WO2000008426A1

WO2000008426A1 - Empirically derived inking colour reference chart

Info

Publication number: WO2000008426A1
Application number: PCT/AU1999/000621
Authority: WO
Inventors: Kenneth Z. Detonssk
Original assignee: Detonssk Kenneth Z
Priority date: 1998-07-31
Filing date: 1999-07-30
Publication date: 2000-02-17

Abstract

A swatch book (10) is based on an inking standard which has been empirically derived from corresponding process colours of proofs, whereby the specified process colours of the inking standard accurately replicate the proofs. The swatch book has a series of leaves (1A, 1B) each dedicated to one of the process colours. The process colour and its tonal variants (4A, 5A, etc.) are shown as individual swatches. Metallic variant (6A) is presented adjacent to tonal variant (4A). A secondary process colour (7A) and its metallic variant are also presented.

Description

EMPIRICALLY DERIVED INKING COLOUR REFERENCE CHART

FIELD OF THE INVENTION

The present invention relates generally to an inking standard, and a process colour reference chart or target, and tuner.

BACKGROUND TO THE INVENTION

Prior to the computerisation of the graphic design industry, designers relied on graphics tradespeople to create plate ready film that was colour correct. Colours chosen by designers for process colour printing would be made up by hand. The graphic tradespeople would cut, register and place various dot density tint film on the separate process colour make-up film as the colour required. Existing colour swatch books have the origins when such swatch book's main objective was to facilitate communication in regards to this process between the designer, graphics tradespeople and printers. These swatch books are now used by computer based designers who no longer require this communication with graphics tradespeople. The computer based designer translates the colour information in the swatch book directly into the program they are using. Hence there is no make-up film as the digital art file is plotted direct to separated plate ready film or direct to plate. The communication vehicle between the designer and the printer is now predominantly the proof made from the plate-ready film. The means to gauge variations in the results shown on the proof and a specifiable inking standard to achieve a perfect proof match, has to date been non existent for the designer. The computer based designer has the potential to specify any quantity of process make-up colours of varying dot densities that were previously unavailable.

US patent No. 5,174,758 discloses a colour swatch book including a plurality of pages each having individual colour swatches. The colour swatches are depicted in the standard four process colours, namely cyan, magenta, yellow and black (CMYK), of varying half-tone dot densities. A single page includes a distinct hue together with a series of lighter tints of that distinct hue. In one example the lighter tints are reduced in each step by about 15% of the original dot density of the distinct hue.

The intention or objective of the swatch book of US 5,174,758 is to allow a printer to accurately reproduce four-colour process as selected by a designer. Swatch books of this type have been produced to reflect Standard

Web Offset Publishing (SWOP) inking standards which are designed for high volume/high speed roll-fed machines. However, SWOP is not indicative of the colour quality achievable from advancements made in sheet fed offset printing presses nor advancements made in ink pigmentation.

That is, SWOP or any other known inking standard does not accurately reflect the four process colour' s pigment hue as shown on a proof.

SUMMARY OF THE INVENTION

According to one aspect of the present invention there is provided an inking standard of specified process colours, the inking standard being empirically derived from corresponding process colours of proofs whereby the specified process colours of the inking standard accurately replicate the proofs.

According to another aspect of the present invention there is provided a method of process colour creation involving the steps of: selecting a process colour, having a specified makeup, together with tonal variants of that colour, the tonal variants each having a make-up which is mathematically related to the make-up of the process colour; and reproducing the process colour and at least one of its tonal variants based on the specified and mathematically related make-up of the process colour and its tonal variant, respectively, said reproduction being performed using an inking standard of specified process colours, said inking standard being empirically derived from corresponding process colours of proofs whereby the specified process colours of the inking standard accurately replicate the proofs.

Generally there are four (4) process colours namely cyan, magenta, yellow and black (CMYK) . Preferably the inking standard is an international scale inking standard consisting of inks of the correct pigmentation made by, but not exclusive to, Hostmann-Steinberg .

Typically, the method of process colour creation further involves a step of reproducing a metallic variant of the process colour (s) and/or the tonal variants wherein the metallic variant is produced by superimposing the process colour (s) and/or the tonal variants on a 5^th colour silver. More typically, this involves underprinting of the process colour (s) and/or the tonal variants on a separate press pass with the 5^th colour silver.

According to another aspect of the present invention there is provided a process colour selector chart comprising a plurality of leaves or pages each being dedicated to a process colour having a specified make-up, each of said leaves or pages including a series of tonal variants of the corresponding process colour, the tonal variants having a make-up which is mathematically related to that of the corresponding process colour whereby in operation a selected process colour and its tonal variant can be reproduced based on the specified and mathematically related make-ups of the process colour and its tonal variant, respectively, said reproduction being performed using an inking standard of specified process colours, said inking standard being empirically derived from corresponding process colours of proofs whereby the specified process colours of the inking standard accurately replicate the proofs.

Generally, the process colour selector chart is represented in the form of a swatch book having a series of leaves each dedicated to one of the process colours and its tonal variants shown as individual swatches. Alternatively, the selector chart is represented on a computer screen with the leaves being depictable either separately or together on the screen.

According to a further aspect of the present invention there is provided a process colour reference chart or target comprising one or more base process colours being arranged so that the chart or target can locate adjacent proof or print media for comparative purposes.

Typically the process colour reference chart or target is in the form of a template or key being configured to overlay the proof or print media and having a cut-out portion located adjacent each of said base process colours.

Alternatively the process colour reference chart or target is designed to be printed on the print media. Generally the base process colours include 100% process cyan, 100% magenta, 100% yellow and black vignette together with process trap colours such as 100% cyan/50% magenta, 100% magenta/100% yellow, and 50% magenta/100% yellow.

According to a further aspect of the present invention there is provided a process colour tuner comprising one or more transparent portions of a process colour of a specified half-tone dot density, the colour tuner being designed to overlay at least one selected process colour whereby a tonal variant of the selected process colour is presented.

Typically the selected process colour is taken from a process colour selector chart such as that disclosed herein. Thus, by varying the make-up of the selected process colour according to the half-tone dot density of the transparent portion the tonal variant of said process colour can be obtained.

Preferably said one or more transparent portions consist of four (4) separate process colours cyan, magenta, yellow, and black each in varying half-tone dot densities.

Generally the colour tuner includes four (4) pages each dedicated to one of the process colours of varying dot densities .

BRIEF DESCRIPTION OF THE DRAWINGS

In order to facilitate a better understanding of the nature of the present invention a preferred embodiment of an inking standard, a process colour selector chart, a process colour reference chart or target and a process colour tuner will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a schematic representation of a process colour selector chart or an improved swatch book; Figure 2 is a schematic representation of a process colour reference chart or target shown both on the swatch book of Figure 1 and as a colour data file; and

Figure 3 is an exploded photographic representation of various leaves of the swatch book of Figure 1 together with the process colour reference chart or target. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in Figures 1 and 2 there is a process colour selector chart in the form of an improved swatch book 10. The swatch book 10 is conventional in its physical construction having a plurality of rectangular-shaped leaves such as 1A and IB overlying one another and pivotally coupled together via a pivot pin 2. The pivot pin 2 is located at one end of the leaves 1 and offset toward a corner of the leaves 1 so that "fanning" of the swatch book 10 reveals substantially the full swatch, for example 1A. The leaves 1 are bound using a frontmost and rearmost reinforced cover sheet 3A and 3B respectively being shaped identical to each of the leaves 1.

Each of the leaves such as 1A and IB of this particular embodiment of the improved swatch book 10 is dedicated to a selected process colour, for example simulated gold "172" having a CMYK make-up of 5, 25, 100, 0, tonal variants of the process colour, and metallic variants of the process colour and its tonal variants. The make-up of the tonal variants is mathematically related to the CMYK make-up of the process colour. In this example, the tonal variants are shown in decreasing 10% increments beginning with a 90% tonal variant and ending with a 20% tonal variant. The process colour is shown as a rectangular-shaped block or swatch at an end of the leaf 1A opposite the pivot pin 2 and the tonal variants are arranged as similar shaped swatches adjacent to one another in decreasing 10% increments with the 20% process colour located adjacent to the pivot pin 2. The process colour swatch and its tonal variants are represented by 4A and 5A in Figure 1. In the case of the simulated gold process colour "172" the 90% and 20% tonal variants have a CMYK make-up of 4.5, 22.5, 90, 0 and 1, 5, 20, 0 respectively. Each of the leaves such as 1A also includes the metallic variant of the process colour 4A and its tonal variant 5A. The metallic variant is produced in this embodiment by underprinting of the process colour and its tonal variants with the fifth colour silver. The metallic variants such as 6A are shown in the form of a thumb print alongside the corresponding process colour or its tonal variant.

The improved swatch book 10 also includes a secondary process colour 7A together with its metallic variant. The secondary process colour and its metallic variant are located adjacent their corresponding process colour at an end of the leaf such as 1A. The secondary process colour has a preset colour variation from its corresponding process colour based on their respective make-ups. For example, a secondary process colour of the simulated gold process colour "172" may be known as "+10K 172" or more simply "171" having a CMYK make-up of 5, 25, 100, 10.

The CMYK make-up of the process colour and its tonal variants are shown on the leaf alongside the corresponding colour. In this example, the percentage tonal variation for each of the tonal variants is also shown. The preset colour variation of the secondary process colour is shown according to the variation, for example "+10K" representing the addition of 10% black to the CMYK make-up. Thus, it will be appreciated that the swatch book 10 can be used for process colour selection by a designer which is both meaningful and accurately reproducible by a printer.

The improved swatch book 10 provides greater convenience for the computer-based designer where in this example some

2464 swatches are achievable from 448 primary process colour make-ups. It is intended that the swatch book 10 be made available both in a physical and digital form. The file containing the digital form of the swatch book may only contain information for the primary and secondary prime colours with other tonal variants being achievable by specifying the primary colour in conjunction with the designated percentage tint. The secondary prime swatch may include half-tone dot densities to depict a darker hue of the primary colour but is not limited to only variations of the black plates dot density. It will be appreciated that the reduced quantity of colours due to the primary make-ups in the computer colour file will give greater convenience to the computer based designer who will not have to scroll through thousands of colours to find their choice.

Known process colour swatch books such as those produced by PANTONE and the TRUMATCH swatch book disclosed in US patent No. 5,174,758 have provided colour choices created from an interpretation of the reproducible colour spectrum by offset printing. To achieve this an external colour source was used with four colour process being interpreted by PANTONE from their special pigment ink mixes and by TRUMATCH in selecting colour hues devised from the Munsell colour system. On the other hand, the improved swatch book 10 of this embodiment of the invention has created colour selection from working with the individual process ink colour hues as the distinctive source thereby creating an original colour spectrum including dot density specifications only achieved via digital means.

According to another aspect of the present invention the inventor has conceived an inking standard of specified process colours which has been empirically derived from corresponding process colours of proofs. The inking standard which according to the embodiment described is to be known by the acronym ISIS (International Scale Inking Standard) standardises process ink pigment hues with proofing materials. ISIS has isolated and depicted ink pigment hue choice to provide an accurate target to match to the proof and thus providing the printer with more assistance to match the proof accurately. This largely avoids the previous situation where the printer was left to their own resources to choose which ink to achieve the desired result and inevitably was influenced by the convenience and cost of inks and had no predetermined structure for making ^"the choice. This problem was highlighted with the advent of direct to plate printing where no accurate proof is supplied, increasing the difficulty for printers to know what is expected without the knowledge of a target for process pigment hue of the inks. ISIS introduces a new inking standard with a specified target for process pigment hue of the inks to facilitate improved predictability of how process colour make-ups will in fact print. In one example the Rapida 7080 series inks manufactured by Hostmann-Steinberg are compliant with the invention's ISIS inking standard.

As shown in Figures 2 and 3 and according to a further aspect of the present invention there is a process colour reference chart or target, or a process colour key 12 incorporated in a physical or digital form of the swatch book 10. The colour key 12 in its physical form is included in a leaf of the swatch book 10 as a series of die cut holes such as 14 located alongside a sequence of base process colours.

In this example the base process colours are cyan, cyan/50% magenta, magenta, magenta/yellow, 50% magenta/yellow, and yellow. The base process colours together with their corresponding die cut holes are shaped triangular. The colour key also includes an elongate rectangular cut-out 16 having blended base process colours located along its upper and lower edges. The colour key 12 can thus be positioned over the printed file to facilitate checking of proofs and "press pulls". Similarly the colour reference target can be provided as a colour key data file and can be located on computer artwork to check proofs and "press pulls". Thus proofs or "press pulls" can be viewed to verify pigments hue is within an acceptable range. The applicant intends to provide the improved swatch book 10 together with the colour reference target 12 free of charge from its website on the internet.

The digital form of the colour reference target or colour key 12 is designed to be placed on the printable area of the digital artwork outside the final trim area. The physical key-hold colour key 12 is configured to be placed over corresponding data visible on the proof or printed media. Thus, process colour hue match can be guaged.

According to yet another aspect of the present invention there is provided a process colour tuner (not shown) designed in this example to be used in conjunction with the improved swatch book 10. The colour tuner in one form includes four (4) transparent pages having four (4) respective base process colours printed in varying dot densities. Each of the transparent pages is configured to overlay any one or more of the swatches to show how the swatch would appear with that particular amount of dot density added to the swatches make-up. Thus, the colour tuner in conjunction with the swatch book 10 provides a significantly increased colour range when seeking to find a specified colour match. This effectively extends the range of colours available from the swatch book.

Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, the inking standard may vary from ISIS provided it allows the printer to accurately match process colour as it appears on the proofing system. The swatch book may vary from that described such as by the inclusion of a "dry trap" metallic silver under-printed as a thumbnail adjacent the primary and secondary process colours and their tonal variants. It is also the applicants intention to include a gloss varnish on the top half of each swatch.

All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be deterjnineci from the foregoing description.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. An inking standard of specified process colours, the inking standard being empirically derived from corresponding process colours of proofs whereby the specified process colours of the inking standard accurately replicate the proofs.

2. A method of process colour creation involving the steps of: selecting a process colour, having a specified makeup, together with tonal variants of that colour, the tonal variants each having a make-up which is mathematically related to the make-up of the process colour; and reproducing the process colour and at least one of its tonal variants based on the specified and mathematically related make-up of the process colour and its tonal variant, respectively, said reproduction being performed using an inking standard of specified process colours, said inking standard being empirically derived from corresponding process colours of proofs whereby the specified process colours of the inking standard accurately replicate the proofs.

3. An inking standard or method of process colour creation as defined in claim 1 or 2 wherein there are four (4) process colours namely cyan, magenta, yellow and black (CMYK) .

4. A method of process colour creation as defined in claim 2 further involving a step of reproducing a metallic variant of the process colour (s) and/or the tonal variants wherein the metallic variant is produced by superimposing the process colour (s) and/or the tonal variants on a 5^th colour silver.

5. A method of process colour creation as defined in claim 4 wherein production of the metallic variant involves underprinting of the process colour (s) and/or the tonal variants with the 5^th colour silver.

6. A process colour selector chart comprising a plurality of leaves or pages each being dedicated to a process colour having a specified make-up, each of said leaves or pages including a series of tonal variants of the corresponding process colour, the tonal variants having a make-up which is mathematically related to that of the corresponding process colour whereby in operation a selected process colour and its tonal variant can be reproduced based on the specified and mathematically related make-ups of the process colour and its tonal variant, respectively, said reproduction being performed using an inking standard of specified process colours, said inking standard being empirically derived from corresponding process colours of proofs whereby the specified process colours of the inking standard accurately replicate the proofs.

7. A process colour selector chart as defined in claim 6 represented in the form of a swatch book having a series of leaves each dedicated to one of the process colours and its tonal variants shown as individual swatches.

8. A process colour reference chart or target comprising one or more base process colours being arranged so that the chart or target can locate adjacent proof or print media for comparative purposes.

9. A process colour reference chart or target as defined in claim 8 in the form of a template or key being configured to overlay the proof or print media and having a cut-out portion located adjacent each of said base process colours .

10. A process colour reference chart or target as defined in claim 8 designed to be printed on the print media .

11. A process colour reference chart or target as defined in any one of claims 8 to 10 wherein the base process colours include process cyan, magenta, yellow and black together with process trap colours such as 100 cyan/100 magenta, 100 cyan/100 yellow, 50 magenta/100 yellow, and 100 magenta/100 yellow.

12. A process colour tuner comprising one or more transparent portions of a process colour of a specified half-tone dot density, the colour tuner being designed to overlay at least one selected process colour whereby a tonal variant of the selected process colour is presented.

13. A process colour tuner as defined in claim 12 wherein said one or more transparent portions consist of four (4) separate process colours cyan, magenta, yellow, and black each in varying half-tone dot densities.