update due to more experience using a tried-and-true tri-color ( green purple copper );
best results: 3 sided model;
ok results: round (such as a globe)
worst result: even-numbered-sided models
hit-and-miss: irregular shapes; recently i experienced a case where the copper was almost completely teased out in favor of greens and purple (still looked quite nice);
on another occasiion using tri-color (a different 3 color combo) one of the colors , gold i believe, was teased out ;
looking at cross sections of the filaments show uniform thirds of each co-extrusion color;
must be one interesting algorithm that determines which color where and how to transition from one color to another (surprisingly those transitions seem to look ok, no messy banding)
adding more observations:
using a Green\Purple\Copper i have had very good success and the resultant products look really nice:
this is over a number of models and a number of spools;
using a Gold\Copper\Blue i have had very little success; the reason being color-banding as shown in the following image:
what is a bit odd is that all the filament (PLA) in question came from the same E-Vendor so i presume the same chinese manufacturer,
despite the 2nd variant noted above starting with “Gold”, most often i could never coax any real amount of gold color out in any attempt over various models over various spools other than the banding shown in the image (and that is only on the one “side”);
the first variant proportions about evenly over the Green\Purple\Copper as a visual inspection of a cross section of the filament shows;
so, again, it is a bit of a crap-shoot on the multi-colors; since i usually got little-to-no-gold color on the variant that says “Gold…” , it appears the order of the colors doesnt mean much more than marketing
have encountered a new fundamental difference in how these dual/tri/quad/+ color extrusions are available to us;
the first variation is true co-extrusion where ,in the example of a dual color, the two colors are extruded in parallel, so a cross section shows roughly 50 % of each color;
the second variation is a simple serial color-add; whereby the first say 10 % of the spool is one color, then the 2nd 10 % or so is another color, and so on;
the photos below show that difference the 5 color, rainbow on the left spool prints 10 % puke green then 10 % yellow, 10 % copperish, etc as the layers are piled on eeach other;
the other spool green/blue can easily print a 4-sided object with 2 sides green and the other 2 sides blue (quite stiking really) , each layer has a green and blue “side”
the next image is the first two spools flipped over, you can clearly see the green v blue sides;
here is an example of the 5 color rainbow color-layering:
multi-colors continue to escape pattern recognition;
recently i experienced differing results from the same g-code, same printer WITHIN the same spool;
can that be explained any other way than 'spool manufacturing inconsistencies ’ ?
i will try to post photos of other errata regarding multi-color;
suffice it to say that sometimes the colors are banded horizontally and sometimes along ‘faces’ ( front,back,sides) and sometimes inexplicable color artifacts are produced;
seems it prudent to print small scale samples as previews ( and even that presumes that the color schemes will maintain across scaling);
but i have to say that sometimes those multi-colors can produce some awesome results ( and sometimes duds)
this is all PLA and almost always Silk PLA;