Profile Your Press with GMG SmartProfiler
GMG SmartProfiler helps you to create printer calibrations and color profiles for digital and large format printers. This optional feature extends GMG ColorServer with profiling functionality. Thanks to the step-by-step structure, any user can calibrate, recalibrate, and profile their digital and large format printing systems without expertise in color management.
Generally, you start with creating a new printer–medium combination, which will be saved as a SmartProfiler resource on the server. This resource holds all information required to calculate a profile such as measurement data and printer-medium definition you provide. From this SmartProfiler resource, the system automatically publishes a hotfolder and corresponding color profiles within GMG ColorServer. You can then drop input documents into the hotfolder and GMG ColorServer will automatically optimize them for the profiled printer–medium combination.
GMG SmartProfiler will guide you through this process. Some steps require printing and measuring of test charts.
This video shows how to start profiling with GMG SmartProfiler.
In GMG ColorServer, go to the Resources tabbed page > SmartProfiler, and click New to create a new printer–medium combination. Follow the procedure in the GMG SmartProfiler form step-by-step. (If SmartProfiler is not visible, check the connection from the client to the server and to GMG OpenColor.)
Check the connection to GMG OpenColor
This video shows how to check the connection to GMG OpenColor in the status bar.
A green status icon on the bottom left indicates that the client has established a direct connection to GMG OpenColor.
If this is not the case, check the network connection between the computer the client is running on and the computer GMG OpenColor is running on. If it is fine, check the connection settings on the server (see "Connect GMG OpenColor to GMG ColorServer").
Prepare your press
Make sure the press is loaded with the print medium, print mode, and any other hardware configuration that you want to use in production . The profiles and resources you are going to create in the following are optimal only for this configuration. If you change settings on the press later, the press will show different characteristics and you will need to repeat the process to update the resources accordingly.
Make sure the press has all the maintenance it needs and produces stable print results. If the printing process itself is not stable, the best profiles won't do any good. Printing test images and test charts is a best practice to evaluate the printer stability.
Likewise, the measuring device should also be clean and produce stable measurement results.
Deactivate color management in the DFE
Deactivate all color management settings in your Digital Front End (DFE). The color management will be done by GMG ColorServer. If you have two systems for color management in place at the same time, you will most likely not be getting ideal results. To check that the color management is switched off, print a gray color using only CMY channels. Check that no Black was used. Print Black and check that no CMY was used.
Define Printer & Media
This video shows how you to define the specific printer, print mode, and media type for the profile you are going to create.
In the first step, you will enter information on the characteristics of your press. At the end of the entire process, GMG SmartProfiler will create profiles and other resources for the specific printer, print mode, and media type you have used during the process. We call this the printer-medium combination. So enter a Project Name properly describing this particular printer-medium combination. This name will be used for naming all dependent resources. Therefore, a proper name will be important for you to find those resources later.
Select the Printer Type that best fits your digital press: Select Toner Based Digital Press for xerography, laser printers, and printers with liquid toner such as the HP Indigo. Select Inkjet/LFP for Large Format Printers (LFP) and inkjet systems such as UV and solvent. GMG SmartProfiler will use this information to select the ideal profiling settings for this type of printers. Then enter the name of your printer under Printer Name and specify the Print Mode below.
Please enter your production medium under Media next. This information will later help you recall the specific printer-medium combination for which the profile was created.
The following information about Media Category and Media Type will be used by GMG SmartProfiler, and it will also be forwarded to GMG OpenColor. By selecting the category and specifying whether your media is Uncoated, Coated, the prediction results for characterizations will improve significantly, especially for uncoated media with a low TAC.
Hotfolder
This video shows how to define the folder structure for the automated processing.
In this step, you define the input and output folders. From the two Hotfolder Location lists, select Default. (If the lists are empty, you will first need to configure the Hotfolder Locations in the Hotfolder Service Configurator (see "Define the hotfolder location")).
The default settings for the input and output folder.
The Output folder will be created as a subfolder of your main hotfolder. You can see the computer host and folder location in the Hotfolder Service Configurator. If you kept the default settings, it will be C:\Hotfolders\ on the local machine. So the complete folder path will be C:\Hotfolders\ISO Coated - My Digital Press - CMYKOGV\Output in this tutorial.
During the profiling process, all test charts that you need to print on your press will be sent to the output folder. Please make sure that this folder is used as an input folder for your DFE. Of course, you can also manually copy the files from this folder to your DFE.
When working with PDF files that contain overprinting or transparent objects, it's important to use flattening to achieve accurate color results. To enable flattening for your hotfolder, check the box under PDF Flattening > Use Flattening for PDF Processing.
Once flattening is enabled, the project's Input Color Space will be used as target color space for the normalization. This means that CMYK objects will not be normalized, while RGB objects will be normalized to the project's CMYK color space. The Raster/Vector Balance will be automatically set to 90% to reduce processing times (see "Flattening Settings").
The marked checkbox enables flattening for a hotfolder.
Ink Configuration
This video shows how to define the ink configuration and how to find the ink limit.
In this step, you will define the current ink configuration of your press. CMYK is always used. If you have a "SmartProfiler Multicolor" license, you can add up to three further inks. You can select from typically used inks such as Blue, Green, Orange, Red, and Violet. In this tutorial, we are using Orange, Green, and Violet. Another typical example would be Red, Green, Blue. You can select any other combination matching your ink configuration, for example, Orange, Green, Blue.
Finished ink configuration. The settings are locked. If you need to change them, you can click the Edit button.
What if the inks have a different name in the DFE?
For each ink, you can enter the name used by the DFE into the Alias box. Make sure the names are exact matches. The application will use the ink names as color channel names in the output PDF and in the profiles and resources. If you leave the box empty, the Ink name will be used directly, for example, "Orange".
Find the ink limit
If you don't know the ink limit for sure, you will need to print a test chart to determine it. A visual check of the printed test chart allows confirming or modifying the calculated total ink limit (TAC). If you see any effects of too much ink such as bleeding or gloss banding on the test chart, reduce the ink limit.
Click the Print button. GMG SmartProfiler will create a test chart PDF and send it to the output folder. Print the PDF on your digital press. (If the test chart does not show up in the output folder, check that the GMG ColorServer Service Monitor is running (see "Check the System").)
Evaluating the total ink limit. The image shows a part of the test chart. The number on top of a column shows the total area coverage (TAC) of the column.
Examine the patches on the printed test chart. Enter the highest value not showing overinking effects into the TAC box to keep the printer color space as large as possible.
You can scale the TAC test chart for printing in your DFE to increase the patch size for visual evaluation.
When you click the Save button, GMG SmartProfiler will create a test chart PDF to characterize the printer color space of your digital press in the next step.
Printer Color Space
This video shows how to measure the printable color space.
In this step, you need to print and measure a test chart to characterize the printer-medium combination.
How to print a test chart...
Test charts can be printed in GMG SmartProfiler from the Measurement view under Printer Color Space > Print & Measure.
- Under Measuring Device, select the measuring device that you want to use.
The test chart preview in the center changes to show the layout and color patches for your individual test chart. Depending on the test chart size and the media width of your press, the test chart might have several pages. - Under Patch Size, you can adjust the patch size to your needs.
- Under Media Size, you can adjust the media size to your needs.
Please make sure that the final test chart layout will fit on your medium. Adjust the patch and / or media size, if necessary.
- If you want to use transparent or metallic substrates, please activate the Add White Undercoat Layer checkbox.
With this option activated, a white undercoat layer is added to your test chart automatically. - Now you can choose how to proceed with the test chart PDF after its creation:
- If you want to send the PDF directly to your hotfolder's output folder and have it printed automatically, click the Printer button.
- If you want to save the PDF to a different location and print it manually later, click the PDF button.
If the press has been standing for a few minutes, we recommend you to print multiple copies of the test chart to warm the press back up again.
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Please allow the test chart to dry properly after printing, as an ongoing drying process might affect the color results.
Print & Measure dialog, before printing.
Let the test chart dry properly. If you are using a non-sheet fed measuring device, mount the test chart. Then click the button that is highlighted next (Add single measurement) and measure the test chart. Please follow the link for more information: Printing and Measuring Test Charts
When you are done with the measurements for all pages, click the arrow button on the left side of the upper toolbar to return to the SmartProfiler document.
Alternatively, you can also import measurement data.
Check the printer color space (gamut)
At this point, it is a good idea to have a look at the printer color space (gamut) to see whether the printer-medium combination fits your needs. You can check the gamut against the reference color space, which is ISO Coated v2 (39L) in this tutorial. You can also check for specific spot colors whether they can be reproduced with this printer-medium combination or whether there are out-of-gamut colors.
If the gamut is not sufficient, you might want to consider swapping the medium or even use a different press for a particular job.
Click the button Show gamut in GamutViewer.
GMG GamutViewer will show the measurement data as dots in a 3d Lab color space. You can turn it around with the mouse to view it from all angles. You can load a reference color space and/or enter Lab target values for a couple of spot colors. For example, you can look up the Lab values in one of the spot color libraries in GMG OpenColor.
In the screenshot, the reference color space ISO Coated v2 (39L) is depicted as colored lines. The printer color space is plotted as blue dots. A violet spot color is also shown on the right side. As you can see, the printer color space is larger than the reference color space. So we should not expect any problems when printing CMYK data. The violet spot color is clearly out of gamut. If this color is printed, there will be a visible difference between the intended color and the printed color.
Color Management
This video shows how define the color management settings and how to create a custom input color space in GMG OpenColor.
In this step, the most important choice you will need to make is the Input Color Space. This is the reference color space for your print jobs. If a job was already printed on a different machine, for example, on an offset press, or if there is a reference hardcopy proof, the print standard that was used with this offset press or that was simulated in the proof will now be the reference for your digital press. A GMG OpenColor project will need to be present for the described reference space in order to use it as the Input Color Space for your GMG SmartProfiler process. The input documents should be in this color space and have a matching output intent. RGB objects are directly converted to the printer color space, without normalization. You can choose from a couple of preinstalled input color spaces, for example, ISO Coated v2 (39L) - PANTONE® Solid Coated V4. All color spaces listed here are stored as projects in the GMG OpenColor database. In this tutorial, ISO Coated v2 (39L) is the input color space (see "Offset Print Sample").
Select the Separation Preset that fits the purpose of your printing process best.
For standard print production on a toner based device, select Production. No Black uses only CMY and might save toner on a toner based device with a click-based license.
For inkjet systems, you can choose one of the Ink Saving presets to reduce the ink usage and save costs. All relevant parameters such as GCR level and Black Start are then automatically adjusted accordingly. If you prefer a user-defined setting instead, you can readjust the relevant sliders manually.
All other settings are advanced settings and you don't need to worry about them right now. You can come back to them later if you have any problems with the print results.
What if I cannot find the right input color space on the list?
If you cannot find the right color space or if you are using a custom standard, you will need to create a characterization and a corresponding input project in GMG OpenColor first.
The input project needs to define CMYK and all spot colors you might encounter in the input documents. GMG OpenColor will calculate Separation Rules, which are basically a lookup table of input colors (spot colors) from the document and define how the input colors should be separated into the output inks of the digital press. These Separation Rules will be sent to GMG ColorServer and be stored as a spot color library under Resources > Spot Colors. GMG ColorServer uses it when processing jobs from the hotfolder that will be created by GMG SmartProfiler.
Please refer to the GMG OpenColor Online Help for more information: https://gmgcolor.com/support/help/opencolor/
Finalize & Publish
This video shows how to finalize the profiling with GMG SmartProfiler.
You are almost done now. GMG SmartProfiler has all the information it needs to profile your press. Just click the Calculate & Publish button.
GMG SmartProfiler will process the information and send it to GMG OpenColor. GMG OpenColor will calculate all required profiles and send them back to GMG ColorServer. Also, GMG SmartProfiler creates a hotfolder that uses all those profiles. All this is done fully automatically by the applications. This process usually takes several minutes and the client is locked during this time.
GMG SmartProfiler will show you a list of all created resources. All resources will be named after the name of the GMG SmartProfiler document. Please follow the links for detailed information on the resources and what you will need them for: