can be achieved by the use OF a ire
oueney. range of 10000 cycles wide. 1t
thus appears that the ratio of the visual
to the audible information received by
the spectator is, as an order of magni-
tlde somewhere in the region of 200 to
1. This figure should be kept in mind
when talking of adding q television
screen to your house telephone, as 1t
gives some idea of the increased in-
misunderstanding capacity. which
plant.
Color Distortion Is Problem.
am television no number can be fixed
as representing a required amount OF
information. A recognizable image may
be secured by ten pictures per second,
each having less than 1000 elements.
Twenty pictures per second, each con-
tanning 100000 elements, Is propably
nearer the performance expected by the
eager public. Somewhere between these
widely scattered limits is the region IN
which subsequent activity VIII be con-
The problem Of color distortion In
television also is bothering radio en-
eineers, Mr. Horton pointed out.
Most photo-electric cells" he said.
fare relatively insensitive at the red end
of the spectrum, and treat any portion
of the image having this color as II 1t
were black. The effect Is most notice
able with yellow. People with yellow
hair are reported by the television sys-
tenn as having very dark hair. At the
other end of the cell the photo-electric
system is relatively more sensitive than
the human eye, and makes little distinc-
tons between green and white surfaces.
This may be demonstrated effectively
by means of a yellow-back bill. At a
distance the eye sees the yellow side
of the bill almost as uniform light
surface. When reproduced by telsvision,
however, this side of the bill appears to
be made up of distinct pattern on a
light ground. The pattern on the green
side of the bill, even at distance, APP
pears to the eye in sharp contrast to
the background, whereas the image re-
produced by the television system APP
pears as a uniform white surface"
Need Extensive Experiments.
"The matter of fixing desirable per-
Torrance limits he continued, will
have to be settled by extensive expert
mentation, which will ultimately come
within the scope of one form Of the
transmission systems and television sys-
TENS, like every other product of In
dustry, will be built to those limits
where the quality of performance OBJ
tanned has a value identical with the
cost of securing it. Scientifically the
problems were all solved years ago.
Economically it is just beginning to
appear that a solution may be pos
eible.
Transmission of still pictures in color
by the facsimile method was reported
by R. H. Ranger of the Radio Corpora
ton of America. This is accomplished
by using receiving apparatus by which
the lines coming over the wire are
recorded on an extremely sensitive wax
paper by a stream of hot air from a
fine nozzle which plays over the paper.
lIl6 oESjIEu llliEs III I1lC
wax by melting. Then the waxed paper
may be linked and reproductions printed
from it, Any color may be used, as di-
rected by the transmitting operator
Several colored pictures, Mr.. Ranger
said. already have been sent across the
continent by this method.
Progress toward realization of radio
moving pictures was reported by c.
Francis Jenkins of Washington. Televi-
sion, it was explained, operates by split
ting the pictures to be transmitted into
elementary areas" over which moves a
pencil of light Each elementary area
Mr.. jenkins explained is lighted only
about 1-2304th part of the whole time
This results in an extremely dull light
ing effect on the transmitted picture
which has been a discouraging handi'
cap.
81 am attacking the problem" Mr.
jenkins said. "by substituting persist
ence of light for persistence of vision
This new princinle Is incorporated in g
radiomovies receiver am now building
In which the light of each elementarz
area persists for an appreciate time
say one-tenth of a second. after the
exciting current has passed on.
This principle will be an important
contribution toward bringing into thu
home the long promised radio-vision re-
ception of inaugural ceremonies. bas'
ball games, flower festivals and bah,