It is no doubt about the fact, that recommendations on use and application of dyes, chemicals, machines, etc. have a very attractive generic character. That has been used for such a long time, that today it seams that specific processes have no reason to be created and used.

The goal of optimization of dyeing processes is to develop dyeing cycles in which each minute is responsible for progress in the dyeing mechanism, not accepting periods in which "nothing happens".

The fact that a given process merits the name of "generic process" accepts that using such kind of process for all possible dyeing recipes (Colors) it has to present periods in which "nothing happens". Such periods will be in different places depending of the recipe used.

As a rule, a generic process can only be used successfully if the process is based on the use of migration supporting auxiliaries. But the use of such auxiliaries  is basically one of the biggest reasons to met in danger the Color reproducibility, specially changing the liquor ratio (partially loaded dyeing machines as consequence of the market requirements).

In my contacts with the dyeing industry I have always faced one of the following situations:

1. We have no problems concerning levelness, our main trouble is the Color reproducibility.
2. We have not problems with the Color reproducibility, but we are always running in troubles concerning levelness.

The behavior of dyes  belonging to the same range is far away of to be uniform. One of the biggest factors influencing the kinetic behavior is the rate of diffusion. And the rate of diffusion is first at all depending of the molecular volume and of the way how the substitutes are placed, also different from chromophore to chromophore. If we try to use generic processes, we have to deal with migration based processes. But this kind of dyeing systems tends to decrease the probability of Color reproducibility (see assessment 1). Additionally it is always a risk to accept the generic process for new Colors resp. recipe, what leads to achieve low values of Right First Time for new Colors. The problem is that the market ask for quick response by preparing new Colors, what suffers from the need of corrections if the dyeing conditions at the first lot are not well predefined (to achieve a good "Just in Time" is depending from the accuracy of the "Right First Time")

Choosing the way 2, means to accept and implement that at least several dyeing cycles have to be implemented or in the bast case, it has to be accepted, that our structure of data concerning dyeing cycles has to allow to allocate one cycle to each recipe, if necessary. With the actual possibilities of the computer technology, that presents no more a difficulty. We can also speak of "generic processes with well established criteria for each group". Than can be also realized with an rational grouping of dyeing cycles. The need remain always to predict the dyeing cycle for new Colors resp. recipes, in order to check:

• Either an existent dyeing cycle can be used
• A new dyeing cycle group has to be created

 Due to the fact that the migration capacity of dyeing systems decrease reducing the liquor ratio, it is evident that for short liquor dyeing cycles the strategy of controlled adsorption presents undoubted advantages.

Migration can be taken in consideration in the case the equilibrium of dye distribution fiber / bath will be displaced to bath, p.e. increasing the solubility of the dye (lost of yeld) or increasing the liquor ratio.

Adopting the strategy of controlled adsorption, 2 facts have to be taken in consideration:

• The kinetic of dye adsorption change very strongly moving liquor ratio to low values
• The First-Strike increase also with low values of liquor ration

In order to take advantage of the excellent Color yeld and, consequently, of the good Color reproducibility, the dyeing cycle has to be some more adjusted to each recipe as in the case of migration systems. The big error is to adopt dyeing processes - able to be used in long liquor ratio - in short liquor ratio and no follow the way of specific dyeing cycles based on controlled adsorption.

I can mention my papers mentioned in the Bibliography part: # 115, 118, 120, 129, 134, 135, 137, 141, 142, 152, 155, 157 and 158.

I am convinced that the lake of success and the aversion arised again low liquor ratio (typically THIES) comes from the non observation of these basic facts. Perhaps has been also some lake of confidence studying and using dyeing cycles based on controlled adsorption and adjusted to each dyeing recipe.