Re: [Lcms-user] CIELab and lightness

[<ma...@li...>]

Hi Armindo,

> I would like to lighter or darker a CIELab value.
> 
> for this I only modify the L value, for example to darker it by 20%  I do
> Lr:= L x 0.8
> to lighter it by 20% I do Lr:= L x 1.20;  if L>100 then L:=100;
> 
> but sometimes I give very strange result (darker a yellow came red...)
> 
> Am I wrong in my formula?

No... L should control the luma, and leave hue alone. Your
formula seems ok. 

Could you please tell me wich value and profiles does give
such values? And... this happens only with lcms or PhotoShop
also does it?

Regards,
Marti.

>