ColorThink Tutorials

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Several quick tutorials have been included to aid in the understanding of the different uses for the ColorThink toolset.

Contents 1 Compare two different printing processes using the Profile Inspector 2 Compare an RGB profile gamut with that of a CMYK profile 3 Evaluate Device Link Profiles 4 Determine Proofer Suitability by using 3D gamut comparison 5 Compare Image color data with a printer profile 5.1 A. Graph Image Data 5.2 B. Compare with print profile gamut 5.3 C. Apply press profile to image data 5.4 D. Colorize by Delta-E 6 Evaluating Profiles Using Color Lists 6.1 A. Neutral behavior on device 6.2 B. Neutral behavior of profile 6.3 C. Raw Data to Profile comparison 7 Evaluating Devices and Printing Processes using Color Lists 8 Other Tutorials

Compare two different printing processes using the Profile Inspector

1. Open two CMYK profiles from different printing processes (eg an inkjet profile and a press profile)
2. Note the visual differences between the color tabs for each of the primary colors.
3. Click-open the Maximum Black color tabs for each profile and visually compare the L values. Note how one may get considerably darker (lower L value) than the other.

Compare devices & printing processes (2D graph overlay, gamut differences, coated vs uncoated)

Compare an RGB profile gamut with that of a CMYK profile

(This illustrates a typical color management problem.)

1. Open Grapher in 2D mode by clicking on the 2D Grapher button in the Menu Bar
2. Drag a press or other CMYK profile onto the Grapher window
3. Drag a monitor profile over (or add ColorMatch from Add: menu)

Note the difference in shape between the gamuts of the two devices.

• Click-select each of the profiles in the plot list individually to see the gamut color differences.

Notice the gamuts do not fully overlap. You can see the press colors that are out of gamut for the monitor. Those colors will either not appear on the monitor (and could appear on the final output) or, if the RGB profile is a Photoshop working space, they will be clipped within Photoshop and the colors are illustrating possible press colors that are lost due to a small working space. Also, notice the monitor/working space colors that are outside the gamut of the press. These are colors that are stored in your system, (possibly) displayed on your monitor, but will not print without the press profile shifting to a printable color. (See below for methods on how to see the color shifts depicted with vectors.)

Evaluate Device Link Profiles

1. Open a device link profile in Profile Inspector
2. Click-open black tabs on source & destination

Black generation on a proofer may require additional CMY color to achieve the same shade. In many cases, however, the conversion of color through the Lab color space contaminates the black channel with unnecessary CMY ink. Use of a CMM such as the Imation CMM when building device link profiles with Profile Linker may solve some of these black contamination problems.

Determine Proofer Suitability by using 3D gamut comparison

* Open a the Grapher in 3D mode by clicking on the 3D Grapher button on the Menu Bar

1. Drag a press or CMYK proofing profile from elsewhere in ColorThink (or directly from the Finder) onto the Grapher.
2. Drag an inkjet profile on the same Grapher
3. Select the inkjet profile and:
4. Click “single color”
5. Click “smooth”
6. Slide the “Opacity” slider about half way across.

ColorThink will plot both profiles with one superimposed upon the other. By turning one of the profiles into a single color and making it transparent it is easier to tell them apart and also see where they intersect. Note whether or not the CMYK press profile is entirely contained within the inkjet profile. Any areas where the press profile is not contained within the inkjet profile represent colors which are available on the press but which will not proof properly on the inkjet. Choosing an ink set or media that increases the gamut of the proofing inkjet may help, otherwise you may need to look at a different proofing printer.

Compare Image color data with a printer profile

A. Graph Image Data

• Drag the “Demo Image” image file from the Demo Files folder onto the Grapher window.

ColorThink converts the image device data (RGB) to Lab using the image’s embedded profile (or the system profile if there is no embedded profile). The image is down-sampled to a maximum dimension of 100 pixels per side and then it is plotted.

B. Compare with print profile gamut

• Drag the “Demo CMYK Profile” (which is a simplified typical press profile) onto the Grapher window.

ColorThink will overlay the press profile onto the image data. Note the colors left out of the press gamut. These colors, while they exist in the file, are unprintable and will need to be shifted by the press profile in order to print.

• Try varying the opacity of the press profile or choose "wireframe" surface shading to see the image data that lies inside the press gamut.

C. Apply press profile to image data

1. Select the “Demo Image” plot item from the list of plot items
2. Choose “Vectors” for the “Plot As...” setting
3. Drag the same “Demo CMYK Profile” into the “Destination” box

ColorThink will “round trip” the image data by converting it to CMYK and then back to Lab. The differences between the pre-converted colors and the post-converted colors are shown as vectors.

Note how the out-of-gamut colors get mapped into the gamut of press to become printable. Try different rendering intents to see how the profile maps out-of-gamut colors as well as the color shifts that may occur in-gamut. (the demo CMYK profile contains the same table for all intents so may not be a good demonstration of this function)

• Option-drag the graph to enter inside the press gamut.

D. Colorize by Delta-E

1. Select the “Mini Bridge” plot item from the list of plot items
2. Select “delta-E color” for the “Plot Color”

ColorThink will colorize each vector according to its length – the amount of color shift or error. This color shift is measured by delta-E where 1 delta-E unit is defined as the smallest color shift perceptible to the human eye.

3. Select “delta-E colors” tab

4. Move the color sliders to set how you want the transitions between the delta-E colors to occur.

By setting the sliders you can customize ColorThink to your in-shop standards. Color shift analysis is then as easy as setting up one of the above tests and colorizing by delta-E. You can quickly see how much shift is occurring and decide whether it is an amount of error that will require device maintenance (like recalibration) or profile regeneration.

Evaluating Profiles Using Color Lists

A. Neutral behavior on device

1. Load the CMY or RGB neutral test from the Stunt Files folder. (Choose the type depending on your profile type.)
2. Apply a profile to the list by dragging it onto the Color List window to calculate color values.
3. Click on 3D Grapher to open new graph.

Note color shifts through neutrals. In the case of RGB and CMY test values what is shown is how equal RGB and CMY values will appear, NOT the ability of the profile to correct for this problem. Color shifts displayed effectively show raw device behavior, hopefully the profile corrects for this behavior. A calibrated device such as the Fujix Pictography should display even RGB values as neutral. This is an effective method of testing calibration of such devices.

B. Neutral behavior of profile

1. Load the “Lab neutral test” file from the Stunt Files
2. Click 3D Graph button to create a new 3D graph
3. Ensure the color list is selected in the list of plot items
4. Choose “Vectors” for the “Plot As...” setting
5. Drag your profile into the “Destination” box.

ColorThink calculates the “round trip” for the neutral colors. Any color shift is shown as vectors moving away from the vertical L axis. The highlight value of 100,0,0 is expected to darken to paper white and the shadow value 0,0,0 is expected to lighten to paper/ink black. Any other shifting or “spiraling” of the neutral colors indicate a profile which does not render neutrals well and should be rebuilt or edited.

C. Raw Data to Profile comparison

1. Load raw measurement data from profile-building application – please refer to the software manufacturer’s manual to determine where to find this data or how to export it. Please refer to the “Color Lists” section of this manual for information regarding which file formats are supported by ColorThink.
2. Click 3D Graph button to create a new 3D graph
3. Drag the profile you built with the raw data into Grapher window (from Profile Manager, Profile Inspector, or directly from Finder)
4. Graph the data
5. View the data noting how many data points lie inside the profile wireframe structure. Points outside may not have been included in profile as they may be errors, etc.

Evaluating Devices and Printing Processes using Color Lists

Monitoring device behavior – drydown (ink curing)

1. Print a color target from the device in question
2. Read a small set of the colors immediately
3. Wait 30-60 minutes
4. Read the same small set of colors
5. Open both sets of colors with ColorThink
6. Drag the first measurement list to the Grapher
7. Click “Vectors” in the “Plot As...” area
8. Drag the second measurement file into the “Destination” box

ColorThink plots the color differences between the two files as vectors. This 3D plotting technique is a very powerful way of determining color shift amounts and directions.

This technique can also be used to Compare:

Color Measuring Instruments

• Instruments from different manufacturers
• Instrument settings and filters (eg UV cut-off filters)

Media and Inks

• Media differences
• Inkset Differences
• Ink fading
• Ink Drydown

Output Devices

• Monitor device behavior over time – observe if wear, temperature, humidity, and so forth changes color
• Determine maintenance requirements by observing when enough device shift occurs to warrant recalibration, cleaning, replacement and so forth
• Two different printers – observe if exact same models behave similarly enough to use the same device profile

Stunt data: Two measurement data files have been supplied to test the vector plotting capabilities.

• Matchprint data read using the SpectroLino/Scan with and without the Polarization filter.

- Open one of the files (or simply drag it straight into the Grapher from the Finder)

- Choose “Vector” for the “Plot As...” setting

- Drag the second list into the “Destination” box.

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Other Tutorials

Dennis Dunbar has a detailed tutorial covering how to use images in the 3D Grapher to compare working spaces, like AdobeRGB and ProPhotoRGB. His blog post is here: DunbarDigital.com/blog

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This is the end of the ColorThink2.2 manual

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