Content. 9 The limitations of Prinect Image Control About these Guidelines 4

Content 1 About these Guidelines 4 9 The limitations of Prinect Image Control 24 2 Fundamental rules and hints for proper measurement 5 3 Features of Prinect Image Control 6 3.1 The key issues in brief 6 3.2 How Prinect Image Control works 7 4 Measurement principle 8 4.1 Color measurement 8 4.2 Color deviation ΔE 8 4.3 Density measurement 9 4.4 The benefits of spectral color measurement 9 4.5 Density and dot area measurement 10 5 Generating follow-up recommendations 11 5.1 Defining image areas as a reference 11 5.2 Storing color sets in the color archive 11 5.3 Ensuring of reference values 12 5.4 Generating follow-up recommendations 12 5.5 Changing reference values 13 5.6 Reasons for an incorrect deviation display 13 10 Sample jobs 25 10.1 CMYK job with text in special color 26 10.2 CMYK job with frame in special color 27 10.3 CMYK job with frame in two special colors 28 10.4 CMYK job with defined corporate color 29 10.5 CMYK job with high text component 30 10.6 Copy image area in CMYK with frame in CMYK 31 10.7 Copy image area in CMYK with frame in special color 32 10.8 CMYK and special colors within the image 33 10.9 Job with special colors only, using color control strip 34 10.10 RJob with special colors only, using image control 35 10.11 CMYK job with different special color areas in solid and screen 36 10.12 CMYK job based on a previous OK sheet (partially or completely) 37 11 Glossary 38 6 Control methods 14 6.1 Using control elements 14 6.1.1 Using color control strip 14 6.1.2 Using color control blocks 14 6.2 Measurement within the image 15 6.2.1 OK sheet 16 6.2.2 Use of copies 16 6.2.3 Multi-color image areas 17 6.3 Which control method to use & when? 18 6.4 From make-ready to production run 18 7 Data management with Prinect Image Control 19 7.1 Data archives 19 7.2 Job protocol database 20 8 Prinect Image Control modules 21 8.1 Memory Plus the extended memory 21 8.2 Color Interface the way to the ICC profile 22

4 Prinect Image Control About these Guidelines 1 About these Guidelines These guidelines provide background information designed to make it easier to use Prinect Image Control. They highlight individual functions and features of Prinect Image Control and the applications for which these could be used. The practical hints summarize important information. They have a grey background. The guidelines do not deal with the individual operating buttons of Prinect Image Control in detail. Information on individual operating steps can be accessed using the Help function of Prinect Image Control or can be found in the operating instructions. The Help function can be used by the operator when he is working on the unit. The particular help is available based on the main menu which s currently being used. If you are currently located in the color archive, for example, you will be able to access information to create a color set. The Heidelberg logo button can be used to access the Help function.

Fundamental rules and hints for proper measurement Prinect Image Control 5 2 Fundamental rules and hints for proper measurement The following section sets out the key rules to ensure proper measurement and color control. Basic principles Prepare the press and Prinect Image Control (color archive, measuring conditions and ensure valid calibration). Prepare a color set(s) based on standard material and standard inks With every job Use presetting data from PPI/CPC31 or repeat job, if available. Use pre-inking 1 or 2. Do not pull the sheet to be measured too early as this can result inaccurate follow-up recommendation. Take note of the green light function on the Prinect CP2000 Center. Manual intervention should not be conducted between two follow-ups. Since measurements are performed without polarization filter, the printed sheet must be measured as soon as possible after sheet removal to ensure a stable measurement and color control. It is generally a good idea to stop the press during the make-ready steps rather than leaving it on idle speed. This retains the ink profiles in the inking unit. Goals If preparations are performed properly, the measurement of the first sheet pulled should show a color difference of ΔE < 8 (average value). With larger color deviations, the characteristic curves presetting should be optimized. If the presetting is OK, a color deviation of ΔE < 3 should be achieved within two to three follow-up recommendations. Correct measurement and control can only be assured if the inking/dampening units rollers are set correctly and the dampening solution supply to the plate is optimized.

6 Prinect Image Control Features of Prinect Image Control 3 Features of Prinect Image Control 3.1 The key issues in brief Prinect Image Control is an external color measurement system to monitor and control the printing quality. It is the only system worldwide which is capable measuring the entire printed image spectrophotometrically. Key features Up to four printing presses can be connected online to one Prinect Image Control unit. Prinect Image Control can be integrated into the workflow using a network link. Each measurement per side takes less than 30 seconds. A 70 100 cm print sheet can be measured in its entirety by breaking it down into 160,000 measuring points. This enables the print quality to be assessed over the entire print sheet. One measuring point is approx. 2.0 2.4 mm in size. For each ink zone, there are approx. 5,000 measuring points on a 70 100 cm sheet. This means that the measurement is far more extensive than merely viewing a color bar. The quality of the production run can be documented by printing out or storing the relevant job protocols. Repeat jobs can be saved in the job database. The unit can be used to measure test forms, to export data to generate an ICC profile and for process calibration. Through Remote Service, Heidelberg branches can access the unit via a modem connection if servicing is required.

Features of Prinect Image Control Prinect Image Control 7 3.2 How Prinect Image Control works Brief description of a measurement: 1. The sheet is broken down into 520 columns and 310 rows during the measurement process. All the cells (measuring points) are displayed in order of measurement. 2. The light returned at the measuring points is passed into a spectrophotometer where it is broken down into its spectral colors. 3. The computer uses the spectrum of each measuring point to define the Lab 1 and unpolarized density values. 4. By comparing the colorimetric values which have been measured with the reference values entered earlier, the necessary corrections (ΔF) can be calculated and transferred by Prinect Image Control to the Prinect CP2000 Center. 5. The Prinect CP2000 Center passes the follow-up recommendations to the ink fountains of the individual printing units where they are immediately implemented. 1 The correct notation is L*a*b*. Lab will be used throughout this text by way of simplification. Printing press Prinect CP2000 Center Computer/PC Spectrum 380 nm 720 nm Lightsource Spectrometer Printed sheets The Illuminant and Standard observer parameters should be preset to D50 and 2 in accordance with DIN ISO 13655.

8 Prinect Image Control Measurement principle 4 Measurement principle This section deals with the principles for measuring with Prinect Image Control. It only touches briefly on the basics of colorimetry. More informations in our brochure "User Guide: Introduction into Colorimetry and Spectrophotometry" (www.heidelberg.com). 4.1 Color measurement A Lab value can be calculated from every color spectrum. This Lab value represents an unique color impression. The following example shows how a color is assigned to its spectrum and the Lab values calculated from it. The conversion was defined by the CIE commission. CIE stands for Commission International de l Eclairage. In English: International Commission on Illumination. S (λ) L = a = 59.4 56.7 b = 49.3 400 500 600 700 nm 4.2 Color deviation ΔE The Lab color space is matched to the perception of the human eye. Color deviation which is perceived as being of the same intensity has the same distances in all color tones. This color deviation is known as ΔE (Δ = delta ). The L value describes the lightness; a and b represent position on the RED-GREEN axis and YELLOW-BLUE axis respectively. ΔE < 0.2 not visible deviation White 0.2 0.5 very small deviation 0.5 1.5 small deviation 1.5 3.0 fair deviation 3.0 6.0 clear deviation 6.0 12.0 large deviation Actual > 12.0 very large deviation Reference

Measurement principle Prinect Image Control 9 4.3 Density measurement Color density measurement primarily involves measuring the intensity of a printed color. The density value depends on the thickness of the ink film printed, the color filters used (red-green-blue filter) and the use of polarization filter. It is also possible to measure the density of special colors, although this is not sufficiently reliable. Range of density measurement with magenta filter 400 500 600 700 nm Range of density measurement with cyan filter 400 500 600 700 nm Range of density measurement with yellow filter 400 500 600 700 nm An unpolarized density value (in accordance with DIN 5033) is ensured by Prinect Image Control based on the spectral measured values. The polarized density display is calculated as a theoretical value. 4.4 The benefits of spectral color measurement The following example shows two entirely different colors. They can be differentiated using spectral color measurement, while the density measurement is unable to detect any deviation in color as using and displaying the highest density reading only. The same filter color (yellow complementary filter) is used for measuring the density of both colors.

10 Prinect Image Control Measurement principle In each case, spectral color measurement examines the entire spectrum of the colors. The Lab values that are calculated are used to determine the color deviation of ΔE = 114.4 between the two colors. Range of density measurement with yellow filter D = L = a = b = 1.60 60.2 56.8 62.9 Color sample HKS 8 Spectrum of HKS 8 400 500 600 700 nm Density and Lab values D = 1.60 Color sample HKS 65 Range of density measurement with yellow filter Spectrum of HKS 65 400 500 600 700 nm L = 59.4 a = - 56.7 b = 49.3 Density and Lab values Densitometric measurements are color blind. This means that a specific hue can only be measured using spectral color measurement. 4.5 Density and dot area measurement In essence, ink film thickness (color density) and dot gain define the color impression. In the color control process, the only target parameter varied and/or controlled is the ink film thickness. The dot gain is also influenced by this process. The dot gain is calculated using the Murray-Davis equation (from density values). 2.5 2.0 1.7 1.6 1.5 FOGRA 0% 0 10% 1.4 20% 1.3 0,1 1.2 30% Color density in full-tone D V 1.1 1.0 0.9 Dot area A 40% 50% 60% 70% 0.2 0.3 0.4 Color density in screen D R 80% 0.5 0.8 0.6 90% 0.7 100% 0.8 0.9 1.0 0.7 1.5

Ink fading Generating follow-up recommendations Prinect Image Control 11 5 Generating follow-up recommendations 5.1 Defining image areas as a reference A measuring run basically involves capturing all image areas of a sheet, even if only individual areas will be used as references later on throughout the production run. Follow-up recommendations are determined as soon as measured values and reference values for a sheet are available for comparison. Since inking can only ever be set on a zonal basis, follow-up recommendations only ever apply to one particular ink zone. This means that diverse areas can serve as a reference for calculating the follow-up recommendations: a) All image areas on the printed sheet (e.g. from the OK sheet) b) Partial areas of a sheet (e.g. repeats, frames, etc.) c) Color control strips d) Combination of a c Individual ink zone 5.2 Storing color sets in the color archive In principle, a color set comprising B/C/M/Y can also contain any number of special colors. Three types of paper (glossy, matt, uncoated) are stored for every color set. The paper white that is used is saved in each color set. When creating a color set, the paper white must always be measured first. The color values are then loaded next. After ascertaining the target values of the scale, the Lab value of the Heidelberg gray patch (C70%/M60%/Y60%) can be optionally stored; this then serves as a reference for the gray patch measurement (CMY). Only color values from natural samples can be loaded into the database.

12 Prinect Image Control Generating follow-up recommendations 5.3 Ensuring of reference values The term color sets refers to colorimetric default values of primary, (process) and special colors. As different types of ink have different printing and colorimetric characteristics, these have to be stored separately in the Prinect Image Control color archives. This means that a test print with the particular ink/paper combination has to be evaluated. The Lab values from the process standard for offset printing (or DIN ISO 12647-2) can also be used as the basis for this evaluation (see table below). Furthermore, lab proof strips or existing color samples can be loaded. Gray patch measurement: If the values for the color set are defined according to the procedure above, the values for the gray patch should also be loaded. Values for black substrate Paper type 1 + 2 4 glossy and matt coated white offset uncoated L* a* b* L* a* b* Black 16 0 0 31 1 1 Cyan 54 36 49 58 25 43 Magenta 46 72 5 54 58 2 Yellow 88 6 90 86 4 75 Red (M+Y) 47 66 50 52 55 30 Green (C+Y) 49 66 33 52 46 16 Blue (C+M) 20 25 48 36 12 32 Measurement in accordance with DIN ISO 13655, D50 illuminant, 2 observer, 0/45 or 45/0 geometry. 5.4 Generating follow-up recommendations If the reference values have been selected from the color archive, the first production run measurement can begin. The measurement system first of all performs a position measuring run which records the sheet size and sheet position (drive side/operator side). Then the image areas to be used for the color control process (reference/actual comparison) have to be defined. During the image measurement process, it is possible to scan in e.g. samples (size 1:1) through the submenu Image Area from Sample. A follow-up recommendation per ink zone is calculated immediately after the measuring operation.

Generating follow-up recommendations Prinect Image Control 13 5.5 Changing reference values If modifications for the target reference values are required during the color matching process, these can be done by changing the percentage. The unit automatically calculates the corresponding Lab value and displays the color distance ΔE. Zonal OK areas, for example, can be adopted and/or others adjusted during color matching. 5.6 Reasons for an incorrect deviation display In a few rare cases, Prinect Image Control will output high color deviations (see image) even though the print looks to be fine. This can be due to a number of causes: Wrong color set and/or wrong paper white has been selected Printing ink deviates from the color set displayed by a high ΔE 0. Different print conditions Wrong measuring conditions selected. If the measuring conditions and color set are set correctly and there are still large deviations, the reference values should be checked. All possible steps for reference value correction should only be performed in stages and in a well-directed manner. Changes in the reference value during the production run can lead to color fluctuation.

14 Prinect Image Control Control methods 6 Control methods 6.1 Using control elements Using control elements can be subdivided into control using color control strips and, for example, color control blocks distributed as required. 6.1.1 Using color control strips Using color strips is easy. It is very well suited for the make-ready of a job if no OK sheet is available. By measuring and controlling solid patches, a color set is required that contains the L*a*b* values for all printing inks and the paper white. With gray-patch control (gray balance patch C 70%, M 60%, Y 60%), the operator must ensure that the value corresponds to the appropriate color set. If problems are encountered with the gray-patch measurement, it should be ensured that the values of the dot areas are reproduced on the plate correctly. Control using color control strips also supplies values for process monitoring. These can include: Dot gain, slur/doubling, ink trapping. The illustration shows a section of a color control strip. We can see the solid patches for cyan, magenta, yellow and black and the gray patch (CMY). A line screen is also displayed to determine slur and doubling errors. The individual period repeats over all the zones of the print sheet. Prinect 4GS Dipco 2.0 Format 52 2003 Heidelberger Druckmaschinen AG 7 8 6.1.2 Using color control blocks Color control using color control blocks is very similar to control using color control control strips. In both cases, particularly developed control elements are used for the color control. The difference between the two procedures lies in how these control elements and their patches are arranged. The color control strip is positioned horizontally and repeats periodically over the entire sheet. Color control blocks can be positioned either horizontally or vertically. They do not repeat cyclically and can be applied to any point on the sheet. However, color control cannot take place in an area where no color control blocks are located. Thanks to their structure, color control blocks are particularly well-suited for print checks in packaging printing, for example, since they can be applied extremely well to the trim between the individual repeats. The predefined color control blocks can be used to check the various important printing parameters. The following blocks show different control patches.

Control methods Prinect Image Control 15 1 color contol block for checking solid patches. 2 Color contol block for checking the solid, 70% dot gain and slur/doubling errors. 3 Color contol block for checking the solid and 25%, 50% and 75% dot gains. 4 Color contol block for checking the solid and 40% and 80% dot gains. Color contol blocks 2 to 4 are available for all colors of control block 1. 6.2 Using image measurement Control using image measurement has the following benefits over control using color control strips and/or color contol blocks: Far more measured values are obtained per zone (approx. 5,000 per zone on a 70 100 cm sheet) as when using control elements. Since the measured values are averaged over the circumferential direction, they are more informative than measured values obtained at just the start of printing or just the end of printing. All tonal values of the print image are captured in the measurement and taken into account in the control procedure. Control is performed primarily on the basis of the print image, i.e. the object that will be sold and not the marginal areas. In principle, image control without color control strip is possible. Although this means that paper can be saved, it is then no longer possible to monitor the process parameters. Compared to control using color control strip and/or color control blocks, image control can sometimes appear less stable. The reason for this is not to be found in the quality of the control process, but rather the fact that process-related fluctuations are more recognizable. The following processes are supported for image control: OK sheet Image areas Multicolor (homogeneous) image areas The following pages look at these procedures in detail.

16 Prinect Image Control Control methods 6.2.1 OK sheet There are two options to make-ready a repeat job: a) Load the job from the job archive. This procedure reduces the make-ready time, the amount of waste and ensures the use of the same measurement conditions. b) Scan in the values of an approved OK sheet. There are three options for adopting the OK sheet: a) Entire sheet b) Color control strip c) Partial OK areas of the sheet During image control, only the measuring points that satisfy the following requirements are included in the control process: The measuring points are located in image portions that are at least 6 6 mm. The color component in the image area to be controlled has to display sufficient ink coverage for each of the individual colors. The areas to be controlled consist either of process colors or a maximum of two special colors in a composite print. The example opposite shows a classic job for control using the OK sheet. The example shows screen tones constructed from process colors, and a full-tone frame in the special color blue. 6.2.2 Use of copies Color control using the function Copy Image Area is always employed when there are multiple copies of the same type on the sheet. The illustration shows a printed sheet that is ideal for control using copies. With this type of control, the color of a copy is defined as the colorimetric reference. A Lab reference value is generated for each measuring point on this copy. These reference values are transferred to the remaining copies. When measuring the next sheet, the follow-up recommendations are generated from the deviation between the reference values and the actual values, meaning that the best possible color match could be achieved for all selected copies.

Control methods Prinect Image Control 17 Mixed forms (several different copies one after another) can be applied as a reference value. When using this method, the image area must satisfy the following requirements: There are several identical copies on the print sheet. These can be rotated either by 90º, 180 or 270. The color component in the image area to be controlled has to display sufficient ink coverage for each of the individual colors. The measuring points are located in image portions that are at least 6 6 mm. The areas to be controlled consist either of process colors or a maximum of two special colors in a composite print. 6.2.3 Multicolor image areas Control using multicolor image areas (hues from process colors or a maximum of two special colors) can always be used if there are homogenous screened or solid areas on a sheet. The graphic shows a printed sheet which is suitable for control using homogenous image areas. The gray area is made up of process color separations. A Lab value is defined for this image area and used for control. Homogenous image area When using homogenous image areas, the image must satisfy the following requirements: The measuring points are located in image portions that are at least 6 6 mm. The color component in the image area to be controlled has to display sufficient ink coverage for each of the individual colors. The areas to be controlled consist either of process colors or a maximum of two special colors in a composite print.

18 Prinect Image Control Control methods 6.3 Which control method to use & when? Control using color control strips is ideal for getting to know Prinect Image Control. This method is very well suited for setting up jobs. Color control strips are perfect for low area coverages on a sheet and for text as well. Control using color control blocks is always ideally suited if blank areas are not located along the margins of the sheet, but rather at various locations on the sheet. A color contol block can be easily positioned in the blank areas. This situation frequently occurs in packaging printing. Color control using OK sheets is a standard control method for achieving stable results over long production runs. Color control using the function copy image area is limited to multiple-up sheets. This type of control is ideal for compensating and preventing color fluctuations across the printed sheet. Image areas can be saved in the database Image Area. Color control using multicolor (homogenous) Image areas is suitable if specific homogenous image areas need to be kept as constant as possible, e.g. when printing color swatches or corporate colors. All control methods can be combined as desired. 6.4 From make-ready to production run The process of printing a job is outlined below by way of example: 1.) Set up job. 2.) Check measuring conditions. 3.) Select color set and type of paper. These must agree with the material currently being used! 4.) Perform first measurement. 5.) Position color control strip. 6.) Adjust until the required tolerance is achieved. Perform any fine corrections that are needed. 7.) Define OK sheet. 8.) Cyclical measurement and release the follow-up recommendation. Ensure the press run is stable between measurements. Avoid pulling and measuring the sheet too early ( green light!). This procedure can change depending on the modules used and the type of job. Make-ready using color control strip and production run printing using the OK sheet function is only to be understood as illustrative in nature. In addition to make-ready using color control strip, make-ready can also be performed using color control blocks, repeat jobs (control using OK sheet). In addition to the OK sheet, color control methods in the production run can be performed using color control strips, color control blocks, image areas or homogenous multicolor image areas. All color control methods can also be combined with each other.

Data management with Prinect Image Control Prinect Image Control 19 7 Data management with Prinect Image Control 7.1 Data archives Prinect Image Control has various data archives. The individual archives are accessed during order processing on Prinect Image Control. The job and color archives can therefore be accessed when setting up a job. When defining a color control strip access is made to the color control strip archive. Changes to the archive in question are made via the Prinect Image Control Service menu. This menu can be used to select the relevant archive. The individual archives are presented in brief below. Job The job is saved under the job name and date. When loading a job, the precise measurement and control conditions under which the job was processed are restored. In this way, for example, the reference values of an OK sheet can be reactivated. It is only advised to save a job if a repeat job is anticipated since the archive has only limited capacity. Color This archive is used to save color sets. The saved Lab values for a color set are stored with the corresponding paper white each. If a color set is used on a different paper, Prinect Image Control indicates reference values other than those in the color archive. This is not a fault in the unit. Instead, the unit is attempting to create the same colors as on the original, taking into account the change of paper white. The first measurement matches the reference values to the newly calculated paper white. Press The press archive contains the most important data for all interfaced presses. This archive only has to be accessed when the machine fleet is changed or extended. Color control strip This archive stores color control strips and color control blocks. For greater transparency, it is possible to differentiate between color control strips and color control blocks that are used and those that are hidden or unused. This makes it easier to locate control elements when processing jobs since, when positioning the control elements, only the color control strip and/or color control blocks that are actually used are made available for selection. Color control strips and color control blocks can be loaded by disk or CD-ROM. Tolerances The Tolerances archive is used to save tolerance values in ΔE for the process colors, special colors and the complete image. Tolerance values are defined in percentages for the 70% screen patches, the slur and doubling elements and the density values. If the tolerance values are exceeded, this is highlighted in color. Tolerance values have no influence on determining the recommended color corrections

20 Prinect Image Control Data management with Prinect Image Control and follow-up recommendations, only on the deviation display. The tolerance classes narrow, average and wide are already predefined. These tolerance values can be changed as required and additional tolerances could be input as well. Database backup This function can be used to copy the entire database (at cyclical intervals if set appropriately), thereby preventing the possible loss of important data. If a connection exists to a network, a copy can be saved at any location in the network. 7.2 Job protocol database The Prinect Image Control Overview menu can be used to create five different job protocols. All job data are saved in an Access database. The protocols are created from this database. A trend protocol can be output in graphical or numerical form for a production run. It is also possible to output a production run overview. The zonal color for an individual sheet can also be viewed in graphical or numerical form. The trend protocol shows the average ΔE deviation of a sheet from the relevant reference value and can do so for each color. The production run overview protocol relates to saved tolerance limits and shows the percentage of measured sheets that are inside/outside these tolerance limits. The zonal color protocol lists the measuring results of the individual colors for the sheet last measured and does so for the relevant ink zones. It contains different measured values depending on the control type selected. When using color control strips or color control blocks, the measuring results for the relevant control patches are output. When using image as reference only ΔE deviation is displayed. Protocols can be saved locally or in the network. When saving them in the network in conjunction with the Proto Viewer add-on software, records can be accessed at any workstation of your choice. Each user can also develop his own evaluations using the Access data format. In addition to individual sample sheets, these protocols provide valuable documentation for convincing customers of consistently high quality in the production run.

Prinect Image Control modules Prinect Image Control 21 8 Prinect Image Control modules Modules refer to software add-ons to Prinect Image Control which can be used to optimize the workflow in the printshop. Different modules can be used depending on the printshop s size and structure. 8.1 Memory Plus the extended memory When repeat jobs are received, the operator can access the original job saved in the database. This database has storage capacity for around 250 jobs. The Memory Plus module can be used to save and manage several thousand jobs together with all important machine settings such as the job number, job name, paper format, production run and ink zone setting. The data volume for a job depends on the control type. For example, image control involves saving far more data than control via color control strips. The Data management with Prinect Image Control section provides further information on the Job archive.

22 Prinect Image Control Prinect Image Control modules 2 The idea of the ICC profile was developed by the International Color Consortium. 8.2 Color Interface the way to the ICC profile 2 All the devices involved in the production process (such as screen, printer or proofer) simulate the end product, the printed sheet. It is therefore useful to have a separate profile for each device which describes their gamut. Color Interface supports this profile generating process by generating color measurement values (L*a*b*) reliably and quickly. The Color Calibration test form has been particularly developed for generating and compensating those profiles. The illustration below shows the entire test form with all required measuring patches (in accordance with ICC guidelines). The relevant measuring areas are marked in red. The text shows the information supplied by the individual areas. The ink fading, color chart and dot gain areas are available in duplicate. Only one of the two areas is labeled in each case. Different images are provided for visual assessment purposes. The color charts supply the color measurement values for generating the profile. All measurement data is exported to the software specifically used for profile generation. The other parameter fields show the process parameters of the printing press. Color Interface generates an appropriate protocol for all process parameters. Prinect Image Control enables the user to create profiles and monitor production on a single unit. Prinect Image Control is ideally suited to analyzing test charts (IT8, ECI, etc.) as part of the color management process. The measurement operation lasts only 30 seconds and is therefore far superior to other measuring systems.

Prinect Image Control modules Prinect Image Control 23 Each output unit has its own gamut. The illustration shows the gamut for: a) Color photography b) High-quality offset printing c) Newspaper printing The aim of each profile generation process is to adapt a limited gamut (e.g. offset printing) to fit a larger one (e.g. monitor). Use of a profile and monitoring of the necessary parameters combine to ensure true-color results in print. 0.8 0.7 0.6 0.5 a b 0.4 0.3 0.2 c 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

24 Prinect Image Control The limitations of Prinect Image Control 9 The limitations of Prinect Image Control Prinect Image Control has been designed for a wide range of applications in offset printing. The following applications involve some limitations: Measurement and control of metallic inks Metallized printing substrates Transparent printing stocks Opaque, non-transparent printing inks Control with low area coverages The measuring points are located in image areas that are at least 6 6 mm. Text and lines as shown by the illustration should be controlled via color control strip. The measuring equipment cannot capture such small structures precisely enough. Comparison of measuring results If you wish to compare measuring results from Prinect Image Control with those from other measuring devices, it is important that the measuring conditions are identical in both cases. As of parameters such as density filter standard, polarization filter, standard illuminant and standard observer, the external measuring conditions such as the time elapsed between printing and measurement and measurement in wet and dry conditions must agree. Since Prinect Image Control does not have a physical polarization filter, measuring wet sheets with polarization filters may result in deviations between measuring results obtained using Prinect Image Control and those obtained from other devices. These deviations can occur as Prinect Image Control calculates polarized density values from the unpolarized measurement. Differences can also result from the calibration status of the particular measuring device. The Service menu of Prinect Image Control contains a function for monitoring the unit s calibration cycles. Prinect Image Control indicates every 3 months that it needs to be recalibrated.

Sample jobs Prinect Image Control 25 10 Sample jobs The following pages describe the procedure for setting up typical jobs using Prinect Image Control. There are many possible alternatives to the individual operations described. Consequently, the descriptions given can only hope to serve as a starting point for creating your own jobs and are not intended as an comprehensive description of the unit s capability. The headings of the individual sample jobs provide information on the structure of the images. This is further explained using an illustration. The process of setting up the job is then described step by step. As a general rule: If the adjacent areas of a color are smaller than 6 6 mm, control must be performed using color control strip or color control blocks. If the color areas are 6 6 mm or greater, it is possible to choose freely between all control types. Perform cyclical measurement and follow-up when carrying out control measurements. Ensure the press run is stable between measurements. Do not pull the sheet too early ( green light function).

26 Prinect Image Control Sample jobs 10.1 CMYK job with text in special color Color control strip for CMYK and special colors (e.g. Prinect 6S) Text in special color gray Image area in CMYK Control: CMYK and special color controlled via color control strip. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from sheet function. 4. Show the solid area of the special color, transfer the value to the printing unit and exit the menu. 5. Select the required color control strip from the list in the Color control strip Menu and position it as appropriate. Exit the menu. 6. The follow-up recommendations are displayed in the Overview menu. Note: The special color must be present on the sheet in the required hue for the Select color from sheet function. Otherwise it is possible to import Select color from sample or Select color from data base. It is also possible to input a Lab value for the special color using the Enter value function.

Sample jobs Prinect Image Control 27 10.2 CMYK job with frame in special color Color control strip for CMYK (e.g. Prinect 4GS) Border in special color blue Image in CMYK Control: CMYK controlled via color control strip, special color controlled in image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from sheet function. 4. Show the solid area of the special color and transfer the value to the printing unit. 5. Select the Special color solid areas button. (Solid areas in the hue of the special color flash.) 6. Adopt the value and exit the menu. 7. Select the required color bar from the list in the Color bar dialog box and position it as appropriate. Exit the menu. 8. The follow-up recommendations are displayed in the Overview menu. Note: The special color must be present on the sheet in the required hue for the Select color from sheet function. Otherwise it is possible to import Select color from sample or Select color from database. It is also possible to input a Lab value for the special color using the Enter value function.

28 Prinect Image Control Sample jobs 10.3 CMYK job with frame in two special colors Color control strip for CMYK (e.g. Prinect 4GS) Image in process colors Border out of two special colors printed as homogenous solids or screen solids. Control: CMYK controlled via color control strip, special color controlled in the image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from database function. 4. Select the individual special color from the database, assign it to the printing unit and confirm the special color by clicking Enter. 5. Once every printing unit has been assigned the reference value of the printed special color, exit the menu. 6. In the Edit reference values menu, select the Multicolor image areas button. 7. Select the Color from sheet button. 8. Show the composite print area of the special colors and confirm the hue with Enter. 9. Select the Special color layout button. 10. Select printing units whose colors are used to construct the hue, confirm with Enter and exit the menu. 11. Select the required color control strip from the list in the Color control strip menu and position it as appropriate. Exit the menu. 12. The follow-up recommendations are displayed in the Overview menu. Note: Areas with more than two special colors in the sujet cannot be controlled in the image.

Sample jobs Prinect Image Control 29 10.4 CMYK job with defined corporate color Color control strip for CMYK (e.g. Prinect 4GS) Background in corporate gray, image in CMYK Image in CMYK Control: CMYK controlled via color control strip and image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. Select the required color control strip from the list in the Color control strip menu and position it as appropriate. Exit the menu. 4. In the Edit reference values menu, select the Multicolor image areas button. 5. Select the Color from sheet button. 6. Show corporate color with reference coloring and confirm with Enter. 7. Select the CMYK color layout button, confirm with Enter and exit the menu. 8. The follow-up recommendations are displayed in the Overview menu. Note: The corporate color must be present on the sheet in the required shades for the Color from sheet function. Otherwise it is possible to import Color from samples or Color from database. It is also possible to input a Lab value for the corporate color using the Enter value function.

30 Prinect Image Control Sample jobs 10.5 CMYK job with high text component Color strip (e.g. Prinect 4GS) Print sheet with high text component and little image information Control: CMYK controlled via color control strip. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. Select the required color control strip from the list in the Color control strip menu and position it as appropriate. Exit the menu. 4. The control recommendations are displayed in the Overview menu. Note: Because of the low area coverage values for the images, the control recommendations for image control can be less reliable. For this reason, it is recommended for jobs with a high text component to use color control strip or color control blocks.

Sample jobs Prinect Image Control 31 10.6 Copy image area in CMYK with frame in CMYK Border in CMYK Image in CMYK Control: CMYK controlled via OK areas in the image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Edit reference values menu, select the Copy image areas function. 4. Leave the default function Image area from sheet activated. 5. Show the image area with the required coloring level. 6. Select the Search areas function. (All repeats that are found will flash.) 7. Using the Transfer OK-image area function the reference values will be transferred to all identically image areas. Then exit the menu. 8. The follow-up recommendations are displayed in the Overview menu. Note: Image areas must be present on the sheet in the required coloring level for the Image area from sheet function. Otherwise it is possible to import the coloring level for an image area using the Image area from sample, Image area from other side or Image area from CPC proof functions.

32 Prinect Image Control Sample jobs 10.7 Copy image area in CMYK with frame in special color Border in special color Image in CMYK Control: CMYK and special color, controlled in separate areas in the image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from sheet function. 4. Show the solid area of the special color with reference coloring on the print sheet and transfer the value to the printing unit. 5. Select the Special color solid areas button. (Solid areas in the shade of the special color will start flashing.) 6. Adopt the value and exit the menu. 7. In the Edit reference values menu, select the Copy image area function. 8. Leave the default function Image area from sheet activated. Show image area with the required coloring level. 9. Select the Search areas function. 10. Once all image areas have been located, transfer the color values for the target repeat to the located repeats using the Transfer OK-image area function and exit the menu. 11. The control recommendations are displayed in the Overview menu. Note: Areas with special colors and process colors must be defined separately from each other.

Sample jobs Prinect Image Control 33 10.8 CMYK and special colors within the image Color control strip for CMYK and special color (e.g. Prinect 6GS) Background in the special color, screen built CMYK image and special color, screen built and mixed with process colors. Control: CMYK and special color controlled via color control strip. Setup procedure: 1. Set up job and select color set for the process inks. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from sheet function. 4. Show the solid area of the special color with reference coloring on the print sheet, transfer the value to the printing unit and exit the menu. 5. Select the required color control strip from the list in the Color control strip menu and position it as appropriate. Exit the menu. 6. The follow-up recommendations are displayed in the Overview menu. Note: In the example, the process and special colors are overprinted in the same image areas. The image control can therefore not differentiate between areas with special colors and areas with process colors plus special colors on top. This means that adjustment recommendations for in-house control tend to be unreliable. For this reason, it is recommended for this type of job to use color control strips or color control blocks as control method.

34 Prinect Image Control Sample jobs 10.9 Job with special colors only, using color control strip Color control strip (e.g. Prinect 6GS) Image in special colors printed next to each other. Control: Special colors controlled via color control strip. Setup procedure: 1. Set up job, deactivating the CMYK colors button. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from sheet function. 4. For each special color, show a solid area with reference color on the print sheet (e.g. in the solid patch of the color control strip), transfer the value to the printing unit and exit the menu. 5. Select the required color control strip from the list in the Color control strip menu and position it as appropriate. Exit the menu. 6. The follow-up recommendations are displayed in the Overview menu.

Sample jobs Prinect Image Control 35 10.10 Job with special colors only, using image control Image in special colors (solid) printed next to each other. Control: Special colors controlled in image. Setup procedure: 1. Set up job, deactivating the CMYK colors button. 2. Perform first measurement. 3. In the Edit printing units menu, activate the Select color from sheet function. 4. For each special color, show the solid area with reference color on the print sheet and transfer the value to the printing unit. 5. Select the Special color solid button. (Solid areas in the hue of the special color flash.) Adopt the value for each printing unit. 6. The follow-up recommendations are displayed in the Overview menu.

36 Prinect Image Control Sample jobs 10.11 CMYK job with different special color areas in solid and screen Color control strip for CMYK (e.g. Prinect 4GS) Image in process colors (solid and screen) printed next to each other and/or overprinted. Background in special colors (solid and screen). Control: CMYK controlled via color control strip, special color controlled image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Printing unit basic setup menu, activate the Select color from sheet function. 4. For each special color, show the solid area with reference color on the print sheet and transfer the value to the printing unit. 5. Select the Special color solid areas button. (Solid areas in the shade of the special color will start flashing). Adopt the value for each printing unit with special color. 6. Select the Special color screen areas button and the relevant printing unit. (Screen areas in the hue of the special color will start flashing) 7. Adopt the area for each printing unit. 8. Select the required color control strip from the list in the Color control strip menu and position it as appropriate. Exit the menu. 9. The follow-up recommendations are displayed in the Overview menu. Note: The Special color screen areas function enables Prinect Image Control to differentiate between screen areas in CMYK and screen areas in special colors. The function does not allocate a target value to the screen area in special colors. When an OK sheet is generated, reference values are also assigned to the screen areas in special colors.

Sample jobs Prinect Image Control 37 10.12 CMYK job based on previous OK sheet (entirely or partially) Old OK sheet New printed sheet Only parts of the old OK sheet are identical to the new job. Control: CMYK controlled image. Setup procedure: 1. Set up job and select color set for the process colors. 2. Perform first measurement. 3. In the Edit reference values menu, activate the Copy image areas function. 4. Select the Image area from sample function. 5. Place the old OK sheet on the measuring table and perform a measurement run. 6. Show the required image areas. 7. Select the Search areas function. (All image areas that are found on the new print sheet will start flashing). 8. Once all image areas have been found, transfer the reference values to the found image areas using the Transfer OK-image area function and exit the menu. 9. The follow-up recommendations are displayed in the Overview dialog box. Note: The complete OK sheet can be regarded as a copy if the old OK sheet and new print sheet are identical. An old, non-yellowed label/sample can also be used as an OK sheet.

38 Prinect Image Control Glossary 11 Glossary Color management Method/system for coordinating the individual units and presses involved in the workflow from color image processing to finished print result. Color management is used to guarantee correct color reproduction from input to output, e.g. on printing presses. Densitometer A density measurement device. Reflective densitometers are used for the printing process. To determine the density, the result of a white measurement is set in relation to the measurement of the required color area. Density Density The degree to which an ink layer is impermeable to light. On a theoretical level, this is the relationship between a measurement on unprinted paper and a measurement on printed paper. Printing profile The graphical representation of the relationship between the dot areas of the prepress products, generally screen data and the associated dot areas (screen percentages) on the printed sheet. Dot gain Ink fading Term for the decline in the thickness of the ink layer in circumferential direction in offset printing. Color distance ΔE ΔE describes the difference between two colors and can be calculated as the distance of the Lab values between two colors. Ink film thickness/ink level The physical thickness of the applied ink. The ink film thickness essentially determines the density value of a color. Ink coverage The ratio of the area covered (with image elements) to the total area (full solid). The ink coverage is generally specified as a percentage. A distinction is made in print between the effective ink coverage calculated from optical measurements and the geometric ink coverage calculated from area measurements. Actual value The value actually measured for a sample. Reference value

Glossary Prinect Image Control 39 Metameric colors Colors with different spectra that have the same Lab values under a given illuminant and different Lab values under different illuminants. This is also known as metamerism. Nanometer (nm) Unit of length, 1 nm = 0.000001 mm. For example, a fine hair has a diameter of 0.020 mm, one thousandth of this would be 0.000020 mm, i.e. 20 nm. Standard observer 2º or 10º A test series is used to determine how the color perception of the average standard observer is linked to a specific color area. The 2 test setup reflects a typical situation for reading books and magazines. The 10 test setup simulates viewing of a billboard. 1 m 2 or 10 Polarization filter The polarization filter can be connected upstream of the density measurement. Polarization filters filter out the glare components of the light. This makes the measurement virtually independent of the sample s drying status. One disadvantage, however, is that the density of the sample changes when the polarization filter is used. Reference value Target value for a measuring sample. The aim of every control operation is to ensure the smallest possible deviation between the reference value and the actual value. Actual value Dot gain The difference between the dot area of the printed sheet and the dot area of the printing plate. Wavelength The physical length of a wave period. Wavelength