It is interesting to compare these two brands since they have so many similarities. Both have a range of 120 colors. For both, three of them are gold, silver and bronze/copper (Pablo/Polychromos).
In large I would say that they perform similar to each other. They both have some colors that are very smooth and creamy and some that are a bit harder (depending on the pigment). Some few colors in the Pablo range have a bit of a waxy feeling to them.
A large difference is the shape of the pencil. Pablo has a hexagon shape and Polychromos are round. I know that a round pencil can be a bit irritating for some people since it has a tendency to roll away, and Polychromos that has a thick varnish on their pencils that is shinny and slippery do roll around. However, it isn’t a huge problem, put a bit of a felt under or keep them in a jar and that problem is solved.
Pablo has a little more greys then Polychromos. And they also have a lot of different grey hues. In Polychromos you get few different hues but a lot of different values of them (they have six warm grey and six cool grey). The warm grey are a close match to Pablos “beige” colors. Polychromos has some other colors using the same principle, as Phthalo (both blue and green) that comes in three values, from light to dark. So if you need help in finding colors that blend good together Polychromos gives you an easy recipe.
They both have about the same range and quantity of pinks and reddish browns that are useful for light skin tones. The Polychromos have them even named “flesh” but the “dark flesh” is really not so much a flesh color as it is a pink color.
The Pablos have a little more earth colors. Both have a lot of olive greens. But Polychromos has a green that looks a lot like what terra verte usually looks like (they also called it Earth green) which is a bit bluer and toned down color. Pablo does not have anything like that. Also Polychromos has a “Pompeian red” that Pablo does not have.
Polychromos has a lot more red and pink colors then Pablo, almost twice as many, but I do not feel that mean so much because the reds are very close to each other in hue, saturation and value. So far Pablo has more earth tones and Polychromos more vibrant colors, but when it comes to turquoise colors, Polychromos really lacking, while Pablo has a large range (even though some colors are a bit to look alike, like “light green” and “turquoise green”).
Complement each other
If you have a set of Faber-Castell Polychromos and only want some colors from Pablo to complement to that, I would recommend following colors: Apricot, olive brown, cocoa and brownish beige (cocoa are darker version of the brownish beige), brownish orange (close to caput mortuum, but has more white), light lemon yellow or pale yellow (colder yellow then the Polychromos Cream), salmon, aubergine, night blue, jade green (Polychromos don´t have anything close), turquoise green or light green, spring green or lime green.
If you have the Caran d’ache Pablo and want to complement with some Polychromos, I would recommend following: indian red, Pompeian red, middle carmine red, Dark red, pink carmine, light magenta, fuchsia, dark indigo, leaf green, permanent green, chrome oxide green (a dark natural green), earth green (terra verte) and grass green.
I appreciate that Polychromos use so many traditional color names, however, some are not used the way I would. Most disturbing is the Alizarin crimson that is far too red in my opinion. Pablo uses less of the traditional pigment names.
84 of the 120 colors that Polychromos offer are lightfast according to CPSA, while only 42 of the 120 colors of Pablo are lightfast (according to CPSA). That is a huge difference.