Recent content by JohnTheMathGuy

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...

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...

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...

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...

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.

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?

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.

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...

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

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

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.

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...

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.

LMS color space - Wikipedia, the free encyclopedia

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...