INVETION FIELD

The present invention relates to a digital photographic enlarger.

PRIOR ART

As is known, a photographic enlarger is a type of projector used for printing by projection of photosensitive material applied to a support.

It consists of a light source (usually incandescent) that is condensed or diffused through a translucent support and that by hitting a lens reprojects the image on a plane.

By deleting the negative holder section and replacing it with a phone or tablet depending on the optic installed, you can project a digital negative displayed on the screen and projected in a small medium format.

Due to the pyramidal scattering effect of a beam of light passing through an optic, in this case a much larger source of illumination than the backlight of mobile devices will be needed to carry the information and print a large photosensitive medium.

A digital version of the photographic enlarger is then created that replaces the film with an LCD panel allowing colour and black and white printing on the same machine. The LCD panel in question connects to a hardware input that manages its controls.

Similar to the analogue variant, the digital variant also has a number of disadvantages.

First, the vertical projection on the plane, the quantity and quality of the light and the use of standard optics limit the size and format that can be projected, making it difficult to expose photosensitive emulsions on non-classical media of sizes and formats other than photographic ones. Secondly, LCD panels have a limited color range and resolutions and use software corrections to create an optimized negative that only enhance color and contrast and the more you move towards a medium-large-format optic, the more the pixels that make up the LCD panel are visible.

In addition, the static nature of the panel itself limits the possibility of movement of the image inside it.

Finally, the light source is fixed and not directly modifiable, it cannot produce UV radiation for the impression of alternative processes (e.g. cyanotype) and also by replacing the source with a UV source, the projection optics and the LCD panel filter those same frequencies until they project too few for them to react with the photosensitive compounds.

OBJECTS OF THE INVENTION

The object of the present invention is therefore to solve the said problems of the prior art by providing a machine that guarantees optimal optical alignment and complete control over the modification of the plate and the light that strikes it, guaranteeing maximum freedom on sensitive size and format.

A further object of the invention is to provide a machine that projects a digital image without limits of relationships between the size of the negative and the optics used for the projection (a 6x9 digital plate can impress a 12x18 cm sheet, as well as a 91 .5x72 cm sheet with the same optics).

A further object of the invention is to eliminate the photographic format constraint for chemically developed projection printing.

Another object of the invention is to provide a machine that always allows to control the negative, its size and the occlusion of unnecessary blacks with respect to the size of the negative in proportion to the plate.

Last but not least, the aim of the invention is to provide a machine with versatile and interchangeable optical assemblies but at the same time compatible with all classic projection optics (small/medium/large format). Finally, the invention aims to integrate the artistic need to be able to interact with all the phases of the process and the possibility of impressing unconventional supports without limits in size and measurements with the commercial possibility of including the machine in an automated chemical printing process that, combined with the development of new papers and optimized chemical processes, allows also series production (think of artist books printed completely in photographic quality without the waste of expensive papers or pigments unnecessary for the texts and with derisory start-up costs of the machine).

Other objects and advantages of the invention will become apparent from the following description.

BRIEF SUMMARY OF THE INVENTION

The described purposes are obtained by means of a digital photographic enlarger, comprising a chassis having a longitudinally developing and housing an adjustable illumination group, configured to illuminate a digital plate an optical or a modular bioptic group downstream of the said digital plate, and wherein said chassis culminates in a semi-mobile mirror, with an adjustable ring dial for image direction, said digital photographic enlarger further comprising a heat dissipation system, and being characterized by the fact that said digital plate can be controlled by an external driver to assume different curvatures according to the inputs received from said enlarger.

The invention has numerous and important advantages.

First, the enlarger of the invention configures a machine that develops vertically to ensure optimal optical alignment, but with a horizontal final projection beam to have complete control over the modification of the plate and the light that hits it, guaranteeing maximum freedom on sensitive size and format.

In addition, the invention provides the implementation of a complete and functional digital plate.

The invention also allows a projection at variable distances from small format beyond the large format of the same image thanks to the possibility of modifying via software, the size of the image on the plate and the introduction of optical assemblies with variable planes.

In particular, the optical assemblies are engaged on a plane free to move on the axis of focus to determine the size of the image, the specific focus is controlled by a focus ring for microcorrections.

Advantageously, the invention also allows a Plug and Play type connection, which allows printing an image by connecting the machine to the telephone input to project the screen or implement the system with output apparatuses for viewing and editing the image software.

The invention also offers the possibility of impressing any type of support to which a photosensitive emulsion or film is applicable, as well as the possibility of modifying the quality and quantity of light in addition to the wavelength also to impress by projection, methods that were previously only possible with contact printing.

The invention also allows infinite focus projection.

It allows the projection on a photosensitive support of any file that can be processed by a machine: as mentioned, the system is of the Plug and Play type and works as a second monitor that reproduces exactly what is displayed by the device with which the enlarger dialogues.

The enlarger of the invention has no limitations regarding the proportion between the size of the negative and the image projected into focus thanks to the main optical system which, in addition to the focus ring for microcorrections, is engaged in the centre of a movable plane which, by moving on the projection axis, adjusts the overall size of the image.

The projection develops vertically because the mirror placed on top of the machine in addition to being adjustable to correct a possible Keystone effect given more by the projection environment than by the machine is mounted on a movable ring that allows to rotate the projected beam at will, in addition to allowing negative projection printing for methods that already use it (silver salts) makes it possible for methods that were previously only linked to UV contact printing (cyanotypes) by inserting a Wood glass between the LED and the first enlarger or replacing the LED with an exclusively UV one.

Further characteristics of the invention can be deduced from the dependent claims.

BRIEF DESCRIPTION OF THE FIGURES

The advantages of the invention are evident from an examination of the figures illustrated in the attached tables, where: figure 1 is a schematic view of the digital photographic enlarger, according to an embodiment of the present invention; figure 2a is a schematic view of a first illumination group variant applicable to the digital photographic enlarger of figure 1 ;

Figure 2b is a schematic view of a second variant of a illumination group applicable to the digital photographic enlarger of figure 1 ; figure 3 is a schematic view of a digital plate applicable to the digital photographic enlarger of figure 1 ; figure 4 is a top view of the digital plate of figure 3; figures 5a-5c are side schematic views of the digital plate of figure 3 in three different operating configurations; figure 6 is a side view of a first variant of an optical assembly applicable to the digital photographic enlarger of figure 1 ; figure 7 is a view of a second variant of an optical assembly applicable to the digital photographic enlarger of figure 1 ; figure 8 is a view of a third variant of an optical assembly applicable to the digital photographic enlarger of figure 1 ; figure 9 is a view of a bioptic group applicable to the digital photographic enlarger of figure 1 ; figure 10 is a top view of a variable plane for managing the optical assembly applicable to the digital photographic enlarger of figure 1 ; and figure 11 is a side view of the variable plane of figure 10.

DETAILED DESCRIPTION OF THE INVENTION

With reference to Figure 1 , a digital photographic enlarger is represented, according to an embodiment of the present invention, globally indicated with the numerical reference 10.

The main function of this machine (or enlarger 10) is the reproduction of a video input processed by an external driver and displayed by means of a digital plate 40 and projected through an optical group 30, so that each parameter is adjustable both manually and automatically for the optimal impression of a photosensitive emulsion applied on a medium.

The enlarger 10 comprises a chassis 12 (or containment body) that houses an adjustable illuminating group 14, a digital plate 40 and an optical or a modular bioptic group 30, wherein the chassis 12 culminates in a semi-mobile mirror 20, with an adjustable ring dial for image direction.

According to an embodiment of the invention, the digital plate 40 can be controlled by an external driver 90 to assume different curvatures as a function of the inputs.

The enlarger 10 also includes a heat dissipation system and on the main body there are two drawers for the insertion of filters and masks, one of which also allows the safe observation of the plate, and the front panel is removable to replace the modular optical groups as necessary

Complete the drawing of the enlarger 10, a further micro-drawer that placed at the height of the LED 80 allows the insertion of special filters for the shielding of the light radiation.

The most suitable building material is metal (at least for the illumination section), both for its dissipation properties and for those of light refraction, without excluding polymers or other materials.

The machine uses an electrical input to supply power to the illumination group 14 and the cooling system, while the digital plate 40 is independent and uses the connections of the driver 90 to receive a video signal and the current for its own power supply.

With regard to the illumination group 14, the following is observed.

The illumination is provided by an LED 80 mounted on a double capacitor (indicated by numerical references 81 and 82) with a diffuser 83 placed between the LED 80 and the first capacitor 81 to eliminate the dot pattern of the LED 80 itself and homogenize the light (figures 2a and 2b).

The led 80 used has characteristics such as the dimmability of the color temperature and the wave frequency of the light emitted that guarantee full control over the quality and quantity of light that affects the plate.

The power of the LED 80 is between 100 W and 500 W and can operate at 220 V or with a transformer from 220 V to 32-36 V, the current entering the system passes through a driver 90 that provides it to the illumination group and to the heat dissipation system.

A layer of viscous liquid 84 may be placed between the two capacitors to further increase the light refraction (see Figure 2b).

The light amplified by the system then passes through a Fresnel focalizer/lens 50 to parallelize the light rays before they strike the digital plate 40 (this step can be removed or replaced by a diffuser in association with certain lenses or chemical processes).

The heat dissipation generated by the led 80 is a fundamental part of the process and can occur:

- with a metal heat sink and two fans that force the air into and out of the chassis 12;

- with a liquid cooling system in which the radiator is internal and the fans for cooling the liquid are external to attenuate vibrations: - with a mechanical heat exchanger in which the heat extraction portion is in contact with a ceramic surface that electrically insulates the led 80 while the heat accumulation is mechanically and/or liquid dissipated.

In addition to temperature control by dissipation, it may be useful to apply a layer of heat-resistant glass between the plate 40 and the illumination group 14 to prevent excessive heat and ensure an optimal temperature for the operation of the plate.

The enlarger 10 is also equipped with filter drawers, LED light modifiers and a plate observation compartment.

The filter drawers are empty housings composed of a removable frame and are used to change the quality of the light beam after it has been struck by the plate, they can contain color filters or masks for changing the contrast and final rendering of the printed image (e.g. printing screens for grain effects).

In this system there are three compartments, two large ones suitable for different uses and one specific for light editing.

The filter drawer, located at the output end of the image, is the most suitable for modifying the final image and has a size greater than the extension diameter of the bioptic housing, so as to be able to modify the projected final effective yield.

The plate observation drawer, placed almost in contact with it, is more suitable for the application of masks and shields for printing effects.

In addition to allowing the observation of the same through the interlocking or magnetic reclining door, this ensures that the status of the plate 40, its position and the display of the input provided are always under control without causing eye problems as it is shielded. This drawer has a size that includes the maximum physical extension of the plate 40.

The micro-drawer placed above the LED 80 extends along the entire length of the LED 80 and keeps the light diffuser close to the first capacitor 81 .

It allows the insertion of diffuser filters to change the colour and intensity of the light (by printing in cyanotype, a Wood glass is inserted into this drawer to shield the visible light and increase ultraviolet radiation), making it possible to print by projection for contact methods.

Figure 3 is a schematic view of a digital plate 40 applicable to the digital photographic enlarger 10.

The digital plate 40 comprises an OLED or LCD IPS panel with SUPER PLS variant without backlight and with reduced filtering of UV radiation to which a polarizing layer 42 is applied on one side and an anti-heat glass 44 on the other.

The panel is connected to a driver via a 60-pin MIPI connector also without backlight input.

By providing power (numerical reference 92) and a video input (HDMI signal) (numerical reference 94) to the driver 90, it is possible to convert to data and display any image (data) on the plate 40.

The key feature of the panel is not the resolution or format but the DPI.

The density of pixels per point is exponentially more relevant than the size and resolution as it is directly responsible for the quality of the projection.

In a digital plate, the DPI takes the place of the analog grain present in the films, the more the value of the DPI is different, the more the grid will be detailed and invisible.

In other words, it is a sort of printing screen, a higher density with the same size will give a higher quality of the final image. Already at 515 DPI you get a clean, detailed print with a slight dotting in half tones.

The DPI directly and exponentially influences the quality of the image with respect to the resolution, the "photographic grain" of the film becomes the density of points of the plate allowing the optical magnification or reduction of the displayed image as well as the up/down-scaling software of the plate without great quality losses.

It is possible to communicate both portable and fixed systems with the 90 driver so as to allow a USB-C Plug and Play connection that can be associated with Android, iOS, windows, mac and linux devices to display on the plate an image that can be edited in real time with Photoshop or other dedicated software specially developed for the machine.

Figure 4 is a top view of the digital plate 40.

The digital plate 40 is inserted into a chassis 12 that ensures alignment with the structure and implements two pairs of slats (front connected in pairs) that can be extended or mechanically retracted to block the areas on the edge of the image after the final size of the file projected on the plate has been established to eliminate the filtering light from the excess pixels off in addition to limiting the angle of light expansion.

The characteristic flexibility of the panel combined with the motors to accompany the curvature make the plate flexible and allow to have a flat surface (figure 5a) or curve mechanically adjusted by means of motorized axes located at the ends of the panel in order to correct the focal arrangement of the projected light by means of some specific optics and increase the sharpness of the final image.

Ideally, the space between the panel and all the other components of the chassis 12 of the plate is equidistant and such as to allow both concave and convex curvature of the digital plate 40, as seen in figures 5b and 5c.

The video input hardware is connected in Plug and Play mode.

The advantage of a Plug and Play (LISB-C) connection in this system is the freedom of communication of the digital plate 40 with different systems.

The compatibility of portable devices such as phones, tablets or even PCs is possible for the display of the screen in pairing and consequent immediate management of the files but it is also possible the fixed implementation of inputoutput systems for the stand-alone management of the machine.

In the first case, a photo is taken from the phone, software creates the negative for printing and the displayed image is projected.

In the second case, I can connect a digital archive and manage the plate settings via peripherals or thanks to a touch panel integrated into the system and equipped with a processor with custom software. As for the software for managing the digital plate 40, it is noted that it makes it possible to resize and move the image freely in the available space, makes a huge number of files archivable and classifiable within it (especially in combination with a cloud) and makes it possible to modify and apply filters in real time.

It is possible to develop specific programmable software with executable command routines to automate everything that was previously done manually such as channel exposure for the management of dominant colour on dedicated papers or the application of masks timed at specific points and the multiple exposure of different images on the same support.

Incidentally, it is noted that the digital nature of the machine allows to create double exposures both starting from two digital images and processing them in posts (a definitive file is then projected), but also with a series of software commands with which it is possible to determine the exposure on the same medium of several images by timing them independently.

With regard to the optical assembly 30, it comprises a lens a plane-convex lens 32 (converging lens), a mirrored biconcave lens 34 (diverging lens) and a biconvex lens 36 in which the sides have different curvatures (converging lens) with a pinhole 38 at the end spaced variably from the lens (see Figure 6).

The diameter of the pinhole has a direct correlation with the focal length while the geometry of the hole, which must be perfectly circular, mainly affects the sharpness of the projection.

The thickness of the perforated material is also important, a ratio between the diameter of the pinhole and the thickness section of the non-optimized material can generate vignetting at the edges of the frame.

There is a formula, developed at the beginning of the twentieth century by Lord John William Strutt Rayleigh, for calculating the correct size of a pinhole which is as follows: d = 1.9 x rad (f x l)

Where: d = diameter of pinhole f = focal distance

I = average light wavelength.

Thanks to the characteristics of the machine it can be defined that:

The value of I for visible light is a portion of the electromagnetic spectrum between 400 and 700 nanometers (nm) that from a defined constant becomes an adjustable parameter thanks to the adjustable lighting source present in the machine.

The value of f in relation to the distance with the digital plate 40 can be modified by variations of the plane in space.

The value of f in relation to the distance between pinhole and lens can be changed by closing or bellows opening the side walls

The value of d is defined and understood around 1/100 of the average focal length at which the lens is intended to project and an integral part of the optical characteristics.

This optical group is the one that benefits the most from the possibility of curvature of the plate as it corrects the effect of vignetting at the edges of the image that is created due to the phenomenon of triangular dispersion of light most evident in this optic, characterized by an infinite projection.

Figure 7 is a view of a second variant of an optical assembly applicable to the digital photographic enlarger 10.

It is a fixed pinhole variant that can be made by inserting a double membrane 39 with parallel pinhole holes 38 inside the optic and defined with the same characteristics as the previous assembly, both in composition and in size.

The glass used for the realization of the optical elements (in addition to defined optical and mechanical characteristics) must be homogeneous and without defects, composed of quartz or silver glass to ensure a high transmission of all light frequencies (including UV and infrared). Figure 8 is a view of a third variant of an optical assembly applicable to the digital photographic enlarger 10.

In this case, using the same lens as the previous group, an adjustable diaphragm 37 is added inside the lens to manage the focal length to obtain a projection optical assembly.

Figure 9 is a view of a bioptic assembly applicable to the digital photographic enlarger 10.

Bioptic assemblies

Keeping an amplifying lens 35 fixed to magnify and adjust the image under the mirror it can be used an optical assembly of your choice

Classic optical assemblies

By taking advantage of the variable height of the surface it is possible to have a plane without optics with the size of the housing hole of the adjustable lens through a mechanism (or adapters) that makes compatible the use of any enlargement optics of any pre-existing format.

Figures 10 and 11 are respectively a top view and a side view of a variable plane for managing the optical assembly 30 applicable to the digital photographic enlarger 10.

Regardless of their characteristics, the optical assemblies 30 are engaged on a plane 110 that can vary its distance from the plate and integrates a ring system 120 for focal microcorrections.

The mobility of the plane 110 guarantees complete control over the distance between the optics and the plate for a free adjustment of the projectable magnitude and the focus regardless of the correlation between the image and focal magnitude of the lens.

A focus adjustment control mechanism 105 and a movement control mechanism on the focal axis 107 are provided. The planes fit into the system with a slide mechanism that guarantees complete modularity.

By inserting a two LED structure in which the first is used for focusing and setting the machine while the second LED is inserted above the first with a sliding system it is possible to connect the secondary light source to an electric capacitor to provide a single extremely strong light pulse capable of flashing the image on the photosensitive support.

By inserting a filter compartment between the capacitors and the light source, a Wood glass can be inserted to ensure more intense UV radiation.

By inserting the machine on a column and placing at the other end a (metal) surface with adjustable (magnetic) supports on which to project the image, there is a method to impress photosensitive supports in proportion to the depth of the column and linked to the size of the surface and by inserting the same in a darkening glass chamber in which there is an automatic machine for chemical development it is possible to automate the process (a mechanical system for moving and preparing the paper completes the automation).

By placing an L-joint at the height of the beam exiting the main mirror and inserting a variable angle mirror at the intersection, a projection on a vertical plane is obtained.

By miniaturizing the components, you get an adjustable high-resolution projectable screen that can be associated with an adjustable projection screen.

Android and Windows systems are by default compatible with the 90 driver. It is necessary to shield the output light from the device used with magenta filter.

Naturally, amendments or improvements may be made to the invention as described, dictated by contingent or particular reasons, without thereby departing from the scope of the invention claimed below.