Is 'natural' colored filament equally brittle compared to white filament? I've read that white filament is a lot more brittle, because the pigment percentage is close to 50 %, e.g. black filament it's only around 8 %. I was therefore wondering if 'natural' colored filament, which has a somewhat ivory appearance, is also brittle like white filament.
Maybe the color name is a marketing lie or maybe it is really natural colored and there has slim to no pigment in the filament. Making it therefore less brittle. Since the color is closer to white than black I would guess the first one but I would love to be certain.
No
Natural colored filament has no pigments added, the ivory off-white color is the natural color of the mixture in the filament.
Also note, those white filaments can have much less than 50 % volume percentage of pigment, depending on the exact hue of white. The starkest cold whites might make that, warmer white can work with a lesser amount. Pigments are part of the filler materials.  The other fillers make the filament behave in the designed way and can make up a considerable amount of the filament. Usually, less than 40 % are fillers compared to the PLA.