QTR-Quadtone RIP

--- In QuadtoneRIP@yahoogroups.com, "Paul Roark" <paul.roark@...> 
wrote:
>
> 
> OK, so you have my HPR profile with the ink positions altered to 
match your
> printer setup.  To re-linearize the profile for your system, clear 
the
> values in the Linearization tab and save it with a name that does 
not
> overwrite a previous file. (I leave the sliders in the various 
tabs in their
> default positions.) Then print a 21-step test file with the new 
profile that
> has no linearization data in it.  Read the test print and insert 
the L
> values into the Linearization table.
> 
> Paul
> www.PaulRoark.com
>
Paul 

Thanks for your help.

I copied your qidf file, gave it a new name, modified the data for 
my ink positions and deleted the linearization data.   In order to 
print the step wedge using this file I also copied your original 
quad file and gave it the same name as the qidf file.  Was this 
correct?

I printed the unlinearized step wedge and, after hair dryer blowing, 
had an Lmin of 15.92 (Dmax 1.75)

I inserted the scanned data and `relinearized'.  Lmin was 16.82 
(Dmax 1.73)

The curve was not linear. You can see this from the linearized 
data.  The first column takes the Lmin and Lmax values from the 
second column which are the scanned L values and calculates equal 
steps between these.  These values therefore decreases linearly.  
Plotting, as a line graph, the first column against the second 
column with the L values shows the curve shape, which is far from 
linear.  It looks as though the ink limit had been set to a high 
negative value, but it, and the gamma value were both set at zero.  
The third and fourth columns are the `a, and `b' values.


Equal steps            L                    a                 b
95.63	95.63	0.62	0.46
91.69	91.83	0.67	0.77
87.75	88.35	0.72	1.07
83.81	84.30	0.85	1.34
79.87	80.70	0.91	1.49
75.93	77.78	1.00	1.67
71.99	75.34	1.08	1.71
68.05	72.58	1.12	1.92
64.11	70.54	1.13	2.05
60.17	67.97	1.16	2.21
56.23	65.90	1.21	2.36
52.28	63.85	1.26	2.29
48.34	60.82	1.24	2.58
44.40	57.34	1.23	2.71
40.46	53.85	1.38	2.78
36.52	49.65	1.48	2.76
32.58	44.40	1.51	3.03
28.64	39.28	1.51	2.96
24.70	33.45	1.57	2.93
20.76	26.70	1.46	2.58
16.82	16.82	0.72	1.08


Any ideas as to what I am doing wrong?


Colin