Digital BW, The Print

Hey everyone. I'm wondering if anyone has a random 256 Gray target
file for creating a QTR lin and also if that even works (256 that is).
I guess I can make one with TextEdit but that would take a while . . .

thanks, Walker

256 is likely huge overkill.  Even my 101 steps is.  Happy to email you it
if you want.  You can make your own using a text editor and Colorlab (a free
download from Gretag Macbeth)

From: Walker Blackwell <wblackwell@gmail.com>
Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Date: Tue, 19 Sep 2006 15:39:27 -0000
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Subject: [Digital BW] 256 Gray Random Target for QTR

 
 
 

Hey everyone. I'm wondering if anyone has a random 256 Gray target
file for creating a QTR lin and also if that even works (256 that is).
I guess I can make one with TextEdit but that would take a while . . .

thanks, Walker

 
    



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

Steve,

Do you have a link to Colorlab, I can't find it on the GM downloads page.

Txs,
Mike


On 19/09/06, Steve Kale <stevekale@...> wrote:
>
>    256 is likely huge overkill. Even my 101 steps is. Happy to email you
> it
> if you want. You can make your own using a text editor and Colorlab (a
> free
> download from Gretag Macbeth)
>
> From: Walker Blackwell <wblackwell@... <wblackwell%40gmail.com>>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com<DigitalBlackandWhiteThePrint%40yahoogroups.com>
> >
> Date: Tue, 19 Sep 2006 15:39:27 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com<DigitalBlackandWhiteThePrint%40yahoogroups.com>
> >
> Subject: [Digital BW] 256 Gray Random Target for QTR
>
> Hey everyone. I'm wondering if anyone has a random 256 Gray target
> file for creating a QTR lin and also if that even works (256 that is).
> I guess I can make one with TextEdit but that would take a while . . .
>
> thanks, Walker
>
> [Non-text portions of this message have been removed]
>
> 
>


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

Actually 256 steps might not even work. You'll definitely get some 
noise/random errors in the measurements that might very well be 
larger then the differences in the steps. The QTR linearization 
algorithm expects a monotone series of numbers. Even if the steps 
are not large enough the algoritm can complain, as a experienced 
recently.  

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Steve Kale 
<stevekale@...> wrote:
>
> 256 is likely huge overkill.  Even my 101 steps is.  Happy to 
email you it
> if you want.  You can make your own using a text editor and 
Colorlab (a free
> download from Gretag Macbeth)
> 
> 
> 
> From: Walker Blackwell <wblackwell@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Tue, 19 Sep 2006 15:39:27 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: [Digital BW] 256 Gray Random Target for QTR
> 
>  
>  
>  
> 
> Hey everyone. I'm wondering if anyone has a random 256 Gray target
> file for creating a QTR lin and also if that even works (256 that 
is).
> I guess I can make one with TextEdit but that would take a 
while . . .

> 
> thanks, Walker
> 
>  
>     
> 
> 
> 
> [Non-text portions of this message have been removed]
>

Depending on your goals and methods, the readings _before_ linearization
from so many steps can be helpful to determine if your measured curve is
smooth enough for the linearization to “work”, i.e. the humps and dips are
not very large or abrupt.
Using measure tool with my eye-1 in strip scan mode, the noise is low enough
to resolve 1024 gray patch steps; rather surprising in itself.  That said, I
don’t believe you need large numbers of patches for QTR to linearize well.
I believe Roy is pleased with the 21 patch x 4 reading approach.

Best regards,
John Moody

-----Original Message-----
From: DigitalBlackandWhiteThePrint@yahoogroups.com
[mailto:DigitalBlackandWhiteThePrint@yahoogroups.com]On Behalf Of horstenj
Sent: Wednesday, September 20, 2006 12:38 PM
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: Re: [Digital BW] 256 Gray Random Target for QTR

Actually 256 steps might not even work. You'll definitely get some
noise/random errors in the measurements that might very well be
larger then the differences in the steps. The QTR linearization
algorithm expects a monotone series of numbers. Even if the steps
are not large enough the algoritm can complain, as a experienced
recently.



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

http://www.gretagmacbeth.com/products_profilemaker5_sw

Take a look there.




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