Hi, I am thinking ahead to colour blending/mixing.


I am thinking ahead to colour blending/mixing. Aside from the difficulties of actually mixing multiple filament streams (which I am happy to leave to the likes of @Sanjay_Mortimer1 ​, @Joshua_Rowleyhttp://et.al.) I have a question relating to the actual colours used.

I know that traditional press printing uses CYMK on white paper. For 3D printing you would have add White as a separate colour requiring 5 extruders.

Would it be possible to use the 3 artistic primary colours (Red, Yellow and Blue) and White? It seems to me that this would permit the use of just 4 extruders and the basic colours might be more readily available.

Artistic types, am I missing something?

Without K/black, you’ll never get grey tones of any kind, just a range of pastel tones, or, at the darkest, brown, but never true black.
Whereas on paper (Inkjet) you can add as much of the prime colors to a spot to darken it to practically black, the mixable color range of FFF 3D printing is limited by how much pigment/colorant the input filament contains.

OK, that makes sense. I would imagine that black/grey/white would have to be handled carefully and possibly separately because small amounts of black and white could have a big effect on the mixed colour.

Yes, I think white and black would need to be included.

Re the RGB v.s. CMY - see this article http://www.worqx.com/color/color_systems.htm
K is used to save on using 3x coloured inks to create an almost-black as Tom says.

In 3DP you also need the white (because there is no paper) and whilst you are at it, why not add in clear so you can vary alpha!? :slight_smile:

@Joshua_Rowley ​ OK, so ideally we could be looking at a 6 channel mixing head? That should keep you busy for a while and with all those channels “snaking” around, may I suggest you call this one Medusa.

I saw a printer with 16 heads once! It must have weight 100 pounds! I have sketches of a 6 head Extruder but it’s for color switching. Mixing is tough and the patent minefield is growing.