THE COLORCHECKER PAGES (3/3)

Click to go to a section of interest:

Page-1: Attention ! Warning ! Important ! Read-me ! A brief presentation  ColorChecker charts formats / pictures New color specifications since November 2014 (New section - 2016/01) Where to buy? Page-2: ColorChecker data (RGB coordinates, spectral data, Excel tables) (Updated - 2016/01) Visual comparisons (BEFORE Nov. 2014 vs AFTER Nov. 2014) (New section - 2016/01) Visual comparisons (individual charts vs average) ColorChecker images (RGB and L*a*b*; 8/16-bit) (Updated - 2016/01) Do you want to provide some data? Page-3 (this page): Using the chart to auto-correct images or make ICC/DNG profiles Using the chart to analyze your camera's performance The problem with the ColorChecker SG (Updated - 2016/01)
BabelColor ®
Color Measurement and Analysis

Using the chart to auto-correct images or make ICC/DNG profiles

Because the ColorChecker patches cover a relatively large color gamut, not with a lot of samples mind you, one could think of using it to generate a correction profile, and the chart can effectively be used to generate an ICC profile or a DNG camera profile. It could be argued that making an ICC profile with a ColorChecker is foolish, but it is certainly better than no calibration at all. For many years it was possible to make scanner, monitor, printer and camera profiles using the ColorChecker with ProfileMaker Pro and MonacoPROFILER; unfortunately, it is only possible to make such profiles for printers in i1Profiler, the software that has replaced both ProfileMaker and MonacoPROFILER. Nowadays, the ColorChecker is more targeted ;-) for the creation of DNG profiles. DNG profiles can be used in  Adobe® Imaging solutions including Lightroom®, Photoshop®, Photoshop® Elements, and Camera Raw (ACR). As well, its gray patches can be used for gray/white balance, to correct color casts or bad lighting. Here is a list of software that perform such tasks:

DNG Camera profiles

ColorChecker Passport (X-Rite) Use the ColorChecker Passport Camera Calibration Software to create custom DNG profiles. The software is available in two forms: as a standalone software or as an Adobe Lightroom plugin. This free software, available from the ColorChecker Passport  page, can be used with any Standard or Mini ColorChecker. From the same page, you can also download the DNG Profile Manager, a utility tool for managing your camera profiles.

ICC Profiles

inCamera (PictoColor) (camera, scanner) inCamera is a Photoshop plug-in designed for the sole function of generating ICC profiles for digital cameras and scanners from captured images of color charts. These ICC profiles can be applied to similar images taken in the same lighting conditions. Apart from the standard ColorChecker, it supports most commercial charts, such as the ColorChecker SG, a chart which comprises 140 semi- gloss patches which should, and does, provide better quality profiles, and industry standard IT8 targets. i1Profiler (X-Rite) (printer only, NO camera profiles) i1Profiler is a component of the i1Publish solutions.

White/Gray Balance (using a single neutral patch)

Adobe Camera Raw (ACR) (integrated with Adobe software) AfterShot Pro, the new name of Bibble, purchased by Corel Capture One, or C1 (Phase One) Lightroom (Adobe) Photoshop and Photoshop Elements (Adobe) Photos for OS X (Apple) White/Gray Balance using a dedicated white balancing tool is a simple method of correcting an image colors using a single neutral patch, one of the ColorChecker neutral patches for instance (!), which is supported by all of the programs listed above. Once color balance is achieved by using the target in a first image, the settings can be saved and applied on subsequent images taken in the same conditions. Note: The white patch of the ColorChecker is never recommended for white balance since it is not considered neutral enough. Instead, the third patch from the left, in the bottom row, is often suggested. However, there is no scientific or technical reason why a very neutral and diffused white target cannot be used for such a task (see this tutorial for more info)!

Other

ACR Calibrator, a free Photoshop script to automate the process of calibrating Adobe Camera Raw (ACR), by Thomas Fors If you own Photoshop and have a digital camera that outputs RAW files, you should try ACR Calibrator, which automates the process of using the standard 24 patches ColorChecker for calibrating RAW file via the Adobe Camera Raw plug-in (known as ACR). Picture Window Pro (Digital Light & Color) custom color transformation Picture Window Pro has a "Match Reference" feature which generates a color transformation based on the captured image of the ColorChecker chart. Once the transform is generated, you can rapidly correct images taken in the same lighting conditions. This feature is very similar to inCamera except that the correction is a command instead of an ICC profile. Picture Window Pro has many other useful tools and features for the digital photographer, such as perspective correction, selective color control, a complete set of mask tools, and 48 bit (3 x 16 bit) files support.

Discontinued software

Aperture (Apple): White/Gray balance Replaced by Photos, a semi-pro application streamlined for sharing and mobile devices. See this MacWorld article mentioning that development stopped and this MacRumors article confirming that the software was removed from the Mac App Store. Bibble (Bibble Labs, purchased by Corel, replaced by AfterShot Pro): White/Gray balance Capture Studio, for Kodak Professionnal DCS Digital Cameras (Kodak): ICC profile The Capture Studio software from Kodak is a Mac only product dedicated to the RAW file format used in the Professional DCS Pro Back line of  cameras (which is now discontinued but support is still available). One of its features is ICC profile generation from a ColorChecker. This free software can be downloaded from the DCS Cameras support page (click on Digital Cameras and Backs, then on Firmware/Software downloads, or click this link). MonacoPROFILER Platinum (Monaco Systems, purchased by X-Rite): ICC profile (camera, scanner, monitor, printer) MonacoPROFILER Platinum  can generate an input device ICC profile from many chart types, including the standard ColorChecker chart, even if some spec sheet do not mention this chart explicitly. Of course, the software can do much more, and it includes many tools to create high quality profiles for monitors and color output devices (printers and presses), but its price is in consequence. ProfileMaker (X-Rite): ProfileMaker was available in many different packages, and bundled or not with an Eye-One Pro or an i1iSis; only three of these packages are shown here. o ProfileMaker 5 Platinum: ICC profile (camera, scanner, monitor, printer) o ProfileMaker 5 PhotoStudio Pro: ICC profile (camera, monitor, printer) o ProfileMaker 5 Publish: ICC profile (scanner, monitor, printer) ProfileMaker is a very complete high-end measuring and profiling package. The Digital Camera module, available in the PhotoStudio bundle, can generate an ICC profile for a camera using the ColorChecker as well as the ColorChecker SG or the older ColorChecker DC (at least in version 5.0.5b and 5.0.8). Please note that the ColorChecker is supported even if this is not mentioned in the current Web page; however, this is confirmed in the Profile Maker 5 multi-lingual Quick Start Guide (see for instance page 29 in the English section). For a lower cost solution that combined software with the measuring instrument, there was the i1XTreme bundle, which could make profiles from the ColorChecker SG (purchased separately), but not the ColorChecker. With all the above software, you generate your color correction transform or profile by incorporating the ColorChecker card in your photographed scene, and by analyzing the chart patches in the resulting image (this also works for calibrating a scanner). They are best used when you can manually adjust and freeze your digital camera white balance. If your digital camera does not enable you to control white balance, then you may still obtain good results if the lighting AND the color content of your scenes do not vary too much. These tools can also be used with traditional film if the lighting conditions do not change during the photo session (the white balance does not change in a traditional film, it is just not balanced!). Of course, you need a new profile each time you change the lighting conditions, and some may feel that generating and managing many ICC profiles--lighting does vary a lot--could become cumbersome. Having a set of transforms, as with Picture Window Pro or an automated script, such as ACR Calibrator, are two alternatives to eliminate that burden. Of course you do not absolutely need a ColorChecker to calibrate RAW files, as you can manually tweak the RAW import parameters. This method, however, can be more demanding than the ones presented above, and it is important to note that RAW files are NOT standardized, with each digital camera company proposing its own variant, some of them proprietary (see the OpenRAW web site for more info on this potential problem). Adobe has proposed the "public" Digital Negative (DNG) archive format to address the issue. In any case, using the ColorChecker within your images, as part of the RAW file manipulation process, or with any other file format, will definitely provide helpful visual feedback. Even with all these tools, there are pictures which remain difficult to correct; Cal McCamy's picture shown in Page-1 of the ColorChecker pages is one such case. Taken under fluorescent lighting and saved under a JPG format, it cannot be corrected with a simple click. The old adage which says that it is preferable to place a filter on the lens than to correct the picture afterwards applies here; however, such filters are not universal to all types of fluorescent lamps (and there are many) and are simply not part of most photographers' accessory bag.

Using the chart to analyze your camera's performance

If you want to check the accuracy of a ColorChecker image, and thus the accuracy of a camera profile or of the correction procedure applied to an image, you can use PatchTool's Extract Target from Image tool, designed specifically to extract the average  of target patches in full size photographic images. This tool can accommodate targets of any size in almost any position, and can easily be configured to extract a ColorChecker. The supported image formats are TIFF RGB (8 bit and 16 bit), and JPG. Embedded profiles are recognized and automatically extracted. To measure your camera's color quality, noise, and tonal response, you can use the Colorcheck module of the Imatest program offered by Norman Koren. The Colorcheck program uses images of the ColorChecker chart to perform its analysis. Use this program to check how the automatic white balance feature of your camera is working. The other Imatest modules are dedicated to measuring the sharpness and gray response using other types of targets (you can print some of the targets). This program is becoming a reference for digital camera analysis, as can be seen on the imaging-resource.com site. Note: If you are interested in photography in general, and in its technical aspects in particular, you have to go on Norman's namesake site, www.normankoren.com, where you will find some of his images, which can be purchased, and a tremendous amount of free technical info on digital photography.

The problem with the ColorChecker Digital SG

The ColorChecker SG is a chart dedicated to digital photography. It has a Semi-Gloss finish with highly saturated colors. On the chart Web page we read that its features include "24 patches from original ColorChecker," and the corresponding patches are laid out on the SG chart in the same configuration as in the standard ColorChecker. Many would assume, by the layout and these words, that they are the same, but this is not the case since the semi-gloss finish introduces measurable differences. ColorChecker SG data Spectral data for charts manufactured BEFORE November 2014; the origin is unknown but is likely from GretagMacbeth: Digital ColorChecker SG.txt L*a*b* D50 data for charts manufactured BEFORE November 2014: ColorCheckerSG_Before_Nov2014.txt L*a*b* D50 data for charts manufactured AFTER (or during) November 2014: ColorCheckerSG_After_Nov2014.txt Using reference data from X-Rite, there is an average DeltaE*ab difference of about 7 (3.7 in CIEDE2000) between the standard ColorChecker and the corresponding patches of the ColorChecker SG. This has been confirmed with measurements on two charts (the measured values of these two charts are very close to one another however, which is good since it shows manufacturing consistency). We see the same statistics when comparing the two charts BEFORE or AFTER the November 2014 formulations changes. Because of this, it is not recommended to use the average spectral data, the RGB and L*a*b* values, and the images of the standard ColorChecker for comparison with the "equivalent" patches of the ColorChecker Digital SG chart.
BabelColor ®

THE COLORCHECKER PAGES (3/3)

Click to go to a section of interest:

Page-1: Attention ! Warning ! Important ! Read-me ! A brief presentation  ColorChecker charts formats / pictures New color specifications since November 2014  (New section - 2016/01) Where to buy? Page-2: ColorChecker data (RGB coordinates, spectral data, Excel tables) (Updated - 2016/01) Visual comparisons (BEFORE Nov. 2014 vs AFTER Nov. 2014) (New section - 2016/01) Visual comparisons (individual charts vs average) ColorChecker images (RGB and L*a*b*; 8/16-bit) (Updated - 2016/01) Do you want to provide some data? Page-3 (this page): Using the chart to auto-correct images or make ICC/DNG profiles Using the chart to analyze your camera's performance The problem with the ColorChecker SG (Updated - 2016/01)

Using the chart to auto-correct images

or make ICC/DNG profiles

Because the ColorChecker patches cover a relatively large color gamut, not with a lot of samples mind you, one could think of using it to generate a correction profile, and the chart can effectively be used to generate an ICC profile or a DNG camera profile. It could be argued that making an ICC profile with a ColorChecker is foolish, but it is certainly better than no calibration at all. For many years it was possible to make scanner, monitor, printer and camera profiles using the ColorChecker with ProfileMaker Pro and MonacoPROFILER; unfortunately, it is only possible to make such profiles for printers in i1Profiler, the software that has replaced both ProfileMaker and MonacoPROFILER. Nowadays, the ColorChecker is more targeted ;-) for the creation of DNG profiles. DNG profiles can be used in  Adobe® Imaging solutions including Lightroom®, Photoshop®, Photoshop® Elements, and Camera Raw (ACR). As well, its gray patches can be used for gray/white balance, to correct color casts or bad lighting. Here is a list of software that perform such tasks:

DNG Camera profiles

ColorChecker Passport (X-Rite) Use the ColorChecker Passport Camera Calibration Software to create custom DNG profiles. The software is available in two forms: as a standalone software or as an Adobe Lightroom plugin. This free software, available from the ColorChecker Passport  page, can be used with any Standard or Mini ColorChecker. From the same page, you can also download the DNG Profile Manager, a utility tool for managing your camera profiles.

ICC Profiles

inCamera (PictoColor) (camera, scanner) inCamera is a Photoshop plug-in designed for the sole function of generating ICC profiles for digital cameras and scanners from captured images of color charts. These ICC profiles can be applied to similar images taken in the same lighting conditions. Apart from the standard ColorChecker, it supports most commercial charts, such as the ColorChecker SG, a chart which comprises 140 semi-gloss patches which should, and does, provide better quality profiles, and industry standard IT8 targets. i1Profiler (X-Rite) (printer only, NO camera profiles) i1Profiler is a component of the i1Publish solutions.

White/Gray Balance (using a single

neutral patch)

Adobe Camera Raw (ACR) (integrated with Adobe software) AfterShot Pro, the new name of Bibble, purchased by Corel Capture One, or C1 (Phase One) Lightroom (Adobe) Photoshop and Photoshop Elements (Adobe) Photos for OS X (Apple) White/Gray Balance using a dedicated white balancing tool is a simple method of correcting an image colors using a single neutral patch, one of the ColorChecker neutral patches for instance (!), which is supported by all of the programs listed above. Once color balance is achieved by using the target in a first image, the settings can be saved and applied on subsequent images taken in the same conditions. Note: The white patch of the ColorChecker is never recommended for white balance since it is not considered neutral enough. Instead, the third patch from the left, in the bottom row, is often suggested. However, there is no scientific or technical reason why a very neutral and diffused white target cannot be used for such a task (see this tutorial for more info)!

Other

ACR Calibrator, a free Photoshop script to automate the process of calibrating Adobe Camera Raw (ACR), by Thomas Fors If you own Photoshop and have a digital camera that outputs RAW files, you should try ACR Calibrator, which automates the process of using the standard 24 patches ColorChecker for calibrating RAW file via the Adobe Camera Raw plug-in (known as ACR). Picture Window Pro (Digital Light & Color) custom color transformation Picture Window Pro has a "Match Reference" feature which generates a color transformation based on the captured image of the ColorChecker chart. Once the transform is generated, you can rapidly correct images taken in the same lighting conditions. This feature is very similar to inCamera except that the correction is a command instead of an ICC profile. Picture Window Pro has many other useful tools and features for the digital photographer, such as perspective correction, selective color control, a complete set of mask tools, and 48 bit (3 x 16 bit) files support.

Discontinued software

Aperture (Apple): White/Gray balance Replaced by Photos, a semi-pro application streamlined for sharing and mobile devices. See this MacWorld article mentioning that development stopped and this MacRumors article confirming that the software was removed from the Mac App Store. Bibble (Bibble Labs, purchased by Corel, replaced by AfterShot Pro): White/Gray balance Capture Studio, for Kodak Professionnal DCS Digital Cameras (Kodak): ICC profile The Capture Studio software from Kodak is a Mac only product dedicated to the RAW file format used in the Professional DCS Pro Back line of  cameras (which is now discontinued but support is still available). One of its features is ICC profile generation from a ColorChecker. This free software can be downloaded from the DCS Cameras support page (click on Digital Cameras and Backs, then on Firmware/Software downloads, or click this link). MonacoPROFILER Platinum (Monaco Systems, purchased by X-Rite): ICC profile (camera, scanner, monitor, printer) MonacoPROFILER Platinum  can generate an input device ICC profile from many chart types, including the standard ColorChecker chart, even if some spec sheet do not mention this chart explicitly. Of course, the software can do much more, and it includes many tools to create high quality profiles for monitors and color output devices (printers and presses), but its price is in consequence. ProfileMaker (X-Rite): ProfileMaker was available in many different packages, and bundled or not with an Eye-One Pro or an i1iSis; only three of these packages are shown here. o ProfileMaker 5 Platinum: ICC profile (camera, scanner, monitor, printer) o ProfileMaker 5 PhotoStudio Pro: ICC profile  (camera, monitor, printer) o ProfileMaker 5 Publish: ICC profile (scanner, monitor, printer) ProfileMaker is a very complete high-end measuring and profiling package. The Digital Camera module, available in the PhotoStudio bundle, can generate an ICC profile for a camera using the ColorChecker as well as the ColorChecker SG or the older ColorChecker DC (at least in version 5.0.5b and 5.0.8). Please note that the ColorChecker is supported even if this is not mentioned in the current Web page; however, this is confirmed in the Profile Maker 5 multi-lingual Quick Start Guide (see for instance page 29 in the English section). For a lower cost solution that combined software with the measuring instrument, there was the i1XTreme  bundle, which could make profiles from the ColorChecker SG (purchased separately), but not the ColorChecker. With all the above software, you generate your color correction transform or profile by incorporating the ColorChecker card in your photographed scene, and by analyzing the chart patches in the resulting image (this also works for calibrating a scanner). They are best used when you can manually adjust and freeze your digital camera white balance. If your digital camera does not enable you to control white balance, then you may still obtain good results if the lighting AND the color content of your scenes do not vary too much. These tools can also be used with traditional film if the lighting conditions do not change during the photo session (the white balance does not change in a traditional film, it is just not balanced!). Of course, you need a new profile each time you change the lighting conditions, and some may feel that generating and managing many ICC profiles--lighting does vary a lot--could become cumbersome. Having a set of transforms, as with Picture Window Pro or an automated script, such as ACR Calibrator, are two alternatives to eliminate that burden. Of course you do not absolutely need a ColorChecker to calibrate RAW files, as you can manually tweak the RAW import parameters. This method, however, can be more demanding than the ones presented above, and it is important to note that RAW files are NOT standardized, with each digital camera company proposing its own variant, some of them proprietary (see the OpenRAW  web site for more info on this potential problem). Adobe  has proposed the "public" Digital Negative (DNG) archive format to address the issue. In any case, using the ColorChecker within your images, as part of the RAW file manipulation process, or with any other file format, will definitely provide helpful visual feedback. Even with all these tools, there are pictures which remain difficult to correct; Cal McCamy's picture shown in Page-1 of the ColorChecker pages is one such case. Taken under fluorescent lighting and saved under a JPG format, it cannot be corrected with a simple click. The old adage which says that it is preferable to place a filter on the lens than to correct the picture afterwards applies here; however, such filters are not universal to all types of fluorescent lamps (and there are many) and are simply not part of most photographers' accessory bag.

Using the chart to analyze your

camera's performance

If you want to check the accuracy of a ColorChecker image, and thus the accuracy of a camera profile or of the correction procedure applied to an image, you can use PatchTool's Extract Target from Image tool, designed specifically to extract the average of target patches in full size photographic images. This tool can accommodate targets of any size in almost any position, and can easily be configured to extract a ColorChecker. The supported image formats are TIFF RGB (8 bit and 16 bit), and JPG. Embedded profiles are recognized and automatically extracted. To measure your camera's color quality, noise, and tonal response, you can use the Colorcheck module of the Imatest program offered by Norman Koren. The Colorcheck program uses images of the ColorChecker chart to perform its analysis. Use this program to check how the automatic white balance feature of your camera is working. The other Imatest modules are dedicated to measuring the sharpness and gray response using other types of targets (you can print some of the targets). This program is becoming a reference for digital camera analysis, as can be seen on the imaging-resource.com site. Note: If you are interested in photography in general, and in its technical aspects in particular, you have to go on Norman's namesake site, www.normankoren.com, where you will find some of his images, which can be purchased, and a tremendous amount of free technical info on digital photography.

The problem with the ColorChecker

Digital SG

The ColorChecker SG is a chart dedicated to digital photography. It has a Semi-Gloss finish with highly saturated colors. On the chart Web page we read that its features include "24 patches from original ColorChecker," and the corresponding patches are laid out on the SG chart in the same configuration as in the standard ColorChecker. Many would assume, by the layout and these words, that they are the same, but this is not the case since the semi-gloss finish introduces measurable differences. ColorChecker SG data Spectral data for charts manufactured BEFORE November 2014; the origin is unknown but is likely from GretagMacbeth: Digital ColorChecker SG.txt L*a*b* D50 data for charts manufactured BEFORE November 2014: ColorCheckerSG_Before_Nov2014.txt L*a*b* D50 data for charts manufactured AFTER (or during) November 2014: ColorCheckerSG_After_Nov2014.txt Using reference data from X-Rite, there is an average DeltaE*ab difference of about 7 (3.7 in CIEDE2000) between the standard ColorChecker and the corresponding patches of the ColorChecker SG. This has been confirmed with measurements on two charts (the measured values of these two charts are very close to one another however, which is good since it shows manufacturing consistency). We see the same statistics when comparing the two charts BEFORE or AFTER the November 2014 formulations changes. Because of this, it is not recommended to use the average spectral data, the RGB and L*a*b* values, and the images of the standard ColorChecker for comparison with the "equivalent" patches of the ColorChecker Digital SG chart.