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Digital BW, The Print

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Do I need a Spectrophotometer to calibrate?

Do I need a Spectrophotometer to calibrate?

2007-05-19 by Pat Turner

Hello everyone,

Is it necessary to use a spectrophotometer to get accurate results? I
have a calibrated 23" monitor and I'm using UT7 inks along with QTR on
my Epson 2200. So far I've just used the canned profiles that came
along with QTR, but my prints don't exactly match the monitor. In an
effort to calibrate the ICC profiles, I'm finding that I may need the
aforementioned piece of hardware. It's pricey so I'm trying to avoid
it. Is there another way? I've read (and tried) Paul Roark's method of
using a flatbed scanner, but to no avail .... I get an error message
that ends with "The Lab values are not in order. Cannot make a profile."

It's probably something I'm doing, but .... is there another way to
match print to screen that I'm not using? Or is there a manual
somewhere that lays this all out a little more clearly. I admit that
I'm a little confused by all the options. What I'm trying to do (I
guess) is linearize the canned profiles to something that matches my
monitor a little more accurately.

Any tips?

Pat

RE: [Digital BW] Do I need a Spectrophotometer to calibrate?

2007-05-20 by Paul Roark

>.error message that ends with "The Lab values are not in order. Cannot make
a profile."

 

This happens if there is posterization.  That is, a step where the Lab value
should be going down, in fact, it goes up.  The system needs at least some
slope on the input curve.

 

Read your test strips from paper white to black.  Note the order of the
template text for in http://www.paulroark.com/BW-Info/Making_B-W_ICCs.htm .
The column on the left is the gray %, as noted on the bottom of the test
strips.  Then Lab L will go from that paper white ov about 97 to the dmax of
about 16 on good matte paper.

 

If the prints have a good ramp - nice smooth, even steps - then you can make
a custom dot gain curve (see
http://www.paulroark.com/BW-Info/Monitor-Profiling.htm ) or a curves
adjustment layer to match the view to the print.  I still use layers to
match views at times.  That is just a manual way of doing it.  

 

Paul

www.PaulRoark.com <http://www.paulroark.com/>  

 

 

 

 

  _____  
Show quoted textHide quoted text
From: DigitalBlackandWhiteThePrint@yahoogroups.com
[mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Pat
Turner
Sent: Saturday, May 19, 2007 1:16 PM
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: [Digital BW] Do I need a Spectrophotometer to calibrate?

 

Hello everyone,

Is it necessary to use a spectrophotometer to get accurate results? I
have a calibrated 23" monitor and I'm using UT7 inks along with QTR on
my Epson 2200. So far I've just used the canned profiles that came
along with QTR, but my prints don't exactly match the monitor. In an
effort to calibrate the ICC profiles, I'm finding that I may need the
aforementioned piece of hardware. It's pricey so I'm trying to avoid
it. Is there another way? I've read (and tried) Paul Roark's method of
using a flatbed scanner, but to no avail .... I get an error message
that ends with "The Lab values are not in order. Cannot make a profile."

It's probably something I'm doing, but .... is there another way to
match print to screen that I'm not using? Or is there a manual
somewhere that lays this all out a little more clearly. I admit that
I'm a little confused by all the options. What I'm trying to do (I
guess) is linearize the canned profiles to something that matches my
monitor a little more accurately.

Any tips?

Pat

 



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

Re: [Digital BW] Do I need a Spectrophotometer to calibrate?

2007-05-20 by Pat Turner

Thanks for the response Paul,

I've included the data I used to try and create the ICC. I believe
it's in the correct order. 

Gray    Lab_L
0.00    99
5.00    95
10.00   91
15.00   87
20.00   83
25.00   79
30.00   74
35.00   70
40.00   66
45.00   63
50.00   59
60.00   51
65.00   47
70.00   43
75.00   38
80.00   35
85.00   31
90.00   26
95.00   20   
100.00  14

RE: [Digital BW] Do I need a Spectrophotometer to calibrate?

2007-05-20 by Paul Roark

Are you using a tab between the Gray and Lab_L columns?  If not, see if it
works that way. 

 

Paul

www.PaulRoark.com <http://www.paulroark.com/>  

 

 

 

  _____  
Show quoted textHide quoted text
From: DigitalBlackandWhiteThePrint@yahoogroups.com
[mailto:DigitalBlackandWhiteThePrint@yahoogroups.com] On Behalf Of Pat
Turner
Sent: Sunday, May 20, 2007 7:10 AM
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Subject: Re: [Digital BW] Do I need a Spectrophotometer to calibrate?

 

Thanks for the response Paul,

I've included the data I used to try and create the ICC. I believe
it's in the correct order. 

Gray Lab_L
0.00 99
5.00 95
10.00 91
15.00 87
20.00 83
25.00 79
30.00 74
35.00 70
40.00 66
45.00 63
50.00 59
60.00 51
65.00 47
70.00 43
75.00 38
80.00 35
85.00 31
90.00 26
95.00 20 
100.00 14

 



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

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