SprinterB Quality printing Color Management

Transcription

1 Application Note: #10 Date: June. 07, 2005 SprinterB Quality printing Color Management Table of Contents Introduction...2 SprinterB ICC Profiles...2 PPS RIP, Color Management Settings...3 ICC Profile Creator...5 Scanvec PPS Profile Creator Wizard...5 Appendix A Rendering Intents...17 Perceptual...17 Relative Colorimetric...17 Absolute Colorimetric...17 Saturation...17 Spot

2 Introduction To take full advantage of color management with the SprinterB workflow and to get the maximum quality output, it is recommended to build and use ICC profiles. ICC Profiles are simply look-up tables that describe the properties of a color space. The ICC profiles in the SprinterB workflow define the most saturated colors available in the SprinterB color space. SprinterB ICC Profiles The SprinterB PPS includes default ICC profiles for specific substrates or generic profiles. The default SprinterB ICC profiles can also be found on the Matan web site: 2

3 PPS RIP, Color Management Settings The use of ICC profiles takes place in the PPS RIP process. For using an ICC profile in the RIP process follow these steps: 1. Select the desired RIP setup. 2. Select Default Job Properties option from the Setup menu. 3. Select the Color Management Tab. 4. Check the Perform color correction check box. 3

4 5. Select Add from the Output profile popup menu. 6. Select the desired ICC profile. The selected ICC profile was added to the Output profile popup menu and was selected automatically. If you are working with a 3 rd Party Profile (a profile that wasn't made by the PPS), make sure that the Linearization table popup menu is set to None. If you are working with a PPS's profile, select the appropriate linearization profile. 7. Open the Advanced dialog using the Advanced button. 8. For the Input ICC Profile settings, use the default dialog settings unless you have the original input ICC profile. It is recommended to uncheck the Use embedded ICC profile check box. 4

5 For the Output ICC profile set the following Rendering intent : Bitmap Vector Text Gradient Perceptual Spot color Spot color Relative colorimetric These are recommended settings only. See appendix A for more details about the ICC rendering intent. Creating ICC Profiles In order to create an ICC profile, a colorimeter device is required. The ICC profile can be created using the PPS wizard or by any other ICC profile creator applications (e.g. GretagMacbeth ProfileMaker). Scanvec PPS Profile Creator Wizard Before starting, please make sure that no color management is activated. In other words a new ICC and Linearization Profile must be made from scratch. Below is a step by step explanation of the Profile creator wizard: 1. Select the Setup configuration that the ICC profile will be attributed to. 2. Open the Color Profiler dialog by selecting the Color Profiler option in the Setup menu. 5

6 3. Set the Setup configuration name, Media name, RIP resolution and the screen type and press the OK button. The main Color Profiler dialog will open. 4. Make sure the colorimeter device is connected to the computer and open the Device Setup dialog using the Device Setup button. 6

7 5. Set the connected device parameters. Each colorimeter type and model has its own setting. For example, Gretag Macbeth Spectroscan setting dialog look as follows: It is recommended to measure each swatch more then once if available in the colorimeter device. 7

8 6. Open the Find Ink Limit dialog by pressing the Find Ink Limit button. These settings are basically for ink printers so do nothing (leave the default dialog settings) and press the OK button. A Done text, beside the Find Ink Limit button will appear in the main wizard dialog. 7. Open the Linearization dialog by pressing the Linearization button. 8. Set the output linearization file name. The linearization curve generation is an important step in printer color characterization. The typical purpose of the linearization curves in conventional four ink printing is to compensate for dot overlapping and dot size variations and therefore to accommodate the non-linearity of the printing process. 8

9 9. You can create a linearization profile manually or by using a densitometer: Manual linearization profile (this section has been expanded in AppNote 11 Sprinter Manual Linearization Profiles.pdf) a. Uncheck the Use Densitometer check box. b. Create a new linearization file by using the New button. A successfully generated message will appear. The created linearization profile uses a straight linear 45 o degrees curve for all the separations and will not influence the print shades. c. Open the linearization curve by pressing the Edit button. d. Adjust the points on the curve by either dragging them up and down, or by selecting the labels on the X-axis and editing their values in the Output field. 9

10 The curve should not contain any points that fall below a previous value. If such a point is measured, edit the curve so that the point is above the previous point on the curve. Click Reset to return the curve to the original values. e. Press the OK button. For a more detailed description of this process, please refer to AppNote 11 Sprinter Manual Linearization Profiles.pdf 10

11 Measured linearization profile a. Select the size of the steps in the calibration target from the Steps list. The smaller the % increment, the larger the number of swatches that will be required in the target (Recommended 5% step). b. Check "Use Densitometer" to measure the linearization data with a densitometer. c. Click "Print Target" to output a target pattern d. Import the RIPped target to the Sprinter and print it. 11

12 e. Position the target on your measuring device and click "Measure". f. Click "Start". 12

13 g. Position measuring device to the target h. Once the measurement process is completed, click "Next". i. If desired, edit the curves. j. When finished click "OK". A Done text, beside the Linearization button will appear in the main wizard dialog. 13

14 10. Open the Find Multi-Ink Limit dialog by pressing the Find Multi-Ink Limit button. These settings are basically for ink printers so you do not need to do anything (leave the default dialog settings) and press the OK button. A Done text, beside the Find Ink Limit button will appear in the main wizard dialog. 11. Open the Characterization dialog by pressing the Create ICC Profile button. 14

15 12. Set the Number of swatches to 547 (do not use more then 547 swathes in a target. A smaller target with fewer swatches can be used). Set the Swatch size: to 13 x 10 inch (fit for the SprinterB media size). Press the Print Target button. A swatches target will be created according to the dialog settings and automatically will be ripped with the selected PPS setup. Each colorimeter device uses a different target type. The illustration below show a 547 swatches target for Gretag Macbeth Spectroscan colorimeter device. 13. Add the ripped target files to the SprinterB software and print the file. 14. Measure the printed target In the Characterization dialog press the Measure button and follow the wizard instructions. Each device has a different target type and measure steps. 15

16 15. At the end of the measuring process close the Data Measurements dialog using the Exit button and then close the Characterization dialog using the Close button. The newly created linearization and the ICC profile will be added to the job properties dialog. The use of the linearization trc file can be set to None. 16

17 Appendix A Rendering Intents In almost every design, there are some colors or shades that can not be printed by most digital printers. Instead of leaving these areas blank, the software enables you to define how you would like that color translated, so that your desired printer is capable of printing these shades. Perceptual Perceptual is best for photographic images. The relationship between colors in the original is scaled proportionally to fit the output device's color gamut. This intent scales all of the colors of the image, whether in the printer s gamut or not, until all colors are within gamut. Highlights, shadows and shading are well preserved. Relative Colorimetric Relative Colorimetric is best for images, such as logos, where the original file needs to exactly match the output. Colors that fall outside of the output device's gamut are converted to colors at the edge of the gamut, which may reduce the total number of colors available. For this reason, this intent should only be used when there are relatively few colors in an image. This intent moves only the color out of the gamut, to the nearest color in gamut along the same hue (so red doesn t shift to orange). Absolute Colorimetric Absolute Colorimetric works well for colors that must be matched as closely as possible. Unlike Relative Colorimetric, colors that fall outside the color gamut are included, but relocated relatively close to other colors. This intent moves only the color out of gamut, to the nearest color within the gamut, regardless of hue (so red might shift slightly to orange). Saturation Saturation is best for images where true color matching is not as important as vivid colors. Colors outside of the output device's gamut are converted to colors within the same saturation but with a different lightness. This intent may be used to boost colors within a photographic image. Ideal for eye-catching Point-Of-Purchase signage that benefit from bright, more vibrant colors. Spot Spot is best for devices with spot colors and vector images. This intent, which produces the greatest saturation possible, should only be used with non-photographic images. 17