I recently made a profile for Howard Linen by Neenah. I profiled it through a Creo Spire workflow to a Xerox 6060. Even though the paper is meant for double sided printing the fibers of the paper are different on both sides. This causes the toner to lay down differently on each side. This affects color. A couple of notes in case you are not acostomed to profiling through Creo. You have to build a new calibration for your media. then when you send a CMYK profiling testchart through the RIP make sure you send it through a “Direct” pathway. This will bypass any color management – even though there is a choice for ICC profile. Once the profile is built you have to import it back into the RIP. This is not an issue if you have a .icc extension. I taught a course for X-Rite and Creo about a year and half ago all about this and wonder how manyare actually building profiles. John Gilbert would know.
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This is a screen capture of X-Rite’s i1 Match Software. I used my i1 Pro Spectrophotometer to build a calibration and profile for the new 24″ iMac. The default white point was right at 6500 Kelvin and the resultant calibration yielded a perfect 120.0 cd/m2. This is rare. Sometime you get lucky. Other iMac’s I have calibrated don’t give me the same results – that’s not necessarily bad – except one of the best ways to get multiple displays to look similar is to have similar luminance say +/- 2 candelas.
It’s easy to be overwhelmed with thoughts about color – especially if your responsible for color. Art Directors, Designers, Photographers, Commercial Printers, Pre-Press Professionals, all think about color all day. It’s overwhelming and at the same time easy to be complacent. Are you really color critical? When was the last time you stretched your knowledge? Do you know about PANTONE’s new Goe Color and Plus Systems? Do you even know why you are calibrating your monitor? Can you produce a decent in-house proof? What I am trying to stress here is that it’s important to think about color – technically – and keep up with current technological trends. It’s important to stretch your knowledge base and take that class or attend that seminar. The best brands are crazy about precision color reproduction and print quality. The competitive landscape is only going to get more critical as time goes on.
Do you wonder why the photos you print don’t match how they appear on screen? Learn how to color manage your system from capture to print in this short, intensive workshop. From basics of digital color, discover how to use a color management system including software & hardware. Topics include: limitations of color gamuts, color settings, calibration and profiling of a LCD display & profiling a media on the supplied photo quality inkjet printers. Prior experience in digital photography & working knowledge of computers & Photoshop CS , CS 2 or 3 required. Bring 5 digital images to 1st class meeting. Note Printing elective for Professional Certificate in Photography. prerequisite: Intermediate Photography in the Digital Age (ART 40440) or equivalent experience. For more info. or to discuss prerequisites, call (858) 964-1051 or ahl@ucsd.edu.
IN-CLASS
Instructor: Marc Aguilera
Section: 079251 Course No. ART-40402
Time/Date: W 6:30-9:30 p.m., Sep. 22-Oct. 27 (6 mtgs.)
Location: Rm. 134, UCSD Extension Complex
Credit: 2 units in Art
Fee: $325 No refunds after: Sep. 27 (da/amn)
No visitors permitted. Early enrollment advised.
- examples from my latest blog post on the hp pro photography blog
results of projector profiling with i1 Pro and i1 Match
Result from projector profiling with i1 Pro and i1 Match
Skin Tones from projector profiling with i1 Pro
This is essential gear for ICC profiling
SWOP is the Specification for Web Offset Publications and more information can be found at swop.org or the idealliance.org. It is the main specification used by press house in the united states.
Have you taken this test? If not you should. I have taken it three times and have never got a perfect score. I once administered this test to a woman at the SIGGRAPH show in San Diego and she scored perfect many times in a row. She was amazing at seeing color difference. You can take the test online but that’s not as much fun. It’s better to take the test in person. The test is used by the government and industries where determining color difference is really important in a particular job function and it has been used for over 40 years. It consists of 4 trays containing 85 caps – your job is to put the colors that space the spectrum in order of transition from one hue to another. The test must be administered under a daylight balanced light booth as pictured here. If you haven’t taken it or you want to see if your employees are color deficient in a particular area I suggest you get the test.
Profiles are a mystery to most users. Even for me the first few years in color management, I had no idea really what was in an ICC profile. Essentially when I learned what was inside a profile it made for easier understanding of how profiles actually work. While this information is not necessary for an ICC workflow it sure helps with comprehending a general framework of how and why an ICC aware workflow does it’s magic.
According to Understanding Color Management by Abhay Sharma, a profile is “a data file describing the color characteristics of an imaging device”. Profiles are made for scanners, digital cameras, displays, and print devices. There are even profiles for “non-devices” such as a color space profile. Profiles usually have an extension of .icc or .icm. Profiles are used to translate color into or out of one color space to another. An example can be sRGB from your digital camera to the default profile for your display. Another way to explain this is to call upon the Adobe® terminology of source to destination color.
Profiles have two main parts: tags and headers. There are many tags to describe different functions a profile has. There is a quality setting tag. Sometimes you need to fix a particular tag in order to troubleshoot your ICC workflow. The ICC (International Color Consortium) regulates the structure and contents of profiles. The header usually contains information about device type, i.e. Epson Scanner, Apple Cinema Display, hp Designjet Printer. The tags are the body of the profile and contain all the working data. Headers are standardized and contain a fixed number of items. Tags are device dependent and the number of tags vary according to class and profiling software. Display profiles have different tags compared to print profiles. Scanner profiles have different tags compared to “non-device” profiles like Adobe RGB. If you run OS X you can double click on a profile and it will oped colorsync and you can view header and tag information. There are also “profile inspector” tools available to view and even edit the contents of a profile available for both Mac and Windows. LUT’s are Look Up Tables and are found in ICC profiles and are used to do image conversions.
CMM Type
One of the headers is the CMM type. CMM is the Color Management Module and is the color engine that does the color conversion on an image. The main role of the CMM is to convert the image data from one color space to another using all of the information contained in the profile. CMM’s come from Apple, Adobe. and Kodak as well as a few others. The Adobe ACE (Adobe Color engine) is cross platform and is the most common CMM used today. Most CMM’s behave the same way however you can test the effect of a CMM by changing it in a profile editor or in an ICC aware application.
Profile Class
The profile class header tells us what type of profile it, such as scanner, monitor, printer, etc. There are seven profile classes : display (mntr), input (scnr), output (prtr), device link (link), color space (spac), abstract (abst), and named color (nmcl). Typically profile class tells the type of tags that will be present in a profile and without it applications will not know what to expect. We can easily expect what a display, input, or output profile is used for. Device link profiles are one profile that links two profiles together. Most Device link profiles are CMYK to CMYK and are used to shortcut a color conversion. Device link profiles are very effective dealing with issues converting from CMYK to CMYK especially in areas like black generation. Color space profiles examples are Generic Lab and Generic XYZ profiles and are used to convert images into or out of a device independent space. Abstract profiles are used for special purposes like storing image edits and finally named color profiles are used to support color information from named color systems like PANTONE.
Data Color Space and PCS
Data Color Space refers to the device color space like RGB or CMYK. PCS refers to Profile Connection Space and is usually XYZ or LAB. Profiles usually but not always work in both directions, from the Data Color Space to the PCS or from the PCS to the Data Color Space. Another way to look at it From RGB to LAB and from LAB to RGB, from CMYK to LAB and from LAB to CMYK. Because printer profiles can both be RGB or CMYK when you look at the Data Color Space header you can tell if the profile is treating the printer as an RGB or CMYK device.
Next post we will focus on Flags, Rendering Intent, PCS Illuminant, and more.
Question from a Color Control Freak:
I’m interested in purchasing a Monitor Calibrator for my Vista OS. Which monitor calibrator would you recommend? Also, how do I know if the monitor calibrator is compatible with my HP 2009m Monitor? I really don’t understand how a monitor calibrator works and how it can alter the monitor colors. Is it interacting with the NVIDIA video card?
A: I like the i1 Display colorimeter by X-Rite at xritephoto.com. A monitor calibrator works by way of software – hardware interaction. The software resets the data table called a LUT (Look Up Table) sent by your video card to your display. When variables are set like Luminance, Gamma, White Point by the software (usually automatically if using an automatic mode or manually in an advanced mode) with the the aid of the colorimeter will “calibrate” your display by altering the LUT to hit the target variables. You will aid this by setting brightness, contrast, and RGB levels on your display (if you have them). After calibration the software then builds an ICC profile that Vista will use in the OS as well as any other ICC aware applications like all of the Adobe® Photoshop™. Go for it – it will make your images look much more real and true to the original intended color values when captured.
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