Colorimeter Targets, Scanning Setup and LS173 Scanning Tests

Before beginning the scanning tests, the specifications for the targets had to be determined and the targets printed.  Two color printing is required to print the target information; but, we also wanted to iron the top layer of the scanning target.  If you try to iron a 3D printed part having text of a contrasting color it's a mess.  So, we came up with a two-part system, using our existing Marswork ID tags, used with the Marswork Quick-Swap Spools and filament management system.

Two-Part Scanning Targets

Note how the ID tags simply clip into the scanning target for correct identification.  The targets are printed with 100% Rectilinear infill and the insert portion is ironed using a setting of  60mm for speed and 30% for flow.

To ensure that the capture is done at the correct angle and precise positioning, a special holder for each colorimeter was 3D printed that included a stand for the smartphone.

LS173 Colorimeter Stand

 

The stand has a slot for the target that places it at the same exact spot for each scan.  Both the LS173 and LS170 can be rotated in 90 degree angles as necessary.

The same tests that were performed using the LS170 were completed using the LS173.  In both cases, repeated scans were consistent and within a point or so.  In this regard, the LS170, is just as consistent as the LS173.  At half the price, it's probably the best value.  Although, the screen of the LS173 is very useful.

Here are the results of the LS173 color captures. (Click for full size)

The lighting system of the LS173 is diffused and it is the camera that is offset at 8 degrees.  Based on what I see here, the rotations made little or no difference and there is actually little difference between the ironed and un-ironed surfaces.  Generally the difference is less than 2 points!  But, with black, the difference between the published value and the tested values was significantly greater than that of the LS150 by almost 20 points.  With White, the two colorimeters were in agreement.  

None of the colorimeters in the price range with which I am working deal with 'sheen'  as a separately tested quality.  I have a feeling that 'sheen' plays a factor in testing 3D printed parts.

Now that we know, for sure, that we are not going to be able to match ANY published color spec with an affordable colorimeter, we need to determine if and how the information they do give us can help in our work.  We also want to explore whether HEX & RGB() or LAB values are where we should put our focus.