Hi Richard,
thanks for your input. You pointed me to some important aspects of QTR linearization. I believe your sketched value array represents the grey curve linearization, not the main linearization curve. The interesting thing about the grey curve array field is that it can take more than 21 or 51 value pairs - it should take 100 value pairs, to be precise. With that it is possible to manipulate very exactly the grey curve. I transformed the LAB L values from SpyderPrint to grey curve values and did that way the whole linearization. Especially in the lights this seems to have some benefit since you can exactly determine for each % density input a corresponding correction factor. I applied this for the first 11 values (0% to 10%) then in increments of 10%.
I still have to understand what the relationship between the linearization curve and the grey curve is. Does the linearization curve "rule" the other curves - i.e. is it applied to the grey and toner curves?
Regards,
Amin