QTR-Quadtone RIP

Hi, 

I've just downloaded the QTR and am still in the profile/experimental stage. (also 
having ink clogs --ouch)

I've just tried the Roark method of using a scanner to read Lab values of the 21 step 
wedge to use with the create ICC.

And I've successfully produced a profile that looks pretty good, with one exception:  
The maximum black on the print is no longer 100%.  The profile appears to map 
100% black to about 90%.  Using the same data to linearize the curve instead works 
without changing the black density, but for some reason, the ICC profile method 
produces a smoother grey ramp, so I'd rather use that method.

In a nutshell, the ICC makes for a nice soft proof (showing ink black and paper white), 
but not such a good print.  Is there a way to get around this, or is the create ICC only 
designed to be a soft proof profile, and not a printing profile?

-Bruce

www.brucealangreene.com

Hi Bruce,

I've been trying to understand how you are getting this result.   The 
only thing
that comes to mind is not using Perceptual Intent and Black Pt Comp.
In general the profiles should work for both soft-proofing and printing 
and map
black to black.

So how are you printing and how do you see this change in the black?

Roy

On Friday, February 24, 2006, at 08:40  PM, smthopr2000 wrote:

> Hi,
>
> I've just downloaded the QTR and am still in the profile/experimental 
> stage. (also
> having ink clogs --ouch)
>
> I've just tried the Roark method of using a scanner to read Lab values 
> of the 21 step
> wedge to use with the create ICC.
>
> And I've successfully produced a profile that looks pretty good, with 
> one exception:
> The maximum black on the print is no longer 100%.  The profile appears 
> to map
> 100% black to about 90%.  Using the same data to linearize the curve 
> instead works
> without changing the black density, but for some reason, the ICC 
> profile method
> produces a smoother grey ramp, so I'd rather use that method.
>
> In a nutshell, the ICC makes for a nice soft proof (showing ink black 
> and paper white),
> but not such a good print.  Is there a way to get around this, or is 
> the create ICC only
> designed to be a soft proof profile, and not a printing profile?
>
> -Bruce
>
> www.brucealangreene.com
>
>
-
Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com

>
> Hi Bruce,
> 
> I've been trying to understand how you are getting this result.   The 
> only thing
> that comes to mind is not using Perceptual Intent and Black Pt Comp.
> In general the profiles should work for both soft-proofing and printing 
> and map
> black to black.
> 
> So how are you printing and how do you see this change in the black?
> 
> Roy
> 

Thanks Roy.


Number 1, I was using relative colormetric intent.
Number 2, BPC was off

I will try again with perceptual intent if I can ever get the printer to print black ink 
again!  Very frustrating.

-bruce

PS. I'm curious. Why does this profile require perceptual intent?  I didn't think that 
relative colormetric remapped the black or white points.

Roy,

I was wondering if you could further elaborate/explain the choice of 
perceptive instead of relative in using the Create-ICC to better 
understand what it does.

Thanks.

Olivier

--- In QuadtoneRIP@yahoogroups.com, Roy Harrington <roy@...> wrote:
>
> Hi Bruce,
> 
> I've been trying to understand how you are getting this result.   The 
> only thing
> that comes to mind is not using Perceptual Intent and Black Pt Comp.
> In general the profiles should work for both soft-proofing and 
printing 

> and map
> black to black.
> 
> So how are you printing and how do you see this change in the black?
> 
> Roy
>

Hi Bruce,

Actually for printing there is only one curve and it has 100%K-to-100%K 
builtin
so I don't think the various intents ought to make a difference.

In soft-proofing however there are many profile conversions happening 
and its
hard to tell from the PS selections where are the mappings go.

So the more I think about it, it sounds like your workflow is 
introducing too many
conversions somewhere.   I think you are somehow printing the Ink Black 
simulation
of the soft-proof but I'm not sure how that could be happening.   Are 
you printing
directly from Photoshop using the Print with Preview screen?  Might you 
be
printing the proof instead of the source file?   Are you printing with 
the QTR driver?
The more you can elaborate your workflow the better.

Roy


On Saturday, February 25, 2006, at 07:58  PM, smthopr2000 wrote:

>
>>
>> Hi Bruce,
>>
>> I've been trying to understand how you are getting this result.   The
>> only thing
>> that comes to mind is not using Perceptual Intent and Black Pt Comp.
>> In general the profiles should work for both soft-proofing and 
>> printing
>> and map
>> black to black.
>>
>> So how are you printing and how do you see this change in the black?
>>
>> Roy
>>
>
> Thanks Roy.
>
>
> Number 1, I was using relative colormetric intent.
> Number 2, BPC was off
>
> I will try again with perceptual intent if I can ever get the printer 
> to print black ink
> again!  Very frustrating.
>
> -bruce
>
> PS. I'm curious. Why does this profile require perceptual intent?  I 
> didn't think that
> relative colormetric remapped the black or white points.
>
-
Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com

(I'm resending with the correct subject - sorry)


Hi Roy,

Here is the data file that I used to make the ICC profile:

Gray      Lab_L

0.00      97

5.00      96

10.00    91

15.00    85

20.00    79

25.00    73

30.00    68

35.00    62

40.00    58

45.00    53

50.00    49

55.00    46

60.00    42

65.00    39

70.00    35

75.00    31

80.00    28

85.00    26

90.00    22

95.00    19

100.00 15

I employed the profile in the Photoshop Print with Preview using 
relative colormetric intent. I tried it both with the BPC on and off.

At first I didn't notice the black was not full black until I looked at 
the black patch of the grayscale next to the black border (the black 
border does not go through the ICC profile and always is sent as 
100%black) and noticed that the black patch was not as dark as the 
border. So it seems that 100% black after going through the ICC profile 
is output as 95% instead. Not obvious at first, but it takes some of 
the punch out of the print.

When the same data are used to Linearize the curve instead, the 
100%black is preserved.

-bruce

> Message: 12
>    Date: Sun, 26 Feb 2006 12:27:13 -0800
>    From: Roy Harrington <roy@...>
> Subject: Re: Re: Create ICC and maximum black in print
>
> Hi Bruce,
>
> Actually for printing there is only one curve and it has 100%K-to-100%K
> builtin
> so I don't think the various intents ought to make a difference.
>
> In soft-proofing however there are many profile conversions happening
> and its
> hard to tell from the PS selections where are the mappings go.
>
> So the more I think about it, it sounds like your workflow is
> introducing too many
> conversions somewhere.   I think you are somehow printing the Ink Black
> simulation
> of the soft-proof but I'm not sure how that could be happening.   Are
> you printing
> directly from Photoshop using the Print with Preview screen?  Might you
> be
> printing the proof instead of the source file?   Are you printing with
> the QTR driver?
> The more you can elaborate your workflow the better.
>
> Roy
>

Hi Bruce,

Well that's the weirdest problem recently.   I cut the data out of your 
post and
tried it.  Sure enough --  the 100 line is not used.   I eventually 
looked at the data
byte for byte and it turns out there are invisible characters in all 
lines except the
100 line.  So in the 100 line the data columns don't line up correctly.

Anyway, I just got rid of the special characters and it works fine.

Roy

This is the corrected data.  It looks the same.
Gray  Lab_L
0.00  97
5.00  96
10.00  91
15.00  85
20.00  79
25.00  73
30.00  68
35.00  62
40.00  58
45.00  53
50.00  49
55.00  46
60.00  42
65.00  39
70.00  35
75.00  31
80.00  28
85.00  26
90.00  22
95.00  19
100.00 15


On Monday, February 27, 2006, at 11:29  AM, bruce greene wrote:

> Gray      Lab_L
>
> 0.00      97
>
> 5.00      96
>
> 10.00    91
>
> 15.00    85
>
> 20.00    79
>
> 25.00    73
>
> 30.00    68
>
> 35.00    62
>
> 40.00    58
>
> 45.00    53
>
> 50.00    49
>
> 55.00    46
>
> 60.00    42
>
> 65.00    39
>
> 70.00    35
>
> 75.00    31
>
> 80.00    28
>
> 85.00    26
>
> 90.00    22
>
> 95.00    19
>
> 100.00 15
>
-
Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com