[Openicc] Printing targets: App or driver ? Profiling RGB or CMYK

[Chris Murphy]

On May 17, 2011, at 7:12 PM, Robert Krawitz wrote:

> On Wed, 18 May 2011 03:09:02 +0200, edmund ronald wrote:
>> I don't think the inter-device repeatability thing is FUD. Epson has a
>> utility called ColorBase .
>> 
>> http://www.epson.co.uk/article/1227894377886;jsessionid*B3F015106553CA9FBDA79254832611.acc2
> 
> But it requires an external device (it specifies a Gretag MacBeth or
> X-Rite color measurement device).  That sounds like it profiles the
> printer.  A very nice convenience indeed, but it doesn't sound like
> special sauce within the printer.

Appears to only use the Epson print driver (nothing else is mentioned), so my take on this product is that it is merely updating/replacement (maybe supplementing?) the calibration tables formed by Epson in the printer - which in turn purportedly are only accessible or used with the Epson OS native print driver. Not even their own HTM has access to this path apparently.

The biggest differences I've seen printer to printer is with the 100% coverage of each colorant. By yanking down, sometimes substantially, on the per channel ink limit, everything else pretty much falls in line. On one printer I may need a 98% standard cyan limit, and another another printer with same lot # paper and ink and firmware it may be 91% - totally different amounts of ink.

Whereas with the RGB Mac OS driver, I get virtually the same L*a*b* value for 0,255,255 on those same two printers. Clearly these are NOT the same colors being tested - but there's still much greater consistency between printers when using the OS native driver from Epson.

Chris Murphy