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  1. J

    Interesting study from Ryerson University on expanded color gamut printing.

    Hmmm... I looked at the sessions for the FTA Fall Conference next month. I don't see a lot about EG. But there used to be a lot! Try this. Here is a quote from one of my old blogposts: In 2013 Mark Mazur conducted a survey that estimated that 10% to 20% of printers in the flexo world were using...
  2. J

    Interesting study from Ryerson University on expanded color gamut printing.

    I was one of the advisors on the study. I hope I can clear up some of the questions / misperceptions. First, I appreciate the interest in the topic! We had much discussion about the tests before we began. One of the decisions was to keep the focus narrow so we could get results out quickly. We...
  3. J

    Spot Colors and Spectrophotometer

    The spot color measurement metric that Techkon has added to their spectro is one that has been officially defined in a brand new standard, ISO 20654. The standard is based on work done by the SCHMOO group. (I am proud to say that I gave the group its name: Spot Color Halftone Measurement...
  4. J

    GRACoL2006 M2 Numbers

    I have looked at actual data, comparing M2 and M1 measurements. From this, I can say that a solid black or yellow effectively blocks all OBAs. I suspect that black just blocks everything and that yellow largely blocks the emitted fluorescence. Solid cyan and solid magenta inks block about half...
  5. J

    Color Muse

    From his Facebook posts, I think Widmer is having way too much fun travelling to want to do anything serious again! Lots of gorgeous pics from all over the world.
  6. J

    Color Muse

    Somehow, I got the CIELAB values directly from the app. I don't have the unit with me at the unit, so I can't try it now. I recall that maybe there was a compare color mode... which computes a deltaE from a reference that you type in?
  7. J

    Color Muse

    I was comparing measurements to a Spectrolino. Admittedly not the most accurate device, but I have compared this unit against an eXact, a Spectrodens, and a 939, and the differences on white/gray/black samples was below 1.0 DE.
  8. J

    Color Muse

    The aperture of the Color Muse is about 1 cm and the Nix is about 1.4 cm. The Color Muse and the Nix both use a sensor developed in Germany by the company MazeT. The sensor is small and cheap. The tristimulus sensor leads to one limitation for both devices. Even if the sensor were an...
  9. J

    Review of inexpensive digital microscopes

    Digital microscopes don't need to be expensive. I have posted part two of my reviews of some digital microscopes that can be had for under $100. http://johnthemathguy.blogspot.com/2017/01/comparison-of-inexpensive-digital_12.html
  10. J

    RGB can NOT describe colour

    You're welcome. I learned everything I know from Danny! :p
  11. J

    RGB can NOT describe colour

    Ahhh.. Dr. Irwin Corey... I need to watch some YouTube videos of that guy! I don't think the app can help, unfortunately. You're looking for something pretty specific.
  12. J

    RGB can NOT describe colour

    LOL ... Like I said, it's involved. My approach would be to assume the mathematical model that a unit change in each of the pigments would cause some corresponding change in L*, a*, and b*. For 5 inks, this would give 15 coefficients. Under this assumption, this can be solved through multiple...
  13. J

    RGB can NOT describe colour

    Yes, I know how to do this. It's not very simple math, though. I would not ever want to try it by hand. It's rather involved, but Excel could be taught how to do it.
  14. J

    RGB can NOT describe colour

    LMS color space - Wikipedia, the free encyclopedia
  15. J

    RGB can NOT describe colour

    D Ink Man, If I understand this correctly, you are looking for a quick and dirty kind of ink formulator. If I can paraphrase, to make sure I am understanding correctly... You have created a bunch of similar recipes (same set of pigments, different concentrations) that come close to your target...
  16. J

    RGB can NOT describe colour

    Schnitzel, The quick answer is "no". In the mid 90's we had such a system, based on an RGB camera. We put around 20 man years into making the system stable at measuring light. It was a good densitometer with somewhere around 1,000 of them in the field. We realized that we needed to provide...
  17. J

    RGB can NOT describe colour

    The camera does not absolutely need to have XYZ filters. Any linear combination of the XYZ filters can be directly translated into XYZ filters without introducing error. The LMS filters are an example of such a linear combination. These are named after "long", "medium" and "short", and they...
  18. J

    RGB can NOT describe colour

    Yup... my eyes have different spectral response than the camera that I used... and different from every RGB sensor that I have seen. That is the crux of the problem. (I'm guessing that your eyes are probably different from the camera's as well.)
  19. J

    ink density and conductivity measurement tool

    Chevalier, What sold you on the Techkon?
  20. J

    RGB can NOT describe colour

    Stephen, please feel free to put comments wherever it's convenient. I get comments on the blog, on LinkedIn, Facebook, and Twitter, wherever people see my links. Often I get private messages. If there are some interesting comments, I share them in a followup blog post.

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