GB2300728A

GB2300728A - Multi-purpose photographic easel

Info

Publication number: GB2300728A
Application number: GB9509298A
Authority: GB
Inventors: Lance Gregory Steward
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-05-06
Filing date: 1995-05-06
Publication date: 1996-11-13
Anticipated expiration: 2015-05-06
Also published as: GB9509298D0; GB2300728B

Abstract

A multi-purpose photographic easel has a base 1 pivotably supporting a lid 2 on pivots 5 having a central opening allowing one of a range of interchangeable printing masks 3 to be placed in register with sheets of light-sensitised material 4, one quarter of each sheet being exposed to light at any one time for test-printing, proofing and other rapid-printing operations, the optional guides being usable within the easel to provide for other sizes and formats than that designated for a particular example of the easel. The base 1 may have movable guides 10 to accurately position material 4 and mask 3 can be held in central opening by seal 9a. The base of the inverted easel provides an unobstructed enlarging support calibrated with magnification positioning of material within a frame comprising either the same sets of guides or sets of additional border forming blades.

Description

MULTI-PURPOSE PliOTOCRAPHIC EASEL This invention relates to a multi-purpose photographic easel used for all kinds of non-automated pilotograpllic test-printing, proofing and enlarging procedures as well as for copying flat artwork, photographs or documents by photographic means.

Various forms of test-printing devices are designed to expose parts of a sheet of photographic paper in succession, but these are not generally well-suited to the printing of the whole of an image in a single exposure and they therefore lead to unnecessary complications in assessing the information provided by the tests. Some devices are claimed to offer the facility for printing a variety of images onto a single sheet, with a system of removable masks of various shapes and sizes. A common feature of these devices is t the need to reposition the whole unit if the same image or part of an image is to be exposed repeatedly, which is both potentially inaccurate and slow.Certain types of multi-print easels attempt to address the paper-positioning problem by means of paper-carrying mechanisms operating within a fixed base or by means of adjustal,le bars or other stops, some requiring the paper to be removed , reversed and replaced between exposures.None of these devices provides any systematic relationship between test-prints or proofs and subsequent enlargements beyond their designated paper size either in terms of mechanical function or in terms of magnification and exposure determination, none of these provi(ies any useful control of print proportiolls or border widths, nor is any of them very well suited to accomodating a wide variety of paper formats in the way expected of a fully-functioning enlarging easel. The multi-purl)ose photorapje eael here here described and illustrated re]ates photographic sheet sizes, test-prints and enlargements in a systematic manner which integrates mechanical function with mat lo ema tics derived from fundamental optical principles.

According to the present invention there is provided a multi-purpose photographic easel consisting of a lighttight lid pivoted on a light-tight base forming an invertible unit whose internal dimensions relate to standard photographic sheet sizes such that the length and breadth of the internal working surface of the easel are one and a hal f times the dimensions of the designated photograpllic material, thereby allowing an interchangeable, lightshielding mask to form a calibrated aperture in the centre of the lid, the underside of this mask being in contact with the photographic material at the time of exposure so that all but one quarter of the sheet, or a similar proportion appropriate to a specific use, is shielded from light incident upon the easel, thereby allowing this quarter to be exposed, followed by the remaining portions of the sheet each in turn in the course of test-printing, of proofing, of the making of sets of identical prints and of any other photographic printing procedures in which it is desirable to produce up to four prints on a single sheet of light-sensitised paper, paper-substitute or film, there being no mechanism for papertransport other than the hand of the user, the complete easel being used in an inverted position to provide an unobstructed and mathematically-calibrated surface for enlarging, copying and other photographic operations.

In all of the descriptions contained herein it is understood that, unless there is a specific indication limiting their use, terms denoting various kinds of sheet material bearing an emulsion or emulsions having properties which render them capable of forming an image following exposure to light or other suitable sources of radiation if handled or processed in the appointed manner are freely interchangeable, the easel being equally intended for use with paper, papersubstitutes or sheet film.

Specific embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 shows, in perspective, the multi-purpose pllolouraphic easel in use for test-printing or proofing on one qriirler ol a sheet of pllotograpllic paper, the mask cover-plate 8 being i Iii; removed to allow a qu;;irtcr of t lie pa j) cr4 to I) p CX j) (). (' tl Figure 2 represents in a schematic form the relationship between the easel base 1, the printing mask 3 and a sheet of photographic paper 4 in one of its four optional positions, area 4a representing the part of the paper being exposed and area 4b representing those parts of the paper which have already been or are about to be exposed and which are at this point shielded from light by means of the lid 2 and mask 3; Figure 3 is a section of part of the easel indicating how the lid 2 forms a light-seal with the base 1 by means of an overlap 2a and by trapping a compressible seal 9 attached to the recurved lip la of the base 1, thereby preventing any light from reaching the masked parts of the paper 4 when the lid 2 is closed;; Figure 4 is a section of part of the easel showing how a compressible seal 9a forms a barrier when the printing mask 3 is attached to the lid 2 for all test-printing or proofing operations, the means of attachment previously indicated in Figure 1 being omitted here for simplicity. In this figure the paper 4 is shown being entirely shielded from light by means of the addition of the cover plate 8 also with a compressible light seal 9b, such as during intervals between tests requiring the enlarger or room light to be switched on;; Figure 5 is a section through the centre of t the easel showing the arrangement whereby small sheets of paper or film 4 are acc omod a ted within the easel, by means of accessory guides 10 cooperational with an alternative form of the printing mask 3 which is of reduced size thereby avoiding the possibility of fouling the accessory paper-guides 10 and thereby requiring the provision of an integral spacing plate 11 having a compressible seal 9a in contact with the lid 2, such an arrangement being suited to the production of passport photographs or to tlie testing of sheets of duplicating film; ; Figure 6 is a plan view of the inverted easel in use for enlarging onto a larger-than-designated sheet of paper which has been positioned within a frame consisting of the same paper guides 10 illustrated in Figure 5, the grid and scales marked on the easel base being omitted from this figure for-the sake of simplicity; Figure 7 is a plan view of the inverted easel in use i n use for the production of an enlargement with masked borders, using a set of additional masking blades 14, which could be any of those embodiments of this component of the invention represented in subsequent Figures. This figure also illustrates one of the means of supporting the easel at its correct working height, the means in this case being a set of magnetically-attached non-slip feet 12.The edge of the sheet being held in position and masked by the blades 14 is indicated by a dotted line; Figures 8a and 8b illustrate in section a simple form of magnetically-attached masking blade 14 supported on a strip of isotropic ferrite rubber magnet 15 which also serves to establish the position of the paper 4 on the inverted easel base 1, the two parts of the Figure showing how the blade is reversed to provide two separate border wIdths; Figure 9 shows the section of a magnetically-attached masking blade 14 of a more robust form capable of providing borders of four different widths by means of two isotropic ferrite rubber magnet strips 15 set into the blade proper 14, the whole blade assembly being both reversible and invertible.

The edges of the blade being relatively thick are hollowground 14a so that light incident on the blade at the usual angle of projection will not be reflected onto the edge of the paper 4. The Figure also shows that the accessory blade may be of substantial width while still allowing maximum use of the easel base to accomodate larger-than-designated sheets of photographic material; Figure 10 shows in section part of the base 1 of the easel in an alternative embodiment consisting of moulded plastic or cast alloy, with a non-magnetic paper guide-bar 21 having a peg, tongue or other protrusion 22 fitting tightly into a hole, slot or other depression in the easel base, this being a means both of format-reducing inside the easel and of positioning paper on the inverted easel base for making prints without borders;; Figure 11 shows in section a reversible and invertible masking blade 14 suitable for use on the inverted easel where this is in an embodiment made of plastic or alloy, the blade being held by means of staggered pegs, tongues or other protrusions 22 in any one of four positions with respect to the paper, thereby allowing the production of borders of up to four different widths; Figure 12 shows a section of a finely-adjustable magneticallyattached masking blade utilising a substantial isotropic ferrite rubber magnet 16 to establish the position of the photographic material 4 and to support, by means of a thumbscrew 17, the blade itself 14. The ferrite bar lies in a channel the edge of which is enclosed on one side only, so that the bar may lie in any position determined by the thumbscrew moving inside the slot 18.Being relatively oft, the ferrite magnet contains a metal or hard plastic threa(led insert 19 to accomodate the threads of the thumbscrew 17 in a durable arrangement. In order to prevent rinwanctl ligliL rrom reaching the masked border of the paper 4 an eccentricallyperforated circular plate 20 is squeezed between the ferrite bar 16 and the slot 18 in the blade 14.The Figure shows the blade forming a wide border on the right-hand edge of a photographic sheet 4, but it can be seen that other widths of border are created by altering the position of the blade relative to its magnetic support and/or by reversing the whole assembly with respect to the paper; Figure 13 shows part of the same adjustable masking blade, illustrating in plan view the underside of the blade 14 with its supporting ferrite bar and eccentrically-perforated plate, demonstrating the means by which this rotatable plate 20 prevents light from passing through the thumbscrew slot 18, hidden parts here being indicated by broken lines; and in which numbered component 5 is a pivot, component 6 is a screw or other suitable attachment and component 7 is a handle.

Referring to the drawings and to the above written descriptions, the easel is used for all test-printing and proofing purposes by first positioning and focusing the image on the surface of the easel base 1 typically so that either two opposite edges or all four edges of the projected image fall along the respective edges of the printing mask 3.

The enlarger or other light source is then extinguished so that a sheet of unexposed photographic material 4 may be positioned inside the easel by means of opening the lid 2 and guiding the paper with one hand until it aligns correctly with one corner of the easel base. The lid then being closed as shown in Figure 1, the first exposure can be made. For the second and subsequent exposures the lid is raised to a comfortable height so that the paper can be repositioned against each corner in turin, exposures being made in the required sequence. If the series of exposures is to be interrupted for any reason, or if it is desired to make any adjustments to the projected image between successive exposures, the cover plate 8 may be temporarily located within the body of the printing mask 3 as shown in Figure 4, thereby covering the aperture and providing a complete lightseal.Prints of any size and format up to a quarter of the paper size may be made by reducing the aperture of the mask 3 with black paper or adhesive tape orXby replacing the standard mask with one of the range provided for different formats, a suitable arrangement for the printing of passport photographs being represented in Figure 5. Where, for reasons of economy, convenience or presentation, it is desirable to reduce the sheet size a set of paper-guides provides a means of reducing the working area inside the easel, two of the four guides 10 also being shown in Figure 5. In most cases the guides 10 are positioned to retain the relationship of paper to working area and print size so that efficient use is made of the paper.In its preferred embodiment, being made of thin sheet steel, the easel is able to support paper-guitles which are no more complicated than standard industrial extrusions of isotropic ferrite rubber, these having good magnetic properties and a high coefficient of friction as well as being very inexpensive. These paper-guides are also used on the easel base when it is used to support photographs or documents for copying purposes, or for positioning sheets of paper when the easel is used for enlarging, the unit being inverted for any such purposes as shown in Figure 6.

Figure 2 illustrates, in a schematic form, the relationship of the internal working surface of the easel to the designated size of sheets of paper used within the easel, the relationship being determined by the ratio of the length of the sides of the paper to the dimensions of the working area. For example, an embodiment of the easel designated for paper sizes up to 10" x 8" (254mm x 203mm) has internal dimensions of 15" x 12" (381mm x 304.5 mm) so that the designated sheet may be displaced by one half of its length and breadth in order that one portion of it may be exposed at a time through an aperture in the printing mask 3 slightly less than one quarter the area of the sheet, the designated standard mask for this form of the easel measuring 125mm x 100mm to allow sufficient overlap of the paper edges as to hold it flat.In its preferred sheet steel embodiment or in an alternative moulded plastic form, it is possible for the registration of the print to be effected within a tolerance of less than one millimetre but for diagrammatic clarity the lines representing the edges of the paper 4c and 4d have, here as elsewhere in the Figures, been separated from those representing the mask 3, the base of the easel 1 and other components.

It follows from what has just been shown that since the base of the easel is substantially larger than the designated sheets it is also capable of supporting paper for enlarging up to, in this embodiment of the invention, the nominal 14" x 11" (356mm x 279mm) size. It is therefore possible to make four 125mm x 100mm test exposures on a standard 254mm x 203mm (10" x 8") sheet of paper and to use the exposure and filtration information gained from these in making an enlargement any size up to the nominal 14" x 11" (356mm x 279mm) using scales calibrated to provide exposure information based on the original 100mm wide test prints without further testing if the relative speed and filtration of the two paper batches are known.It is also convenient to be able to cut a sheet of the larger material down to the designated size for batchtesting prior to making any enlargements, it being most logical to always tise the standard l00mm-wide mask [or n 1 1 or p 1 s | r y I s liii s : o I i | ''ii y 1 iii ) Ii (' V v; I I I iii against o kllowll SUIIIOTd.

The aforementioned scales, being temporarily or permanently marked on the base of the easel are able to provide a direct reading of information relevant to the determination of exposure, either in terms of magnification ratios or exposure factors or giving actual exposure times adjusted to take into account the effects of lens extension, film format, paper reciprocity characteristics and user-specific factors such as enlarger construction as well as deviations from standard processing conditions. The scales provided with the easel are adjusted after conducting a series of tests which uses both sides of the easel, the inverted base being suitably marked with a 10mm grid as well as metric and Imperial scales and the standard mask being a fixed 125mm x 100mm.The use of the 125mm x 100mm test-printing mask as a standard has been decided because of the ease with which exposures are established within a convenient range of times and because of the ease and economy with which test exposures can be made at this size and related to all other printing conditions. It is noted that for printing from negatives or transparencies as large as or larger than the standard mask, an embodiment of the easel designated for paper nominally 16" x 12" (406mm x 305mm) having a mask 200mm x 150mm, or an easel designated for the nominal 20" x 16" (508mm x 406mm) sheets having a mask 250mm x 200mm may be more suitable, an arrangement similar to that shown in Figure 5 allowing these easels to accomodate modified versions of the standard mask still having apertures measuring 125mm x 100mm when it is desired to test-print smaller material.

The preferred embodiment of the easel in a form made of sheet steel has a base sufficiently thin for this to have no practical effect on exposure or focus when it is placed.

without its usual freely-removed supporting feet 12, on top of a larger conventional masking frame or directly on a much larger surface such as the enlarger baseboard, on a drop-table integral to a free-standing professional enlarger or on a wall used for mural projection. This is specified as the preferred option because of the practical implications of deman(lirlg professional applications where it is useful to be able to test-print on standard and economical 10" x 8" (254mm x 203mm) paper immediately prior to making enlargements bigger than a convenient 10" x 8"-designated model of the easel will allow.

The feet indicated in Figures 1,7 and 9 are preferably such that the plane of focus will lie equally on either surface of the easel base when the easel is turned over between operations so that no adjustment needs to be made to the image when aligning the easel on the optical centre of the enlarger in order to progress between test-prints and enlargements. This plane of focus normally lies at one inch (25.4mm) above the enlarger baseboard so that the automatic focusing and exposure systems integral to certain professional enlargers may be used efficiently and accurately without recalibration.

It is not necessary for those feet 13 shown in Figures 1 and 9 attached to the lid 2 to be removable in normal circumstances, but those 12 used to support the base 1 need to be either held in place by magnets such as the ferrite rubber strips used elsewhere in the easel, or simply placed freely where they are required beneath the easel when it is used for testing or proofing. Although represented in Figure 7 as square feet, the base supports arc olso very suj tnl,le i T I.licy ;Ire sirnlily blocks of foam slightly less than 25mm thick, of a similar width and as long is the easel is wide.

The means of accomodating sheets of paper on the base of the inverted easel are shown in Figures 6 to 13. The simplest means is the same set of four ferrite bars or strips 10 previously shown in Figure 5 in use for format-reducing in test-printing and proofing operations. These strips or bars are typically somewhat shorter than the relative sides of the easel so that they may easily form various frames inside it, but if they are only 2mm thick or less, their length may be increased so that they match the internal length and breadth of the easel, in this case being sufficiently flexible to be overlapped with respect to each other and easily inserted as required.Thicker bars need to have a relationsllip of their length to their width such that they may accomodate the smallest sheets to be used inside the easel while being sufficiently long as to provide ample guidance in positioning the paper by touch in total darkness. Bars seven and a half inches (about 190mm) and six inches (about 150mm) long hy one and one eigth of an inch (30mm is sufficiently close) wide are able to locate sheets in the standard and non-standard sizes from 5" x 4" (nominal, actually 127mm x 102mm) sheet film up to 8i2fl x 63" (216mm x 165mm) paper or film, it being very convenient that one or two sets of these bars will give the correct spacing for 81" x 6l" and 7" x 5" (178mm x 127mm) respectively simply by using the inside wall of the easel as a stop. Narrower bars, made for other industrial purposes and therefore less expensive, will work very well so long as they are carefully positioned, such as by means of spacing templates inserted between the bars and the easel walls and used without undue force being applied to the paper when it is located against the guides. These requirements in no way prevent the same bars of ferrite from being used to position paper for enlarging or flat material to be copied on the base when the easel is inverted. Various compromises with respect to size and performance are possible, such as that indicated in Figure 6.

The more sophisticated means of retaining sheets on the base of the the inverted easel shown in Figures 7,8,9,11,12 and 13 are all capable of producing masked borders. The arrangement for positioning them at less-than-maximum-capacity is shown in Figure 7. In normal use it is best to position two or three of the bladesrcorrectly, using the grid and paperpositioning markings on the base, before making the final adjustments to the image so that the paper position and final image area may be predetermined.The remaining blade or blades may be positioned after the paper has been guided under the edges of the first two or three blades, the edges of the paper itself providing a positive mechanical indication of the correct position. expending on the particular application and on the strength of tlie magnets employed, it may be desirable for one or two of the blades to have a nonmagnetic base or else a weaker magnet, too powerful a magnet making the positioning of the final blades once the paper is in place rather tricky. Applying the principle of positioning shown in Figure 7 allows the possibility of providing a system for masking borders on prints of any size whatever at relatively low cost as well as of providing borders of any width.This type of configuration is a natural consequence of the construction and uses of the easel, but may be equally employed beyond the confines of the easel itself such as on a custom-built steel support for floor or wall projection. The profiles illustrated in Figures 8,9 and 12 are easily adapted for specific applications where there are requirements for different widths of border, it being logical to provide wider blades with larger embodiments of the easel, the basic principle of each profile also being suited to cosmetic modifications which do not detract from usefulness or performance. An essential feature of all systems of blades is that they be able to provide cleanlymasked, square borders, this being achieved by precise shaping of the edges and of the ends of the blades.It is not at all necessary for the magnetic support;60tio be continuous along the full length of each blade provided that they are sufficiently effective in maintaining themselves and the blades in precisely the correct position on the easel base during normal, careful use and provided that they enable the edge of the paper to be easily and accurately located, it being evident from this that discs or short blocks of magnetic material such as ferrite or iron may be used in place of the strips and bars indicated in the drawings, this alternative construction being of particular value in reducing the weight of systems such as that shown in Figures 12 and 13 such as when these are to be used on large forms of the easel or on separate steel plates in a vertical position.Powerful ceramic magnets offer further increases in the performance:weight ratio, so that a highly-developed form of a blade adopting the principles and construction represented in Figures 12 and 13 may be at once light, precise and versatile, such as if the blade proper is machined in carbon-fibre. It is not intended that any of these blade systems be regularly use(l for h-igh-volume printing applications ,either the simple paper-guides providing a much quicker means of locating paper for enlargement purposes on the ase o the easel or o r the easel being used to print four images per sheet in its proofing mode of operation.The masking blades being intended strictly as an optional addition to the easel, the standard test-printing/proofing functions of the easel combined with its facility of use when placed on top of another, larger, conventional masking frame enable the user to work in a way which is both very flexible and extremely fast.

Embodiments of the easel moulded from plastic have been indicated in Figures 10 and 11. At the expense of some flexibility with regard to paper formats, guidestsslsuch as that shown in Figure 10 and masking blades'Gas complex as the one represented in Figure 11 can be positioned in a series of locating depressions, holes or slots in the manner indIcated.

Similar considerations of size as those governing the provision of magnetic guides and blades apply but, especially with regard to the type of blade shown in Figure 11, there must also be a relationship between the thickness of any locating pin, peg or tongue and the forces likely to act upon it. In the Figure the blade appears in a schematic form witll certain features exagerrated for clarity, the blade in reality being perfectly adequate for use on a standard-sized embodiment of the easel if it is about three millimetres thick with locating protrusions of a similar thickness or diameter, in such a form being comfortably able to provide borders of Smm, l0mm, 15mm and 20mm wide, or their Imperial counterparts l , 2 , 4" and 1".In order for this type of blade to function, it requires that the widest and narrowest borders be made by one side of the blade if the intervals separating the four borders are to be constant.

Figures 10 and 11 further demonstrate that embodiments of the easel other than those made from steel need to be sufficiently thick to provide a firm seating for the protrusions used to locate any systems of paper-guides and masking blades used.

Without needing further detail, it is evident that a fullyadjustable blade very similar to that shown in Figures 12 and 13 could easily be made from moulded and extruded plastic components simply by substituting a locating peg for te magnet employed in the preferred embodiment, cast and extruded alloy offering further manufacturing options without in any way changing the nature of the invention as a whole or of its component parts other than in the rejection of magnets as the principle means of holding accessories on the easel base.

The inter-relationships of the various functions, dimensions, proportions and components here described in detail are taken as fundamental to the invention, any significant departure from these inter-relationships being likely to diminish the effectiveness of the easel compared with that of the embodiments described and illustrated herein.

An alternative embodiment of the easel has been considered which embodies most of the principle features of the general form of the easel already described and illustrated, therefore requiring no illustration. In this alternative form the lid 2 is removable so that the inside of the easel base may be used for enlarging single images on sheets of paper of any size up to the maximum which the necessary insertion of these sheets will permit within a given version of this alternative embodiment, this size being governed primarily by the space which is not obstructed by the recurved lip la of the easel base.Versions of this embodiment which sacrifice the easel's inherently light-safe qualities would allow enlargements up to the full size of the inside of the easel base, which would be, in the case of the standard 10" x 8" (254mm x 203mm)designated version of this alternative embodiment of the easel, 15" x 12" (381mm x 304.5mm), by means of being constructed without the efficient light-barrier illustrated in Figure 3, or else a version could be created with the same paper capacity having an alternative light-trap consisting of standard devices such as a velvet seal which would be situated between adjacent vertical walls of the lid and base, or such as a groove in the rim of the base into which the lid naturally falls when it is closed.The particular advantages of any such non-invertible embodiments of the multi-purpose photographic easel would lie on the one hand in the possibilities of mass-production of a version having limited border-masking capabilities and on the other in versions of the easel which allow substitution of the standard test-printing lid by a lid containing a glass plate for contact-printing, by a series of fixed-format masking frames pivoted similarly to the standard lid for the rapid production of series of enlargements or by a fully-adjustable two, three or four-bladed masking frame of a conventional kind but operating inside the tray formed by the easel base.

The technology of these other means of printing being common knowledge, they need no further description here and any such replacement lids, frames or plates can merely be considered convenient accessories which may enhance the usefulness of any such alternative embodiment of the multi-purpose photographic easel.

Claims

1. A multi-purpose photographic easel consisting of a light tight lid pivoted on a light-tight base forming an invertible unit whose internal dimensions relate to standard photographic sheet sizes such that the length and breadth of the internal working surface of the easel are one and a half times the dimensions of the designated photographic material, thereby allowing an interchangeable, light-shielding mask to form a calibrated aperture in the centre of the lid, the under side of this mask being in contact with the photographic material at the time of exposure so that all but one quarter of the sheet, or a similar proportion appropriate to a specific use, is shielded from light incident upon the easel, thereby allowing this quarter to be exposed, followed by the remaining portions of the sheet each in turn, in the course of test-printing, of proofing, of the making of sets of identical prints and of any other photographic printing procedures in which it is desirable to produce up to four prints on a single sheet of light sensitised paper, paper-substitute or film, there being no mechanism for paper-transport other than the hand of the user, the complete easel being used in an inverted position to provide an unobstructed and mathematically calibrated surface for enlarging, copying and other photographic operations.

2. A multi-ptlrpose photographic easel as claimed in Claim 1 wherein the use of an additional cover plate tempor arily located on the printing mask completes a total light-seal thereby permitting certain test-printing antl multiple print-making procedures requiring images to be projected onto an area closely approximating that part of the material upon which it is intended to print as well as permitting sensitised material to be safely retained within the easel in normal room light or in full sunshine, during interruptions to tlle printing session or for specialised printing techniques involving powerful light sources such as the sun.

3. A multi-purpose easel as claimed in the preceding Claims having the underside of the base marked with a grid to facilitate the positioning of sheet materials, which grid is co-operational with certain scales temporarily or permanently marked on the said base, these scales being calibrated in relation to the masks employed for testing in such a way that magnification and exposure information can be read directly thereby facilitating the rapid and accurate transfer of information obtained from test prints made inside the easel to subsequent enlargements made on the inverted base without t need for retesting, both the grid and such scales being centrc(l on thc optical axis therelly perrniLLii enlargement with minimal adjustment to the position of the easel, certain of the same scales also offering an aid to the determination of magnification and exposure in photographic copying applications when the same easel is used on a copying stand, no modifications needing to be made for any of these purposes.

4. A multi-purpose easel as claimed in any preceding Claim wherein a set or sets of movable paper-guides is able to accomodate smaller photographic sheets than those for which a specific embodiment of the easel is designated, these guides being co-operational with appropriately smaller masks or with temporary modifications of the standard designated mask and having the additional purpose of forming a freely-adjustable frame on the base of the inverted easel when it is used for positioning sheet materials for the making of enlargements or when it is used to support flat documents to be copied photographically.

5. A multi-purpose photographic easel as claimed in Claim 4 wherein the means of attachment of the movable guides is magnetic and wherein the easel is wholly or partly constructed of steel so that the guides may be located anywhere appropriate to their use on the easel.

6. A multi-purpose photographic easel as claimed in Claims 1 to 4 wherein the easel is produced in a form which does not readily support magnetic components but wherein a series of slots, holes or other depressions allows for the provision of movable guides within pre-set configurations such as those relating to the most commonly-used sheet paper sizes, embodiments of such a form of the easel typically being made of moulded plastic or cast alloy.

7. A multi-purpose photographic easel as claimed in Claims 1 to 5 having an additional system of independently usable masking-blades normally used on the base of the inverted easel for the production of prints with blank borders, the blades being of a construction which employs magnets both to establish the position of the photo graphic sheet and to support blades proper capable of producing borders of fixed or variable widths.

8. A multi-purpose photographic easel as claimed in Claim 6 wherein magnets cannot be effectively used but wherein additional masking blades capable of producing borders of fixed or variable widths are retained on the base of the inverted easel by means of slots, holes or other depressions.

9. A multi-purpose photographic easel as claime(l in any previous Claims wherein the unit is supported in such a way as to maintain the plane of focus at the industry-standard one inch (25.4mm) above the enlarger baseboard, whether the easel is being used in its test printing and proofing position or inverted for enlarg ing, in order to make full use of the automatic focusing and exposure capabilities of certain professional enlargers as well as to avoid the need to refocus when moving from one type of printing operation to another, the necessary supports being provided by feet attached to the lid and by feet or supporting blocks which may, in the case of forms of the easel made from steel, or may not include magnets or which may or may not incorporate simple mechanical attachments in the case of forms of the easel made from non-ferrous material.

10. A multi-purpose photographic easel as claimed in Claim 9 and in any previous Claims, wherein the thickness of the base is sufficiently small as to have no serious effect on focus and exposure, such that the easel may be conveniently used for test-printing and proofing purposes without its base-supporting feet such as when placed on top of larger conventional masking-frames or other supports upon which it is desirable to make enlargements beyond the capacity of the particular embodiment of the easel.

11. A multi-purpose photographic easel as claimed in previous claims excepting that the easel be not invertible, the lid being instead removable in order that enlargements may be made within the easel base using similar means of locating the sheets of photographic material to those claimed in previous Claims and in order that some versions of this alternative embodiment of the easel may have provision for a system of accessory interchangeable lids and frames used for further printing applications.

12. A multi-purpose photographic easel subs tan to ally as described herein with reference to Figures 1 to 13 of the accompanying drawings.

12. A multi-purpose photographic easel substantially as described herein with reference to Figures 1 to 13 of the accompanying drawings.

Amendments to the claims have been filed as follows 1; A multi-purpose photographic easel consisting of a light-proof lid pivoted on a light-tight base, forming an invertible unit whose internal dimensions relate to standard photographic sheet sizes such that the length and breadth of the internal working surface of the easel are one and a half times the dimensions of the designated photographic material, the construction of the easel's lid allowing an interchangeable, light-shielding mask to form an aperture in its centre, the underside of this mask being in contact with the photographic material at the time of exposure so that all but one quarter of the sheet, or a similar proportion appropriate to a specific use, is shielded from light incident upon the easel, thereby allowing this quarter to be exposed, followed by the remaining portions of the sheet each in turn, in the course of test-printing, of proofing, of the making of sets of identical prints and of any other photographic printing procedures in which it is desirable to produce up to four prints on a single sheet of lightsensitised paper, paper-substitute or film, there being no mechanism for paper-transport other than the hand of the user and no need for the location of the easel to be altered during the making of a set of prints, the complete easel also being capable of use in an inverted position to provide an unobstructed surface for making single prints, for copying and for other photographic operations.

2. A multi-purpose photographic easel as claimed in Claim 1 wherein the use of an additional cover-plate temporarily located on the printing mask completes a total light-seal thereby permitting certain test-printing and multiple print-making procedures requiring images to be projected onto an area closely approximating that part of the material upon which it is intended to print as well as permitting sensitised material to be safely retained within the easel in normal room light or in full sunshine, during interruptions to the printing session or for specialised printing techniques involving powerful light-sources such as the sun.

3. A multi-purpose photographic easel as claimed in the preceding Claims having the underside of the base marked with a grid to facilitate the positioning of sheet materials, which grid is cooperational with certain scales temporarily or permanently marked on the said base, these scales being calibrated in relation to the masks employed for testing in such a way that magnification and exposure information can be read directly thereby facilitating the rapid and accurate transfer of information obtained from test prints made i ri SI (I o L ho easel to subsequent enlargements made on the invertc(l base without the nead i0CC(I for detesting, bot the grid and such scales heing centred on t Ii e optical axis theby l)erlllitt illg enlargement with minimal adjustment to the position of the easel, certain of the same scales also offering at aid to the determination of magnification and exposure in photographic copying applications when the same easel is used on a copying stand, no modifications needing to be made for any of these purposes.

4. A multi-purpose easel as claimed in any preceding Claim wherein a set or sets of movable paper-guides is able to accomodate smaller photographic sheets than those for which a specific embodiment of the easel is designated these guides being co-operational with appropriately smaller masks or with temporary modifications of the standard designated mask and having the additional purpose of forming a freely-adjustable frame on tile base of the inverted easel when it is used for positioning sheet materials for the making of enlargements or when it is used to support flat documents to be copied photographically.

5. A multi-purpose photographic easel as claimed in Claim 4 wherein the means of attachment of the movable guides is magnetic and wherein the easel is wholly or partly constructed of steel so that the guides may be located anywhere appropriate to their use on the weasel.

6. A multi-purpose photographic easel as claimed in Claims 1 to 4 wherein the easel is produced in a form which does not readily support magnetic components but wherein a serious of slots, holes or other depressions allows for the provision of movable guides within pre-set configurations such as those relating to the most commonly-used sheet paper sizes, embodiments of such a form of the easel typically being made of moulded plastic or cast alloy.

9. A multi-purpose photographic easel as claimed in any previous Claims wherein the unit is supportecl in srich a way as to maintain the plane of locus at tulle industry-stanclard one inch (25.4mm) above tlle erilirger baseboarcl, whether the easel is being used is its test- printing and proofing position or inverted for enlarg- ing, in order to make full use of the automatic focusing and exposure capabilities of certain professional enlargers as well as to avoid the need to refocus when moving from one type of printing operation to another, the necessary supports beillg provicle(l by feet attached to the lid and by feet or supporting blocks which may, in the case of forms of the easel mantle from steel, or may not include magnets or which may or may not incorporate simple mechanical attachments in the case of forms of the easel made from non-ferrous material.

11. A multi-purpose photographic easel as claimed in previous claims excepting that the easel be not invertible, the lid being instead removable in order that enlargements may be made within the easel base using similar means of locating the sheets of photograpllic material to those claimed in previous Claims and in order that some versions of this alternative embocliment of the easel may have provision for a system of accessory interchangeable lids and frames used for further printing applications.