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Thomas Cradock Hepworth Sir William Crookes.

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— A. Ti/ro, We have found the following a very good plan for
packing up glass negatives. Take a sheet of fine smooth paper
nn inch each way lar^r than the glass, place it on a perfectly
flat table (on several sheets of blotting paper), and lay the nega-
tive face downwards on to it. Now fold the edges of the paper
over the back and pasto them down, taking care to have the
paper stretched tightly over the face of the negative. The
picture will now be secured against scratches, and the glass may
be packed up in any desirable manner so as to guard against
breakage.

Waxed Paper. — P.- Q. Raymond. We have latterly been
trying to remove the granular appearance which this paper
sometimes has, by soaking the plain paper (English make), be-
fore waxing, in a mixture of one part strong hydrochloric acid
and six of water. After remaining in this bath for an hour,
remove it and wash several times in clean water, then dry and
wax as usual ; this, besides freeing the paper from spots, renders
it beautifully transparent and quite firee from granulation, but
is very tedious and rather difiicult to perform on accoimt of the
rottenness of the paper and the washing required to remove the
acid from it. Where a little extra trouble is not minded to
ensure good results, we can recommend this mode of pro-
ceeding.

TO CORRESPONDENTS.

%* OttT nej:t number will contain a fuU description of the Editor's new method
of printing photographs direct on to wood blocks for engraving purposes.

T. N. S. — Poor % satarated eolation of hyposulphite of soda on the gUss phUe;
allow It to remain until all the yellow Iodide of sUrer has diaiq>peared ; poor
the solution back again into the bottle, and then wash by pouring several
qnarts of water over it^ allowhig some to remain on the plate for ten
minutes, and then pouring more water over the plate.

W. S. B.— It will be impossible for 3'ou to make a small quantity of protosnl-
phate of b'on as pure as you can purchase It, and at as low a price. Ton
will succeed bett with dilate lolphailc add and sidphide of lrou.f



R. P. — We hope, In a few nombera, to be aUe to give soma informatioa
respecting the stoves.

A H. W.— Received.

P. Q. (Seven Oaks).— Try the formula at vol. I p. 86.

Antiquabt,— Should have told us what size the jdcture was required to be.
We can only raggett now a whcde or half-plate portrait lena. Wo do not
tliink that any patent stands In the way of the experiments referred la.
The lens Is worthless in a photographic point of vl^w. Wc think the calo-
typa dieaper than the collodiott pit>oe«. The otber suggestions are receiretl
with thanks, and shall be att^ided to. We wodld willingly open our
columns to "Antiquarian Photography;" will our correspondent commence
the snbjcct by favouring ns with a few notea on the subject?

Amok ScinrruB.— The sntiileet of photographing by means of the electric U|rht
is one which has frequently occupied the attention of scientific men ; we
onrselves hsve tried many experiments on the subject Its great expense,
however, and the anoortatn charactnr of the light, will, we fear, prevent
its coming into much ose vntil great improvonents are effected in the appa-
ratus necessary for its production.

W. U.— Send an address, and we wUl commnnlcate with yon on tbo subject.

Silicon. — It would be hopeless for toy one who has only a knowledge of th*
mechanical part of glass grinding, to attempt the construction of a portrait
combhiatlon. Very high mathematical skUl is required.

Pboxotkb.— L Filter through a doaUe dUckneas of Hitering p«per. and poar
the filtrate back again once or twioe; it will than come throuf^ dear.
3. Add a few grains of cadmimn filings.

Halctost.— 1. Place the camphor hi the clear filtrate. 2. Animal charcoal is
preferable. 8. Yes. simply draining it 4. Only once. 5. Throw it away.

C. H. P. — We do not think the stamped card-board mounts for stereoscopic
paper transparencies are to bo obtained In England.

J. T.— No practical process has yet been described.

G. H. W.— By all means attempt to prodnoe a good negative at once : Intenn-

fying a positive does not give very perfect pictures, and it is far more

trouble.
TrrRATHioma— Bee page 180.
W. G. P.— Our expanding camera has a body similar to an accordion; we

have tried severed, and think this plan the most perfect
T. P. CL— 1. The process you mention is a very bad one, nnd vrtll never give

you satlsfitctory resoltsi 3. Albumen, 1 dunce; chloride of ammoniom, 12

grains. 8. Na 3 is in type now, and can be procured Uuroogh any of our

agehts.

D. N.— TIM plan yon suggest wIU answer v«ry well, bnt In tbat ciae the
ordinary ooUodion process may be used instead of ooUodio-albnmen. T<»
print a transparent positive on a collodio-albumen plate, it Is only reqaisitc
to press the negative and sensitive plate hi contact, and expose to day or
lamp light for the proper time (which must be found out l>y experience),
and then to proceed with developing and fixing, as previously recommended.

F. V. B.— See answer to O. H. W.

Abbstawx. — We will endeavour to give a short account of the waxed paper
process shortlv. We once wrote a pamphlet on the subject, which wu
published at Chapman and Hall's. Try ^igiish plKHograpUe paper, soaked
iu hydrochloric acid, as recommended above.

OxK or Dsvoy.— A friend of oars, a OomishrMm^ and an ardent photographer,
Intends shortly to visit Exeter, and la anxious for an latrodaction to " One
of Devon." Have we permission to divulge our oorrenroudent's address ?

P. ASD A H. SicrTH.— We most know all particulars before wo can do as
yon request.

J. HoLBOYD.— We do not know by what particnlar part of the |at>ce«s
the transparent enamel photographs mentioned in oar last number are
takot Perhaps some of our correspondents wiUfiavoocns with infonnatlon
on tills pohit

J. F. M.— Can yon not tell how the cement is made? Is It Indian rubber in
benzol? We should like to have one of tiie labels. Many thanks for your
polite wishes. We have two agents in Abordeen, and sbonld Uke to estab-
lish an agency at Dundee, if you can flavour as with the name of any person
who would become one.

Stbbeo.— A camera with twin lenses 8} indies ^mrt

P. M.— L The same thing. 2. Explained in an early number. 8. Very diffi-
cult without special apparatus. You would not lie able to manage it without
going to some expense. 4. Accent on the to^. 6. We prefer thon.

J. MouLK. — ^In onr next

AsnnB.— The infimnation required on the subject of Photomphic Societies,
will be found In the *' Photo<jbap«ic Nbws AucAarACK,'^ which was pub-
lished with No. IL We have hardly decided, but we think six months.
Our correspondent ooncludes her letter with the following reeipei, whieh
will, doubtless be of use to many of our readers this weather: — Photographic
Remedy for Chilblains. If when they begin to be troublesome a Ifttla
uniodised collodion be poured on, the ether evaporates, and leaves a thiii
insoluble coating, which prevents the skin flrom breaking, keeps off the air,
and effectually cures them.

Communications declined with thanks:— W. H.— J. M.— Old Hypa— F. W.
W.— John.— Seacole.— T.

The information requh^ by the following correspcHndents is either such as we
are nni^le to give, or It has tq)pearod in recent numbers of tfie " Photo-
OKAPHic Ntws:"— A Novioet— A F— J. L. M.— O. W.— MephistophBes.—
B. a P.— a S. U— O. E, N.-A Young Beginner.— O. a a— Laura.— a IL
K. O.— Xmas.

Ijf TTPBt-JlomuL— J. M.-T. Warwick.— H. 0. J.— P. C.— Viator.— B. W. H.
— J.T.— H. a L— S. as.— H.T. T..-Oneof Devon.— W. H. Vi.-C F. B.—
T. B.— An Amateur.



On account of the Immense number of Important letters we receive, we cannot
promise immediate answers to queries ttf no general interest



*«* An editorial conummkations shonld be addressed to Mr. Cnoons, care
of Messrn Petter and Galpbi, La Belie Sanvage Yard. Private iettan tor th$
Editor, if addressed to the office, shoidd be marked *' private."



THE PHOTOGRAPHIC NEWS ALMANACK betog nearly out of print,
persons desirous of possesdng this popular work are requested to forward
their orders Ipimediately to Messrs. CasseD, Petter, andOalpih, Piioto{;safiixc
News OiBoa, La Belle Souvage Yard, Lodgate HIIL



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THE PHOTOGRAPHIC NEWS.



Vol. L, Na 17.— December 31, 1858.



PHOTOGRAPHY APPLIED TO ENGRAVING
ON WOOD (XYLOPHOTOGRAPHY).
Is accordance with the intention expressed in a previous
nnmber, we lay before our readers a description of a method
we have devised for printing photographs direct on to wood ;
but before we describe our mode of proceeding we will offer
a few remarks on wood-engraving, which may be interesting
and instructive to most of our readers.

The art of engraving wood-blocks is coeval with the inven-
tion of printing ; indeed, it would liave been strange if it
were not so, as the art of engraving letters in the old block-
books would have suggested that the same process might be
employed in reproducing figures of men and animals, and the
rest would follow with improvements of the art. If we may
assume that the date which the oldest engraved block in ex-
istence bears is correct, the art of engraving figures on wood
was practised previous to the discovery of the art of printing.
The block we refer to is that known as the "St. Christo-
pher," and bears the date of 1123, while printing was
not invented until 1437. Since wood-engraving has been
practised there has been but little improvement in the tools
employed ; and if the engravings on wood are more beautiful
than they were some years since, it is due to the superior skill
of the engraver. The mode usually employed of pre-
paring a block for engraving is, to whiten the surface
with a mixture of flake- white and weak gum-water, either
with or without the addition of a little finely-pulverised
bath-brick ; this is usually applied with the finger, and is
rubbed off when dry. The object of this preparation is to
give a surface which shall render the lines drawn by the de-
signer distinctly visible to the engraver, whose duty is to en-
grave the block according to the design given. It is clear,
therefore, that it is of the utmost importance for the design
to be perfect, inasmuch as the beauty of the engraving
depends chiefly on this being the case ; hence the necessity
for paying a high price for good designs. To give some idea
of the cost of these, we may mention that as much
as £6,000 have been paid by an eminent publishing firm
for the wood-cuts which illustrate two volumes of a highly
popular woiiL now being issued by them.

Since the discovery of photography, frequent ■ attempts
have been made to take photographs on wood-blocks, but, we
believe, with little success. The various operations it was
thought necessary that the block should undergo before the
photograph was finished ready for the engraver, occasioned
the partial disorgamsation of the fibres of the wood, which
was thus rendered soft and unfit for the purpose. Various
attempts have been made from time to time to overcome this
difficulty ; and among the most recent attempts to print a
photograp)i on wood is that of Mr. Newton, who patented
his process at the commencement of this year. We have not
a copy of his specification at hand, but as far as our memory
Berves us, his process was as follows: — He took a limpid



varnish and with it saturated the pores of the wood ; this
varnish was composed of a mixture of asphaltum, ether, and
lamp-black, which was rubbed into the surface of the block
with a piece of leather until, as we have already said, the
pores of the wood were saturated. Collodion was then
poured on in the same manner as on the glass plate, and
sensitised in the silver bath, which was somewhat stronger
than is usually employed for sensitising glass plates, and
then exposed in the camera. It was afterwards developed
with a solution composed of sulphate of iron, acetic acid,
alcohol and water, and fixed in a solution of cyanide of
potassium, and washed.

In previous processea of this description it was the custom
to coat the surfac3 of the block with varnish, in order to
prepare it for the reception of the collodion film, which was
transferred from a glass plate to the varnished surface. As
may readily bo imagined, the thickness of the united films,
apart from any other reasons, must have seriously interfered
with the operations of the engraver ; and it appears to us
that in this respsct Mr. Newton's process could only mitigate
the evil; and consequently, as far as we are aware, the
process has not been very extensively adopted.

We now proceed to detail the result of our experiments,
and we believe it will be found in practice that our process
is free from those drawbacks we have indicated. We take
a suitable block and cover it, in the darkened laboratory or
by candlelight, with a mixture composed of oxalate of silver
and water, to which may be added a little gum or pulverised
bath brick, to suit the convenience of the engraver. The
mode in which the oxalate is spread over the sur£Eu;e is
precisely the same as that we have mentioned as being
employed by wool-engravers in applying the mixture of
flake-white and gum- water. A little of the substance, that is
to say, about as much as would lie on a fourpenny piece, for
a block four inches square, is sprinkled on the surfcice, and,
the finger being then dipped in water (either with or without
the addition of a little gum), the mixture is spread evenly
over the whole surface of the block by rubbing the finger
backwards and forwards across the block in various directions,
until the evaporation or absorption of the water leaves the
surfiace impregnated with a delicate and almost impalpable
coating of oxalate of silver. The block may be then placed
in a drawer, or any other place from whence daylight is
excluded, and there left till dry, or for any length of time
until required, as we have detected no deterioration or loss
of sensitiveness, even in blocks which had been prepared
six months ago, so long as they remained protected horn the
light. Oxalate of silver is susceptible of being acted upon
by the actinic rays, and when the block has been prepared
in the manner above indicated, it is only necessary to expose
it under a negative in the printing frame to sunlight,
and a positive picture is obtained in the same manner as on
paper prepared in the ordinary way. The block requires no

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THE PHOTOGRAPHIC NEWa



[DkC 31, 1858.



subsequent washing, nor any preparation of any description,
before being placed in the hands of the engraver ; so that he
receiyes it in precisely the same condition, as regards the
surface to be operated upon, asunder ordinary circumstances.
The engraver, however, must not expose the block to the
direct action of the solar rays while working at it, or it will
gradually blacken on the surface ; exposure to diffused day-
light, however, has no deleterious effect on it, unless it
be continued for a great length of time — say several hours.

We have before us, at this moment, a block on which a
portrait was printed by exposure under a negative in the
printing frame a fortnight ago ; and, although it has been
repeatedly examined and exposed to daylight, the portrait S
as distinct, in every respect, as though it were printed on
paper ; and all that is required to keep it so is to preserve
it from prolonged exposure to the light, which can be easily
accomplished anywhere, it being only necessary to turn it
face downwards on the table.

The advantages which may be derived from the adoption
of our discovery are numerous. Among them may be enu-
merated the cheap and rapid transference of pictures of all
kinds to the wood-block ; and this rapidity is not one of the
least of its advantages : for example, in the case of the lUus-
trated London News, it must not unfrequentiy happen that
the same mail which brings the details of our operations in
China brings also sketches from its artist there of the scenes
of these operations. Now, everybody knows how rapidly the
interest in such matters dies away in our busy country, and
consequently how necessary it is that these sketches should
be given to the public with the least possible delay. Such
delay, however, must necessarily occur when these sketches
have to be copied on to the wood-block by a draughtsman
previous to the engraver commencing operations ; but if this
sketch be handed over to a photographer, he can, in the course
of a few minutes, take a pnotograpnic copy of the exact di-
mensions required, which, in a vcrvlittie time longer, can be
transferred to the block, and the block be in the h^ds of the
engraver. Besides the advantage of rapidity, the smaU cost
at which the drawing can be transferred to a block would ren-
der it easy to have two or more blocks, so that when the first
block showed signs of wear a second could be substituted
for it — a very important consideration when an immense
circulation is taken into account ; and this applies equally
to illustrated periodicals which have a very large circu-
lation—in some instance extending to hundreds of thou-
sands, require several duplicate blocks of the same subject to
be taken by the electro-type process, in order to obtain a
perfect impression, as apart from the question of time the wood
wotdd become irretrievably damaged. There is at present
little probability of metal plates superseding wood-blocks in
printing with type, and it i& therefore of great importance that
the drawings on these blocks should be made with the greatest
exactness, and this can only be adequately attained by means
of photography. It is not necessary that we should enume-
rate all the cases in which this extreme correctness is abso-
lutely essential to convey a correct idea of the object sought
to be represented, but we may mention the reproduction of
anatomical subjects, of enlarged microscopic objects, and,
generally, of all animals and vegetable specimens. We see
no reason either why it may not be applied to the reproduc-
tion of stereoscopic views, which would, indeed, bring the
stereoscope within the reach of the humblest classes. Of
course the beauty and correctness of these views would de-
pend, to a certain extent, on the skill of the engraver ; but
most engravers would succeed in producing a block which
would be sufficiently correct for the purpose. Again, with
respect to reduced photographic copies of maps or plans
required to be printed with type, the reduced copies can
be transferred to the block with the most perfect accuracy
as to scale. •



ON AN ACTION OF LIGHT HITHERTO
UNKNOWN.*

BY M. NliPCB DE ST. VICTOE.

I HAVB now to speak of another series of experiments, but
still of the same kind.

A sheet of Swedish paper sized with starch only, and
impregnated with a weak solution of soda, potaasa, or
cyanide of ^tasfdum, and insolated for about three hours,
gives with tincture of curcuma a yellow picture in the part
insolated, and red in the parts not acted upon by the light.
If the paper is heated, it carbonises very rapidly in the
insolatea part^ Swedish paper not iized with starch does
not produce the same effect.

A sheet of paper sized vrith starch, such as is sold in
conmierce, insolated for about three hours, causes the blue
tincture of turnsole to redden in the part insolated ; besides
this the size will be found to have been removed from the
paper, or at all eventa to have changed ita nature, inasmuch
as the water penetrates immediately through the insolated
parts.

The effect is still more sensible when the pap^ is impreg-
nated with soda, potassa, or iodide of potassium ; but a
paper sized with gdatine does not become unsized under the
mnuence of light, in the time in which a paper sized with
starch does.

Ozonometrical paper, composed of starch and iodine of
potassium, according to M. Clo6z colours under the influence
of light ; that depends on its degree of hydration, for if it
is thoroughly dry it does not colour, but it becomes Uueish
the instant it is plunged in acidulated water.

Ozonometrical paper composed of red turnsole and iodide
of potassium, slightly moistened and exposed to the action
of the light under a negative, and passed in water after
insolation, gives a blue picture in all the parts acted upon by
the light ; the parts not acted upon remaining red.

Under the influence of light, a paper impregnated with a
solution of nitrate of uranium, especially if it is neutral,
colours of a rosy gray tint more or less deep, according to
the degree of moisture it possesses. The pict^ire would have
been coloured a very intense slate gray if it hod been
impregnated with a solution prepared in the following
manner: take nitrate of uranium 10 per cent.; nitrate of
copper 5 per cent. ; and yellow oxide of uranium 2J per
cent., and heat to render the liquor entirely neutral.

K with this same compound a design is traced on paper,
and exposed quite moist to the solar rays, in a very short
time a colouring will be perceptible under the influence of
the light ; and what is extraordinary is, that this colouring
disappears in obscuritv, and reappears on being again ex-
posed to the light, and this may be repeated a great number
of times ; but eventually the colour entirely diwippears.

For the colouring to take place rapidly, it is necessary
that the jiaper shoudd be neitner too moist nor too dry, a
slight humidity is the most suitable. The colouring ensues
rather rapidly even in diffused light ; the longer the time of
exposure, the greater its intensity, and the longer the time
necessary for it to disappear in obscurity ; if the exposure
has been too long, the paper will always preserve a greenish-
yellow tint.

A sheet of paper sized with starch, such as is sold in com-
merce, insolated under a glass negative, and passed in darkness
in a somewhat concentrated solution of iodide of potassium,
gives a red-brown picture, which becomes blue directiy it is
plunged in water ; this reaction renders evident the weakest
actions of the light on the starched paper.

A sheet of paper of commerce, sized with starch, exposed
to the action of the light for about three hours, with
half of its surface protected by a screen, and then after in-
solation plunged into a dish containing an alkaline solution of
indigo, and left there for a few minutes, and afterwards passed
in water, will, under the influence of the oxygen of the
atmosphere, become of a blue colour in the part insoJated,

* Cootinaed tmn pc8« IM.



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DftC. 31, I8M.3



THE PHOTOGRAPHIC NEWS.



195



while the part not insolated remains white. In the case of a
similar alieet of paper, treated in the same manner, and
plunged in a solution of sulphate of indigo, it is the insolated
part which becomes white, and that which has not been
acted upon by the light remains blue; the colouring be-
comes much more sensible if the paper is dried bj heat and
paased in a hot bath.

Logwood gives a red colouring to the insolated parts. The
sheet of paper, treated in the same manner, gives no ap-
preciable results.

It would be of importance to repeat these experiments,
not only in the luminous vacuum, but also in the dififerent
gases ; unfortunately it has not been possiWe for me to do
this.

I have now to speak of stuff impregnated with salts of
uranium.

If two pieces of cotton tissue be impregnated with a solu-
tion at 20 per cent., and then exposed to the sun, the one
wet and the other dry, and half of each piece protected by
a screen, it will be seen after an hour's insolation that the
prt acted upon by the light is ^preatly altered, but principally
m the wet stuff. If th£ portion be kept in darkness and
freely exposed to the air, the alteration will be seen to con-
tinue, and augment from day to day as long as the acquired
activity endures, ending by its being completely carbonised,
and assuming a very deep brown tint ; the parts protected
from the contact of the fight by the screen preserve their
tenacity.

The colouring which stufb impregnated with salts of
uranium assume under the influence of light is always
stronger when these stuf& are wet than when they are diy,
and it is the same with the alteration ; the less acid the
solution of nitrate . of uranium, the more the stuff colours,
and the reverse is the case when the acidity is augmented :
but the alteration is always in relation to the degree of



Online LibraryThomas Cradock Hepworth Sir William CrookesThe Photographic news for amateur photographers ..., Volume 1 → online text (page 60 of 99)