We are asked quite often what the method is for determining the color placement in our sets of color pencils. The larger Faber-Castell sets are of particular interest, in which there may be many shades of a particular color, but each similar may not be placed side by side. 

"Is there logic, scientific or artistic rational for separating what are seemingly similar colors in these large sets?" 

The answer...

We chose this order of placement for the pencils because we want to create a harmonious order that is appealing to the eye. We always start with light colors from the left and end with dark colors on the right. Furthermore, we take care that warm and cold colors are shown one after another. 

Having this in mind, it is quite easy to understand why some yellowish or greenish tones are not placed next to all other yellows and greens. There are some colors that contain green/yellow/red (e.g. ochre) but have a higher proportion of brown. For this reason they belong to the color category "brown" and not "yellow" etc. If we would place, for example, the ochre between the dark chrome yellow and the cadmium orange, one can immediately see that the transition of the colors from yellow to orange is not harmonious anymore.