US2493128A

US2493128A - Photograph negative etching tool

Info

Publication number: US2493128A
Application number: US595051A
Authority: US
Inventors: Fulkerson Volney Everett
Original assignee: Individual
Current assignee: Individual
Priority date: 1945-05-21
Filing date: 1945-05-21
Publication date: 1950-01-03
Anticipated expiration: 1967-01-03

Description

Jan. 3, 1950 v FULKERSON 2,493,128

PHOTOGRAPH NEGATIVE ETCHI'NG K'QOL Filed May 21, 1945 Vomev EVERETT FULK ERSON INVENTOR.

ATTORNEY Patented Jan. 3, 1956 UNITED STATES PATENT OFFICE PHOTOGRAPH NEGATIVE ETCHING TOOL v Volney Everett Fulkerson, Portland, Oreg.

Application May 21, 1945, Serial No. 595,051

3 Claims. 1

The present invention relates to photograph etching tools and more specifically to knives for use in refinishing of photograph negatives.

In the art of refinishing photograph negatives it is a common practice to reduce the density of certain portions by removing, such as by scraping with a sharp edged tool, thin layers from the silver deposit on the negative. The quality of the results depends not only upon the skill and workmanship of the operator but to a very large extent upon the design and balance of the etching knife. Such etching knives as have been provided here-- tofore are more or less clumsy and awkward to handle and of improper design making the work of photograph etching very tedious, tiresome, and difficult to perform.

It is an object of the present invention, therefore, to provide a new and improved photograph negative etching tool whereby the refinishing of photograph negatives is rendered easier than with tools heretofore available.

A still further object of the present invention is to provide a new and improved knife for use in etching photograph negatives by means of which thin layers of photographic deposit may be removed with ease and with a high degree of accuracy and requiring a lesser degree of skill than is required with photograph etching knives as have been heretofore provided.

In accordance with an illustrated embodiment the knife of the invention comprises a relatively lightweight holder having a metal blade securely mounted in the outer end thereof which blade is provided with a scraping edge on the outer end thereof so designed as to render the manipulation thereof relatively simple. The tool is so balanced that it more or less automatically assumes a proper position in the hand of the operator.

Additional features and advantages of the tool of the present invention will appear from the following description taken in connection with the accompanying drawing while the aspects of novelty will be pointed out with greater particularity in the appended claims.

Referring to the drawing, in Fig. 1 is shown a photograph negative etching knife, partly in section, constructed in accordance with one form of the present invention; Fig. 2 is a view similar to that of Fig. 1 but showing the tool rotated through 90; Fig. 3 is an enlarged fragmentary view of the blade unit incorporated in the tool and showing the forward face thereof; Fig. 4 is an enlarged fragmentary view showing the rear side of the blade; and Fig. 5 is a detailed view 2 illustrating a. cross-sectional view taken along the lines 55 of either Fig. 3 or Fig. 4.

The photo etching tool of the present invention is comprised essentially of a relatively lightweight holder In with a blade ll mounted in the end thereof and extending longitudinally therefrom. While the holder l0 may be of different materials it is preferred for reasons of economy and expediency of manufacture to form it of Wood and, as shown, it resembles closely a conventional pen holder. The holder It is provided with a cylindrical stem portion l2 of reduced diameter and which is surrounded by a sleeve [3 of a suitable semi-resilient material, such as cork, forming a finger grip.

The blade H consists of an elongated piece of relatively thick steel having a maximum width corresponding substantially to the diameter of the stem I2, the shank end M of the blade being fitted into a cooperating slot formed into the end of the stem l2 and rigidly secured therein as by cementing. In order to reinforce the stem 12 and particularly the slotted end portion receiving the blade shank a thin sleeve 15, preferably of metal, is fitted tightly over the stem l2 throughout the full length thereof and over which is mounted the finger grip sleeve l3.

The blade II is of a suitable high grade steel capable of taking and holding a sharply ground edge. The front surface of the blade H, as viewed in Figs. 2 and 3 is fiat throughout its full extent and in the normal usage of the device the plane of the blade face extends substantially perpendicularly to the work surface as will be described more fully hereinafter. The blade I I is provided with a cutting edge 20 at its outer end and which extends across the full width of the blade and at such an angle that as the tool is held in the hand during normal usage the edge 25 extends substantially parallel with the surface of the photograph negative being worked upon. As illustrated more clearly in the enlarged detailed view of Fig. 3 the blade is shown extending at an angle with respect to the horizontal of substantially it being understood, however, that this angle is not to be taken as being critical since it is susceptible of considerable variation and it is to be understood that this angle is merely representative of the normal angle at which a tool device of this sort is normally held. The edge 29 is formed by removal of metal, such as by grinding, solely from the reverse side of the blade as indicated at 22 in Figs. 1, 4 and 5. The edge 20 is furthermore provided with a slight curvature the 3 radius of the curvature being several times greater than the length of the edge such as roughly about the length of the blade portion projecting from the end of the holder. As will become apparent subsequently, this radius of curvature may be varied somewhat.

The outer end of the blade is preferably somewhat narrower than the width thereof in the shank, the reduction in widthbeing accomplished in this instance by removal of metal from'the lower side of the blade as indicated at 23. The center of the cutting edge 20 is thus shiftedda slight distance above the longitudinal axisaof the holder, in the position of normal usage, as indicated by the distance 25 betweeni'the longitudinal axis of the holder indicated by the center line 26 and the line 2? indicating the center lineextending through the center of the cuttingedge 20. This feature is of considerable importance in that With the tool leaning against. the hand in the normal angle of usage as shown in'FigJ B the center of gravity of the tool is below the 'line extending between thepoint of contact at .the outer end of the holder again'stIthe hand and the point of contactbetween the center of the cutting edge and the surface .of. the'filmli2l.

Thus without the'thumb and forefinger gripping against the opposite sides of the grip T3 the tool will inherently assume the proper working angle of perpendicularity of the forward face of the blade ll withrespect to the surface of the horizontal film 2|. 'It willbe obvious that in bearing down on the'tool for effecting scrapping operation upon' the surface of'the negative it is not necessary to counteract. any tendency of the tool to twist between the thumb and forefinger and which contributes materially 'to'the ease with which this tool'may be manipulateddoy the operator.

The upper edge of theblade His further- *morebevelled by removal of metal'from'the rear side thereof as indicated atf3fl the angle'ofbevel corresponding substantially to the'normal angle of vision over the upper edge of the blade, 'as

indicated by the line 3|, 'of 'the operator in "manipulating the tool in "front of him thereby materially diminishing the 'field ofbbstruction of vision upon the negative during. the etching -operation. As is well understood'by those skilled "in the art, in the etching of negatives the blade 'is drawn toward the operator Who'observesthe results of the scraping operation "by watching rigidity to the cutting edge .and further enabling it to be ground and honed.to provide a "sharp and durable edge.

In the normal usage'of the .tool it is so held in the hand that the cutting edge "2'fl'contacts with the surface of the "film substantially; at the center thereof. In the.scrapingoperationgreatest penctration into the emulsion layer 'of' the" negative is effected at'the center ofthe cutting edge and with uniformgradation outwardlyl'in both directions from the center thus. sharp. lines at the opposite edges of the shave are eliminated.

Should it be desired, however, to (shave .up. toe" fixed sharp line on the negative .thenLby. a very slight upward tilting of the holder, or. by tilting the negative by lifting it .from..-one..edge .with the left hand, .the .outer- .tip. endof. the .bladecan then be brought into contact with the negative and because of its needlepoint nature it can be manipulated with ease and accuracy to effect removal of the emulsion deposit on the negative to the predetermined line. On the other hand, no sharp line is formed on the opposite edge of the shave and which is smoothly graduated depending, of course, upon the angle of tilt.

Particular attention is also directed to the fact that the -forward face of the blade II is flat ethroughout its full extent and more particularly immediately adjacent the cutting edge so that the edge itself, or rather the point of contact -between the cutting edge and the surface of the 'film' is always in the line of vision of the oper- .zator-as indicated' by the dotted line 34 in Fig. 5. This is of very considerable importance because '"lnthe case of ordinary photo etching knives in whiohuthe edge is formed by grinding from both sides of the blade, the forward edge is bevelled .inwardlyand it is necessary. for the operator to .raise his head inorder to look over the rear side of the blade to observe closely the exact point of contact. of thecuttingedge with the work surface. This .is extremely tiresome. With the cutting edge provided by removal of metal solely from .the rear side of the blade as shown and with .the front surface maintained fiat the cutting edge is always in the line of vision of the oper- =ator when seated in a comfortably erect posture. Having described the principle of the invention in what is considered to be a preferred embodiment thereof it is desired that it be understood that .the various specific'details shown are merely .illustrative and that the invention may be car ried out by other means without departing from the true spirit and scope of the invention as defined inthe-following claims.

What. I claim is:

'1. --A:photographic negative etching tool comprising an elongate holder, an elongate fiat steel :blade secured in the end of said holder and pro- :jecting longitudinally therefrom,.said blade having a longitudinal faceside and a'rear side opposite saidface .side, the .face .side of said blade being parallel .with the longitudinal direction of saidholder and blade .and plane throughout the .full extent thereof, the rear side of said blade being beveled at the end thereof to definea single sharpscraping edge at the end of said face side, .saidqscraping edge'extending throughout the full width ofsaid :blade .at anangle of substantially 45xw'ith respect to the longitudinal axis of said 1-holder,.said scraping edge having a slightly conrvexwcurvaturev throughout the full extent thereof and extending on both sides of the longitudinal .:,axis of said holder.

2. A;.photographic'negative etching tool com- ,prising an:elongate'-holder, an elongate fiat steel -.-blade secured :in the end ofsaid holderand pro- =je'ctinglongitudinally therefrom, said blade havsingia-longitudinal face side anda rear sideopposite said face:.side,..said face aside of.said blade being parallel with the longitudinal direction of .:said holder andsaid blade and plane throughout the full extent thereof, the rear side of saidblade being bBVBl Edfifb the-end thereof vto'define a single .sharp.--scraping edge at the end of-said face side, e'saidscrapingedge extending throughout the full :width :of saidfacesideetan angle of about 45 ;.with respect *to the longitudinal axis of said holder, the side edge of said blade extending to .the tip end of saidscraping edge being longitu- .dinally beveled on said rear side, saidscraping edge having a slight convex curvature through- 5 out the full extent thereof and extending on both sides of the longitudinal axis of said holder.

3. A photograph negative etching tool comprising a holder, a flat steel blade secured in the end of said holder and projecting longitudinally therefrom, said blade having a face side and a rear side opposite said face side, said face side of said blade being fiat throughout the full extent thereof, said rear side of said blade being beveled at scraping edge being ofiset slightly with respect to the longitudinal axis of said holder in the direction of the tip of said scraping edge.

VOLNEY EVERETT FULKERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 303,308 Miller Aug. 12, 1884 678,643 Clarke July 16, 1901 900,374 Huss Oct. 6, 1908