Roberto Michelena wrote:
I've just realized that 2% in the profiling targets is basically useless... because it won't be able to make a difference in the profile itself, due to the grid.
That's not strictly true. Argyll does attempt to derive per device curves, and these will distort the spacing of the grid as measured by device values. There are limits to what the per device curves will do, and they probably won't be as effective as a per device channel calibration system, but none the less, the capability is there. Normally these device channel curves are inverted in creating the B2A table.
Certainly with the calibration system that I'm most familiar with (from the Colorbus RIP product), we used 2% patches in our test wedges.
> Now, if the profile were to be used for proofing (device->PCS) or with > a CMM that does on the fly table reversal (instead of using > pcs->device it just reverses device->PCS) such as argyll, then it's > better. But still, to have the 2% patches work in profiling, you'd > need to build a profile with 41 gridpoints (which would give you 2.5% > resolution on device channels), which most profiling packages don't > (argyll does, right?).
There are ways of doing this (using -q), although there is a very large price paid in terms of profile creation time.
Graeme Gill.
