[Lcms-user] Black preservation

[Larry Tseng]

Hello list,   I find the preserve black feature to be very helpful in cmyk to cmyk conversions when k-only images, text and graphics should remain k-only after the conversion. Lcms does this nicely, and with proper k-only tone compensation as well. Unfortunately, "colorful" cmyk text and images can experience large color shifts, enough to render the feature unusable, and very problematic in situations where both k-only and colorful cmyk material are both present in the source.   I am wondering whether the idea of "clean-blacks", as implemented in devicelink profiles created by ColorThink Pro, Link-o-lator, and GretagMacBeth, isn't the better way to go. Here, cmyk converts in the usual way except for the special case of k, where c=m=y=0%, which is subjected to a k-only to k-only transform.   Regards,   Larry Tseng