Comparing 3D Filaments with the LS173 Colorimeter.

Both the Linshang LS-170 and the LS-173 have USB ports for charging.  But, only the LS-173 can also link to a computer via USB for color capture.  This was the primary reason for making that additional purchase.  While it turns out that the Windows app designed to work with the LS-173 doesn't report the complete range of color information as does the smartphone app.  It does perform one vital function that I have found to be very useful.

The Windows application is called Color Haze Meter.   The 'Haze' part of the name indicates that the software is designed to work with a variety of products including the LS155 Color Haze Meter for measuring and comparing the clarity of transparent materials and liquids.  I believe it is used in brewing industries.

Here is the screen layout of the Color Haze Meter software:  (Click to see full size)

Color Haze Meter Software for the Linshang LS173

 

TOP PORTION OF THE SCREEN 

The software expects to see two different scans before it renders a verdict on the outcome of the comparison.  In our case we wanted to compare the identically identified colors from Bambu Labs and Marswork.  In every case the published HEX values between the comparisons were identical.  The question we wanted to know is just how closely they actually match.  We first scanned the Bambu Labs and then scanned the comparable Marswork filament.

Since the primary goal of this application is to compare two different samples the color information presented is limited as LAB color values.  Each row contains the LAB color information for the "Standard" that was scanned and the comparison "Sample".  

As each pair is sampled, the last column in the Comparison Measurement spreadsheet provides a helpful comment.  In the case of the comparison of the Bambu Labs Mistletoe Green vs the Markswork Mistletoe Green it reports that the differences in the Lightness (L*) values was "Normal" and the Marswork sample had a "Slight Red" bias and a "Slight Blue" bias.

But, the most important notification is in the bottom cell where it says, "PASS", meaning that the two samples are within acceptable color difference limits.

In fact, in every case, using the default industry standard delta Thresholds of 5.0 every single comparison PASSED, meaning from a visual standpoint they were functionally equivalent.

BOTTOM PORTION OF THE SCREEN

The Color Haze Software allows us to scan batches of samples and with each two scan cycle it stores the result in a line on the lower half of the screen.  In this case, we made 5 different comparisons and changed the name of each line to indicate the color tested.

But, here is the really nice part. With just one button click we can export the results to an Excel spreadsheet where we can format the presentation any way we want!  (Click to see full size)

Formatted Excel Export from the Color Haze Meter Software

 

I find this to be incredibly helpful information.  For it tells me that should a certain color not be available from one vendor, there is another vendor's product that is virtually an exact match!

ABOUT THOSE SLIGHT DIFFERENCES 

Quite frankly, if I hold one of my test swatches for Bambu Labs Basic Jade White up against the side of the LS173, it's clear that the 3D filament is not precisely HEX #FFFFFF or RGB(255,255,255).  The plastic of the injected case for the LS173 is slightly brighter.  The question is, "Why?"

Actually, the published value is the "TARGET" used by the manufacturers to determine the colorants to be used to make the final product.   Asking AI about white filament revealed that raw 3D printer filament is naturally translucent.  So, Titanium Oxide is used to make it as close to the "White" target as possible.  But, from batch to batch there can be minor fluctuations even among the same brand.  That's normal.

This concept of a published HEX color being a "TARGET" is true of all colors.  What is important is the "Perceived Color" of the final product.  As we examine these results comparing LS173 scans of like colors from Bambu Labs and Marswork, we see some differing values.  (Click to see full size)

LS173 Comparisons: Bambu Labs / Marswork

But, if we look very closely at the far right it is clear that the "Perceived Colors" are virtually identical for the vast majority of users.  Can there be perceived differences over time?  Conceivably, but in theory, those same minor differences could show up in the very same product line, since colors are newly mixed with every new batch.

 

Coming up with a Colorimeter Strategy for 3D Prints

 I used the Behr swatches as a staring place, because paint comparison is exactly the application the manufacturers had in mind when designing their products.  Paint swatches are professionally printed uniformly on smooth surfaces.  Thus, they provide a good starting place with which to compare the performance of the colorimeters I own.

3D prints, on the other hand, are NOT uniform surfaces.  They are, by the very nature of the way they are produced, corrugated in form, reflecting light in lines of brightness and darkness in a photo.  Here, for instance, is the bottom of our test print we are using for our colorimeter work.

Bottom of 3D Print Sample

 

The corrugated nature of the 3D print is plain to see,  And, it's easy to imagine that the very nature of the surface would make at least SOME difference in our colorimeter readings.

We can minimize this effect by smoothing, to some extend, by "Ironing" the top surfaces of our test objects.  Here is the top of our test object that has been 'Ironed" to increase smoothness.

"Ironed" top of 3D Print Sample

 

While not as perfect as the surfaces of our Behr color samples, it is at least somewhat improved.  Given the differences in surface quality I decide to test whether these two surfaces return measurably different results.

The LS170 was selected for this test because of the lighting/capture system it uses. 

The LS170 relies on a 45°/0° capture system, meaning the lighting hits the target at an angle of  45° and the camera capture directly from above at 0°.  

 I wondered if the lighting angle might reflect differently in one orientation as apposed to another due to the artifacts in the 3D print.  So, I also decided to see if rotating the LS170 90 had any affect on the outcome.

This meant each sample would be tested 4 times.  The top would be sampled twice, at 0° and 90° as would be the bottom.  The LS170 lends itself to this reorientation due to it's square shape. 

The differences (Delta) between the published Bambu color specs were then calculated for each test. 

THE RESULTS

Five different Bambu Labs filaments were selected for testing.  The goal was to compare the results between the ironed top and raw bottom of the print sample.  Each of these were tested twice by rotating the LS170 by 90°. The differences (Delta) between the published Bambu color specs were then calculated for each test.  (Click on image for the full size)

While these results haven't been fully analyzed, it seems clear that the ironed top surface generally produces smaller differences than the bottom counterparts.  What is obviously clear is that LS170 ALWAYS returns a darker shade than the specs of the target color.  It's not enormous, in most cases; but, visible in the samples.

I was actually quite surprised that rotating the LS170 didn't seem to make all that much difference in the results. 

We plan to run the same test using the LS173, which relies on a different lighting/capture system, before scanning all of our current inventory.  I suspect our Delta values will be much smaller overall.  But, I do NOT expect to ever match the target specs.  These best we might be able to do is come up with a uniform offset that can applied.  More importantly, as the library of color samples continues to grow on FilamentColors.xyz, we will be building our own library of colors for entering into their search engine.  And, we will have the tools to locate a closely matching color should we need to search for one.

UPDATE 

After my initial posting of this article, I realized that it was a major oversight not to have included the color "Basic Black: in my tests.  So, here it is:

Why this is an important inclusion is that it gives us the bandwith of the colorimeter.  By sight we can see that Bambu Black is as black as one could expect.  Yet it does NOT register as uniform zeros across Red, Green and Blue by the colorimeter.  The light source of the colorimeter is bright enough, and the surface reflective enough,  to register almost 50 units above zeros across the spectrum.

When we combine this with the readings of around 20 points LOWER for white than we might expect, it's clear that, at least when measuring rough surface plastics, the bandwidth of the colorimeter is less than the full spectrum.  This is common in all digital photography.  Professional photographers use a histogram to pull blacks down and whites up to achieve the proper contrast.  

It doesn't matter all that much if our goal is simply to compare a specific color of one brand against another as long as we use the same colorimeter using samples printed in the very same way. 

 

 

The Mystery Color that started the quest!

Before moving on to a post regarding my tests of the three colorimeters I have purchased, I thought I might provide some background about how this interest in colorimeters got started.

It all began with this project, a set of stackable DVD cases in 8 different colors.  Each if these cases holds one DVD of a movie of interest to the person for which they were created.  It is their goal to use a spinner having the same set of eight colors to randomly select a movie for family viewing.

DVD Case Stack

 

Unfortunately, I did not know the FULL scope of the project when the DVD cases were printed.  And, of course, each of these colors is vitally important to the person for whom they were created.  The colors form a set and both cases and spinner sections must match exactly.

The problem I faced is that one of the colors (in the black box), which was printed quite a while ago, was a complete mystery to me.  Try as I might, I had yet to find the filament that was used.  It is not a Bambu Labs color and in the past, recreating colors was just not all that important to me.

But, once I became aware that color CAN be and IS vitally important to others, I decided to try to find the color using a colorimeter... finally leading to the purchase of three colorimeters using 3 different lighting systems.  The goal was to find a starting point from which to search the FilamentColors.XYZ filament color library.

Here is the color information as captured by the LS173 colorimeter and entered onto the search form of FilamentColors.xyz web site..

FilamentColors.xyz Search

While the library is not all inclusive, it did return some likely candidates.

Filament Match Candidates

 

Of these, the only brand I had purchased in the past was Anycubic. And, I had, in fact, purchased a green.  

Notice that the search return also gives us a 'Delta" of the differences between the search values and the values as tested by FilamentColors.  

VISUAL PERCEPTION 

I have come to realize that the values vary according the the instruments used for testing.   

That is because each system is trying to determine the colors in terms of the way humans perceive colors.  And, that process is skewed by the lighting and lens systems used.  None of my colorimeters return the same values.  And, this will be the topic of my next blog entry.

Even so, there is real value in a combining our own testing with a colorimeter along with using those values to search the FilamentColors library.

UPDATE

The hunt is still on!  I found some Anycubic Green. printed an ID Tag and compared that to the mystery color.   It's close.  But, not a match!  So, the search goes on.  In the meantime, I am having a great deal of fun discovering all sorts of new information that I find profoundly interesting.

Color Management: Indispensible to Filament Management

As I have delved deeper into the benefits of the Marswork Filament Management system, some glaring oversights in our past workflow priorities have become undeniably clear.  One major oversight was in not paying closer attention to the exact colors of the filaments we used in the past.

That's understandable, in that for the bulk of the time we have been using 3D printing, the primary available options were monochrome printers.   So, putting a lot of effort into the minute details of the color of filament we were using didn't make much sense.  Even in those cases where I had two color printers, the color needs were so basic that simply choosing red over green for a project was good enough.

But, when Bambu Labs and other manufacturers opened the door to multi-head (4+) printing and slicers improved the prospects of full-spectrum printing, things got a lot more critical when it came to paying attention to color.  More importantly, the bulk of my printing is now producing objects for others.  And they are a lot more particular about the color combinations used in their projects.

The Marwork ID Tag system opened my eyes to the need for knowing and documenting every color used in every project for future reference.  The fact that both Bambu Labs and Marswork publish the HEX values for all of their filaments gave me to right place to start building this documentation.

In the process, however, I found that past lapses created some important gaps in my being able to locate the filaments used in projects prior to our full reliance on Bambu Labs and Marswork.  In trying to fill these gaps, I began to create a spreadsheet of all of the HEX values, and their converted RGB values, for our filaments.  For those filaments made by manufacturers that published their HEX values it appeared to be an easy task.  And, fortunately, low cost colorimeters were available on Amazon to use for those few filaments we owned with unknown HEX values.

COLORIMETER #1 - DataColor ColorReader EZ

I can't afford a $2,200 Pantone Spectocolorimeter, so I opted to go with a distinctly less costly option.  My first choice was the ColorData ColorRead EZ.

DataColor ColorReader EZ and IPhone App

The ColorReader EZ is a bluetooth device that captures color information and reports it via a smartphone App.  The device and app are extremely easy to use. The app reports both LAB and RGB color values.

Scanning each 3D printed ID tag brought me to some interesting conclusions.  Not a single scan matched that of the published HEX color value for any tested filament.  I wish I could say the comparative values were close; but, they were not.  This was a bit of a puzzle; but, it wasn't even the beginning of my learning curve when it comes to this topic.

I wasn't entirely surprised because I assumed that the manufacturers COULD afford that $2,200 option.  And, it's generally true that you get what you pay for.  I simply added 3 more columns to my spreadsheet, to include my tested RGB values.  But, just to satisfy my curiosity I decided to try a different low-cost colorimeter.

COLORIMETER #2 -  Linshang LS170

The Linshang LS170 colorimeter is available on Amazon from a variety of vendors.  It was a little less expensive than the ColorReader EZ. 

Linshang LS170 device and Smartphone App

Just like the ColorReadEZ, the Linshang LS170 is a bluetooth device that connects to a smartphone for capturing and reporting.  Again, both device and app are easy to use.  

Once again, the results of my scans did not exactly match the manufacturer's published RGB values. But, the first thing I noticed was that repeatability of results among  multiple readings were considerably more consistent. And, I felt the LS170 was easier to place over the ID tag targets precisely where i wanted to check.

RESULTS WILL VARY

The website Filamentcolors.xyz is an extremely valuable resource.  The test unit they use to document the color of filament is more expensive than the ones I have used so far,  Interestingly enough, but not too surprising,it is rare for their tested value to exactly equal the manufacturer's published Hex value. That is not a significant issue if we only rely on one or the other source when comparing color values and looking for matches.  So, I am building a dual database of Bambu Labs filaments we use that lists both the manufacture's published value and that from FilamentColors.xyz.  More on that in a later post.

IT IS MOSTLY "TEAL"....

Back to my current Linshang LS170...  Like my first colorimeter, it reports both LAB and RGB values.  And, it was while using the LS170 that I began to feel that, perhaps, while convenient, HEX and RGB values might not be the most valuable way to document colors for my purposes.  This realization became crystalized as I was trying to find a match for a filament we had previously extensively used but no longer had in our inventory.

One of my favorite movie lines is from "The Princess Bride"... "He's not dead, he is only MOSTLY dead." 

We have to view color names in that same vein.  Any given filament described as "TEAL" is only MOSTLY Teal.  It's somewhere in the neighborhood. That's true even among different product lines from the same company.

The color I was hoping to match was either a Cyan or Teal and I suspected that it was a Polymaker filament.  Polymaker manufactures many different lines of excellent quality fillament.  Searching my my Amazon purchase history I  found I had purchased Teal in both Polymax and Polysonic versions.  But, both of the lines come on cardboard spools and I'm trying to move entirely to refills to be used with the Marswork Quick-Swap spools.

Fortunately, Polymaker does release one line of filament in refill format.  Polychroma.  And, it was available in  Polymaker Teal, the same description of the Teal in both Polysonic and Polymax lines.  I purchased the Polychroma.

I was astonished that the Polychroma Polymax Teal was NOT a match!

So I dug a little further and came up with the information in this chart.  (Click to see at 100%)

"Teal" Hex Color Values for Various Polymaker PLA Lines

 

This was immediately helpful in explaining why the newly purchased Teal from Polymker did not match what I had previously used.  As you can see, there is considerable color variations in the "TEAL" family from this one manufacturer. In an effort to see close matches, I then ordered this list in HEX value order.  (Click to see at 100%) 

Polymaker "Teal" list Sorted by HEX value

But, HEX sort left me unsatisfied that this would be the most helpful in comparing filament colors. So, I then decided to sort on the Lab "Lightness" value.  This was the result.   (Click to see at 100%) 

Polymaker "Teal" list sorted by LAB Lightness Value

 

With this one sort, it dawned on me that I definitely needed to include the LAB value of all of our filaments (or prospective filaments).  To make this capture process quicker and easier, I have ordered a Digcreat LS173 Colorimeter (manufactured by Linshang)  that will connect directly to a computer via USB as well as smartphone.  

Digcreat LS173 USB & Bluetooth Colorimeter

 

The LS173 should help speed up the progress because it has the capability to export in Excel format.  While I am not certain, I hope that it will help me quickly capture a series of ID tags and export as a group.  I will let you know how it actually performs as soon as I can give it a workout. 

I will lso let you know how this entire quest goes.  I'm convinced that the documentation is well worth the effort over the long term for those of us that find ourselves printing repeated products for others or retail.

This is only the beginning of this journey.  So, if you are interested in better color management of your filaments, please check back to this blog.