High ink coverage

[rich apollo]

The big problem wit the method is that it is so difficult to see TIC/TAC values in PS with only the pipette/spot measurement rather than area (which you get by converting to RGB/LAB and using gamut warning)

If you go LAB, you may want to convert your image to 16 bit before you start the conversion (and finish up with reducing to 8 bit when done)

Lukas,
Alwan has a plug-in for Photoshop that shows the TICTAC (heh, heh, I like that). Also, TGLC recently rolled out a freebie for that purpose.

Why do you advise to go 16-bit in Lab. If the file has been 8-bit the damage is done, or am I missing something?

 

[Lukas Engqvist]

dynamic range problem

dynamic range problem

Plugg ins are great, but not all people have/ can afford them. Usually the people who design and have no knowledge of TIC/TAC are the ones who send images. Or look at those promopictures that artists agents or marketing departments send out with 360+ ink and mo profile. What I would wish for is that just as we have the gamut warning there would be the same visual when exceeding the ink limit defined in the working or destination space. There are ways to figure it out but the tools should be easy to use, especially as long as people are told to work in CMYK because it is safer.

LAB is such a big space. Remember that the 8.bits represent the whole Lab working space. If you look at your image in Lab you will see that you are not using the whole dynamic range of Lab. so infact even if you have 8 bits mabe you will use 5 or 6 of them.
So your 8-bits will be translated to 5-bits and that means bad maths. If you go to 16 bits you have the redundancy to not loose more information than necessary.
Here are histograms from one image in RGB and Lab, if both are 8 bit they both have the same number of POSSIBLE colours. The RGB uses almost all possible levels in all channels. Lab is not even coming close to using half the possible colours.
RGB histogram LAB histograms