New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1895-04-22

range the colorng matter in parallel lines. and to
have put them on a separate sheet Of glass In
stead of on the Photographic film; but he probably
did not originate the main idea which Is the COM
blnation OF colors in a single plate. However this
may be, Mr.. McDonough seems to have gone much
further than any else in adapting the single
screen process the illustration OF books and maya
zines which are printed on slow presses. He was
the clever prestidigtator whose trick was described
the beginning OF this article IL is hardly neces-
sary to add the celluoid sheet which was laid
over the photograph in that experiment mad pre-
vfously beeC covered with colored lines, and that
his transparency obtained from a negative
taken under a similar screen; and II was only when
the red lines on the celluoid exactly covered the
portions that photographed under red' ana
green lay what taken under green and
blue over blue that the observed color effect mashed
out into visibility.
This industrious and skilful genius has found a
way TO rule straight parallel lines in colored inks
or pigments upon a smooth surface. so evenly ana
regularly that he actually gets 800 TO the inch. and
he claims that he double the number fnis
enables him to put red line, green line ma
a blue line side b. side within each one-hundredth
or two-hundreith of an inch. The ruling extends
in the same succession across the hole area; the
same intensity OF hue prevails everywhere, ana
the distribution in point Of distance is mathemati-
cally correct. As consequence of all this pre-
csion the colors blend sufficiently TO deceive the
eye. AS has been mentioned tie cellulod sheet
thus treated practically colorless by transmitted
light and has only q slight iridescent appearance
in reflected light. And on opaque white paper.
similarly printed. the casua observer would md no
evidence of the change. except, perhaps, FAINT
grayish tlnge. But II photograph obtained under
a screen ruled in precisely the same manner should
be transferred a block and the latter be used TO
print with black ink. on this specially prepared
paper Mr.. McDonough believes that he would get
on the page picture as faithfully representing
the colors of the original he does in the trans
parency. II would be necessary that the DlocH
should register accuratey-;hat is. the parts OK
the photograph taken under red lines should ex-
actlv coincide with the red lines the printed
paper and so on This needs very delicate adj
iustment but Mr. McDonough believes it practi-
cable on first thought would say that the
black image should be through the colored lines
and hence that the latter should be printed on a
sheet after rather than before, the impression had
been left by the pilot ographic block But An
thongs Bulletin" in a recent reference 20 inc
matter assumes the feasibility OF getting the de-
sired effect with paper ruled in advance. Already
it is possible to reproduce photographs in book work
bv the 'haif-torle" process. II Mr.. McDonoughs
dream is realized a good printer with Sow press
will give 10 such reproductions the true colorlhs OF
NATURE
IL ought 10 be added, however, that just as in the
three or four processes 50 in the sngescreen
method the hucs fna,y exhibited correspond TO
those Of the original only in general way ana
not with absolute precision and for the 'attainmen'
Of perfection in this respect We may be oDhSed 70
Wal, n While longer. At present it is impossible
10 say whether or rot. in his slmplihed system OF
book illustration NJ. McDonough will set any
nearer 70 the goal but his efforts 10 do so VIII %
eagerly watched by photographers. artists. pub
fishers and scientists.