Testing the ColorReader EZ, LS170 and LS173 with Behr Paint Swatches

The most professional approach to testing a colorimeter is probably using Pantone swatches.  But, my budget wouldn't allow that.  So, I took the poor man's approach.

I made the assumption that paint manufacturers have to pay very close attention to make sure their color swatches precisely match there published color values.  Fortunately, every HomeDepot has  a broad selection of Behr paint swatches and the color values of every one of those swatches is published on Behr.com.

(By the way, matching paint colors is precisely the application for which these colorimeters were designed.)

I gathered several swatches, looked up their color HEX and RGB() values on the we site and began testing with each of my colorimeters.  Pay close attention to the DELTA columns, as they document just how far off the reading are for Red, Green and Blue of each colorimeter. (Click for full size)

 

The first thing that stood out to me is that there is no standard of deviation.  No colorimeter is consistently off by a certain direction by a set amount. That is, none of the colorimeters consistently measure darker or lighter.

But, the tests also verified that the LS173, with the D/8° lighting system is generally the closest match.  The LS170 uses a 45°/0° lighting/capture system.  The first value, 45° indicates that lighting is cast at a 45° angle and the second value indicates the camera takes an image at 0°.

The LS173, on the other hand, uses a sphere diffusing (D) lighting system and captures the image at 8° offset.  this probably helps reduce lighting artifacts from specular surfaces. 

It's important to remember that these professionally printed swatches are smooth and our 3D prints are relatively rough and uneven, even if we use ironing.  So, it is no surprise that the numbers we get with testing never match the published numbers from the filament manufacturers.  The best we can expect is that our colorimeters will provide us with a very, very close match that we can use to find other brands of filaments having a nearly identical profile.