Digital BW, The Print

When I measured the 24 patches of a GretagMacbeth ColorChecker with both the devices you mention (which includes a six step gray ramp) and compare the Lab values from each, the average difference is less than one delta-e, meaning visually indistinguishable. So I would not expect it to be the device that's the issue, unless one of the two devices is faulty. One other possible issue is the difference between "machine linear" (gamma 1.0) and "human linear" (closer  to gamma 2.2).

C. David Tobie
Global Product Technology Manager
Imaging Color Solutions
Datacolor inc. 
cdtobie@...
www.datacolor.com

On Apr 5, 2013, at 8:10 PM, "mccarvill" <mccarvill@...> wrote:

> Has anyone compared these two devices in terms of accuracy (specifically luminance data)? A printing house I'm considering going with for large prints made two test prints for me that included a 21-step grayscale image. Neither was close to linear, according to my Spyder3 Print Spectro. When I pointed this out, they claimed my device wasn't accurate and that their profiles (made using the Eye One Pro) are linear. But they won't measure my test strips with their Eye One Pro or share their linearizing data. Obviously, I'm skeptical, but I'm curious if there's data available on how these devices compare.
> 
> Mark 
> 
> 


[Non-text portions of this message have been removed]