Lab values for Midtone values

[rajkengeri]

If magenta 100% Lab values are L=48 a=74 b= -3 and paper white lab values are L= 95a=0 b=-2 then what could be the midtone lab values?
I need a formula to caluculate midtone values from solid lab and paper lab for 100% TO 0%.

Your valuable suggestions are much appreciated

 

[gordo]

If magenta 100% Lab values are L=48 a=74 b= -3 and paper white lab values are L= 95a=0 b=-2 then what could be the midtone lab values?
I need a formula to caluculate midtone values from solid lab and paper lab for 100% TO 0%.

I doubt such a formula exists. But if it did, it would have to have a factor for the screening being used since that has a significant impact on the resulting color.

best, gordon p

 

[Bret Hesler]

I agree with Gordo. I don't know of a formula for this purpose. However, the numbers you are referencing are straight from the ISO standard. So you can find the theoretical target from common data sets conforming to the same standard, such as Fogra 39 or Gracol 2006, whichever is most applicable to your printing conditions.

For your reference, the midtone magenta values from those data sets are:
Fogra 39 71.23 L 33.64 a -7.3 b
Gracol 2006 70.24 L 35.3 a -6.06 b

Bret

 

[ishantkalkal]

no need to measure

no need to measure

there is no need to measure tone's Lab value.
There is standard only for solid one.
I dont know from where Mr Bret Hesler got the ton's Lab value?

 

[martin.weberg]

I dont know from where Mr Bret Hesler got the ton's Lab value?

He's pretty clear on that:
"theoretical target from common data sets conforming to the same standard, such as Fogra 39 or Gracol 2006"

Martin Weberg