QTR-Quadtone RIP

I have one printer set up with piezography inks that I use for B&W. 
For colour I am using an R2400 with Image Specialists pigment inks. 
For a bit of fun (or so I thought) I would try and create some curves
for the Ilford Gloss on the R2400.  

I followed the instructions as per usual, using the
UCpk-IlfordSmooth-neut curves as the starting point.  I found that I
needed to use 2880 to avoid some macro banding.  The first set of
linearisation parameters that I derived were not always increasing (or
was that decreasing), and QTR refused to linearise.  

I decided that I had set the ink limit too high (60%), and repeated
the ink separation calculations at 55%.  I honestly thought that this
gave me the right sort of black without overdoing it, and I even
measured this with the i1.  However the curve I produced was rather
lumpy, as per this diagram:

http://www.ferdinand-paris.com/2400_bumpy_curve.gif

I guess I should drop the black limit down to 50%, or are there other
curve parameters that I should be playing with, like the LK & LLK ink
limits or the "Grey Curve" / "Toner Curve x" Tabs?

What does this lumpy curve tell me about what I might have done wrong?
 I've successfully created curves on matte papers before and not had
this problem.

F_P

Ferdinand,

Thanks for the information. Dealing with this is maddening.
With my old Mac  and 1280, and a prior version of QTR
My prints were beautiful. With the new computer and upgraded
version of QTR etc. the curves are fine but there is this damned
micro banding and I'm at a loss.

Regards,
Paul

On Jul 30, 2008, at 8:37 AM, ferdinand_paris wrote:

> I have one printer set up with piezography inks that I use for B&W.
> For colour I am using an R2400 with Image Specialists pigment inks.
> For a bit of fun (or so I thought) I would try and create some curves
> for the Ilford Gloss on the R2400.
>
> I followed the instructions as per usual, using the
> UCpk-IlfordSmooth-neut curves as the starting point.  I found that I
> needed to use 2880 to avoid some macro banding.  The first set of
> linearisation parameters that I derived were not always increasing (or
> was that decreasing), and QTR refused to linearise.
>
> I decided that I had set the ink limit too high (60%), and repeated
> the ink separation calculations at 55%.  I honestly thought that this
> gave me the right sort of black without overdoing it, and I even
> measured this with the i1.  However the curve I produced was rather
> lumpy, as per this diagram:
>
> http://www.ferdinand-paris.com/2400_bumpy_curve.gif
>
> I guess I should drop the black limit down to 50%, or are there other
> curve parameters that I should be playing with, like the LK & LLK ink
> limits or the "Grey Curve" / "Toner Curve x" Tabs?
>
> What does this lumpy curve tell me about what I might have done wrong?
>  I've successfully created curves on matte papers before and not had
> this problem.
>
> F_P
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>

Ferdinand,

It would be more useful if you posted the i1 readings from the 21 step 
wedge for your linerization.

Did you clear out any existing linerization (from the second to last 
tab) before trying to linerize now? Otherwise it is similar to "double 
profiling."

Best,
Michael

--- In QuadtoneRIP@yahoogroups.com, "Michael T. Murphy"
<uriel_bear@...> wrote:
> Did you clear out any existing linerization (from the second to 
> last tab) before trying to linerize now? Otherwise it is similar to
> "double profiling."

The answer to this question is yes, I did clear it out.

Here is the text file from scanning the 21*4 chart:

LGOROWLENGTH	4
CREATED	"7/26/2008"  # Time: 17:42
INSTRUMENTATION	"Eye-One Pro"
MEASUREMENT_SOURCE	"Illumination=D50  ObserverAngle=2° 
WhiteBase=Absolute  Filter=No"
KEYWORD	"SampleID"
KEYWORD	"SAMPLE_NAME"
NUMBER_OF_FIELDS	9
BEGIN_DATA_FORMAT
SampleID	SAMPLE_NAME	GRAY	XYZ_X	XYZ_Y	XYZ_Z	LAB_L	LAB_A	LAB_B
END_DATA_FORMAT
NUMBER_OF_SETS	84
BEGIN_DATA
1	A1	30.00	45.77	46.86	38.55	74.10	1.67	0.15
2	A2	95.00	1.69	1.64	1.27	13.46	2.86	1.07
3	A3	30.00	45.71	46.81	38.47	74.07	1.64	0.20
4	A4	95.00	1.77	1.72	1.36	13.97	2.77	0.73
5	B1	70.00	11.11	11.07	8.17	39.69	3.23	3.47
6	B2	55.00	20.23	20.46	15.85	52.35	2.47	2.45
7	B3	70.00	11.22	11.20	8.35	39.91	3.10	3.21
8	B4	55.00	20.39	20.60	16.01	52.51	2.56	2.34
9	C1	5.00	80.42	83.18	73.50	93.09	0.43	-4.36
10	C2	15.00	64.64	66.74	58.46	85.37	0.65	-3.53
11	C3	5.00	80.15	82.92	73.41	92.98	0.39	-4.48
12	C4	15.00	64.32	66.39	57.97	85.20	0.69	-3.33
13	D1	45.00	29.23	29.68	23.65	61.38	2.35	1.53
14	D2	80.00	5.78	5.68	4.10	28.60	3.50	3.36
15	D3	45.00	29.20	29.68	23.68	61.38	2.24	1.47
16	D4	80.00	5.84	5.74	4.16	28.74	3.47	3.24
17	E1	85.00	3.71	3.60	2.54	22.32	3.65	3.40
18	E2	40.00	34.15	34.79	27.97	65.58	2.12	1.20
19	E3	85.00	3.86	3.76	2.71	22.86	3.50	2.93
20	E4	40.00	34.14	34.78	27.98	65.57	2.13	1.17
21	F1	20.00	57.38	59.14	51.13	81.37	0.89	-2.65
22	F2	0.00	87.34	90.48	80.46	96.20	0.18	-4.91
23	F3	20.00	57.54	59.32	51.15	81.47	0.83	-2.50
24	F4	0.00	87.25	90.39	80.38	96.16	0.19	-4.91
25	G1	60.00	16.81	16.94	12.93	48.18	2.71	2.82
26	G2	65.00	13.91	13.96	10.52	44.17	2.87	3.08
27	G3	60.00	16.93	17.08	13.09	48.36	2.60	2.68
28	G4	65.00	14.05	14.11	10.70	44.39	2.80	2.89
29	H1	100.00	1.43	1.44	1.31	12.23	1.30	-1.58
30	H2	25.00	51.74	53.23	45.10	78.01	1.08	-1.45
31	H3	100.00	1.52	1.53	1.37	12.77	1.34	-1.39
32	H4	25.00	51.90	53.41	45.26	78.12	1.07	-1.46
33	I1	35.00	40.17	41.00	33.39	70.17	2.01	0.63
34	I2	90.00	2.62	2.54	1.87	18.10	3.26	2.24
35	I3	35.00	40.03	40.88	33.20	70.09	1.92	0.77
36	I4	90.00	2.75	2.68	2.00	18.70	3.14	1.90
37	J1	75.00	8.43	8.36	6.14	34.73	3.27	3.34
38	J2	50.00	24.55	24.93	19.66	57.01	2.24	1.87
39	J3	75.00	8.51	8.45	6.24	34.90	3.18	3.17
40	J4	50.00	24.74	25.12	19.91	57.19	2.25	1.67
41	K1	10.00	72.00	74.38	65.80	89.10	0.59	-4.27
42	K2	10.00	72.26	74.66	65.97	89.23	0.58	-4.21
43	K3	10.00	72.21	74.60	65.91	89.21	0.58	-4.20
44	K4	10.00	72.18	74.58	65.94	89.20	0.55	-4.24
45	L1	50.00	24.55	24.90	19.66	56.97	2.38	1.82
46	L2	75.00	8.54	8.47	6.25	34.94	3.31	3.21
47	L3	50.00	24.58	24.97	19.79	57.04	2.17	1.66
48	L4	75.00	8.62	8.55	6.34	35.10	3.36	3.06
49	M1	90.00	2.57	2.49	1.81	17.88	3.31	2.41
50	M2	35.00	40.00	40.86	33.30	70.08	1.88	0.60
51	M3	90.00	2.75	2.68	1.99	18.71	3.21	2.06
52	M4	35.00	39.95	40.78	33.14	70.02	1.98	0.74
53	N1	25.00	51.53	53.02	45.18	77.89	1.07	-1.76
54	N2	100.00	1.41	1.42	1.27	12.10	1.28	-1.38
55	N3	25.00	51.86	53.38	45.26	78.10	1.02	-1.50
56	N4	100.00	1.51	1.52	1.37	12.73	1.37	-1.49
57	O1	65.00	13.99	14.03	10.57	44.27	2.95	3.08
58	O2	60.00	16.96	17.11	13.16	48.39	2.61	2.54
59	O3	65.00	14.08	14.14	10.71	44.43	2.83	2.91
60	O4	60.00	17.29	17.44	13.49	48.81	2.63	2.37
61	P1	0.00	87.03	90.17	80.49	96.07	0.17	-5.15
62	P2	20.00	57.57	59.37	51.45	81.49	0.81	-2.78
63	P3	0.00	87.10	90.24	80.51	96.10	0.17	-5.11
64	P4	20.00	58.10	59.91	51.81	81.79	0.81	-2.68
65	Q1	40.00	34.38	34.97	28.31	65.72	2.28	0.87
66	Q2	85.00	3.93	3.83	2.77	23.12	3.50	2.90
67	Q3	40.00	34.24	34.88	28.18	65.66	2.10	0.98
68	Q4	85.00	4.03	3.94	2.91	23.48	3.30	2.50
69	R1	80.00	5.67	5.56	3.97	28.27	3.66	3.60
70	R2	45.00	29.19	29.69	23.84	61.38	2.18	1.19
71	R3	80.00	5.94	5.85	4.27	29.03	3.37	3.08
72	R4	45.00	29.57	30.07	24.17	61.71	2.21	1.16
73	S1	15.00	63.77	65.78	57.70	84.89	0.79	-3.60
74	S2	5.00	80.09	82.89	73.91	92.97	0.33	-4.94
75	S3	15.00	64.64	66.73	58.51	85.37	0.68	-3.59
76	S4	5.00	80.28	83.07	73.88	93.05	0.36	-4.77
77	T1	55.00	20.40	20.63	16.03	52.54	2.49	2.33
78	T2	70.00	11.50	11.49	8.64	40.40	3.04	2.96
79	T3	55.00	20.48	20.75	16.22	52.67	2.33	2.10
80	T4	70.00	11.51	11.49	8.63	40.39	3.15	2.98
81	U1	95.00	1.68	1.64	1.27	13.50	2.60	1.05
82	U2	30.00	46.22	47.37	39.25	74.42	1.54	-0.24
83	U3	95.00	1.75	1.70	1.30	13.82	2.82	1.20
84	U4	30.00	46.06	47.20	39.02	74.32	1.57	-0.12
END_DATA

I don't think that there are any radical outliers here that would
explain the curve shape.  Here is the linearisation output:

QTR-Linearize-Data version 2.5.2.0
File: C:\Program Files\QuadToneRIP\Eye-One\IS3 Ilf Gls
2880\IS3-ILfGlss-neut-2880-55-UL-out.txt
Step	Dens	Lab	A	B	
0.00	0.044	96.13	0.18	-5.02	-        b                    a          
               L  +
5.00	0.081	93.02	0.38	-4.64	-          b                  |a         
             L    +
10.00	0.128	89.18	0.57	-4.23	-            b                | a       
            L      +
15.00	0.178	85.21	0.70	-3.51	-              b              | a       
          L        +
20.00	0.226	81.53	0.84	-2.65	-                  b          |  a      
       L           +
25.00	0.274	78.03	1.06	-1.54	-                      b      |   a     
     L             +
30.00	0.328	74.23	1.61	-0.00	-                            b|     a   
   L               +
35.00	0.389	70.09	1.95	0.69	-                             | b    a   
L                 +
40.00	0.458	65.63	2.16	1.06	-                             |   b   aL 
                  +
45.00	0.526	61.46	2.25	1.34	-                             |    bL a  
                  +
50.00	0.603	57.05	2.26	1.75	-                             |   L  b a 
                  +
55.00	0.686	52.52	2.46	2.31	-                             |L       b 
                  +
60.00	0.766	48.44	2.64	2.60	-                            L|         b
                  +
65.00	0.852	44.32	2.86	2.99	-                         L   |          b
                 +
70.00	0.947	40.10	3.13	3.16	-                       L     |          
b                 +
75.00	1.073	34.92	3.28	3.19	-                   L         |          
ba                +
80.00	1.244	28.66	3.50	3.32	-                L            |          
 ba               +
85.00	1.422	22.95	3.49	2.93	-            L                |          b
a                +
90.00	1.586	18.35	3.23	2.15	-          L                  |       b  
a                 +
95.00	1.776	13.69	2.76	1.01	-       L                     |   b      a
                 +
100.00	1.831	12.46	1.32	-1.46	-      L                b     |    a   
                    +

LINEARIZE="96.1325 93.0225 89.185 85.2075 81.53 78.03 74.2275 70.09
65.6325 61.4625 57.0525 52.5175 48.435 44.315 40.0975 34.9175 28.66
22.945 18.3475 13.6875 12.4575"


As you can see, it's non-linear towards the black end, but it's not
the worst I've seen.  I'm sure I've linearised this sort of thing before,

F_P

Not of lot of response ... 

Given that the 95% black value was much closer to 100 than to 90, I
decided that my problem was I had set the default and thus the black
ink limit too high.  So I set it to 50% and redid the ink separation
and linearisation.  The curve looks a lot better:

     http://www.ferdinand-paris.com/2400_less_bumpy_curve.gif

I can linearise and profile this fairly successfully.

In working with gloss I am discovering two things:

1.  The density of the 100% black patch on the ink separation print
with 50% (or whatever) ink calibration set is not as black as the 100%
patch on the 21x4 random test chart printed with a 50% ink limit.  The
test chart prints significantly darker, which I think was the source
of my problem.  Why is this?  It means that you really can't rely on
the ink separation prints to set the ink limit precisely.

2.  There's a lot of drying time needed.  The density measurements are
significantly higher on the separation print and the test charts (i.e.
more density) with an *extra* day's drying.  Patience is needed to
create these curves.

F_P

<ferdinand_paris@...> wrote:
> 2	A2	95.00	13.46	
> 54	N2	100.00	12.10	

Ferdinand,

Those "L" values are a bit high for glossy, more like matte?  Do you 
have the right K ink in?

My glossy have been in the "7" to "9" range on Epson Premium Semi-Gloss 
without pushing for best possible. That one was with the Epson K2 Photo 
Black ink.

Here are my Epson K2 Photo Black values on the first 21 step chart.  
You can see a couple of inversions in the L values. This is at 100%.

This is where the "polishing your print with a cloth" technique comes 
in handy. I am too lazy though, I just settled for lower K values. ;>)

I think I wound up setting the ink limit at "55", and got a 21 step 
value of "9.1" at 100.  

I was really trying to open the curves up in the highlights for 
portraits though.



BLACK			
1	A1	0	94.0
2	B1	5	69.0
3	C1	10	50.7
4	D1	15	35.0
5	E1	20	23.4
6	F1	25	16.0
7	G1	30	13.3
8	H1	35	11.5
9	I1	40	10.6
10	J1	45	10.2
11	K1	50	9.5
12	L1	55	8.7
13	M1	60	8.7
14	N1	65	8.9
15	O1	70	9.3
16	P1	75	7.4
17	Q1	80	7.6
18	R1	85	7.4
19	S1	90	7.3
20	T1	95	10.4
21	U1	100	6.6



Best,
Michael

I'm getting lower dmax than for matte, but if I push it too far (60%),
QTR won't linearise, and if I back off part way (55%) I get the bumpy
curves.  50% seems to give a reasonable compromise.  I may still be
able to get lower dmax with these longer drying times I'm using now.

Are you really linearising your curves?  I find it hard to believe
that the curve creator is able to linearise with that sort of shadow
compression and "inversion".  And if it did somehow, surely there are
blocked up shadows alongside your open highlights?  Probably blocked
up midtones as well.

F_P

--- In QuadtoneRIP@yahoogroups.com, "Michael T. Murphy"
<uriel_bear@...> wrote:

>
> Here are my Epson K2 Photo Black values on the first 21 step chart.  
> You can see a couple of inversions in the L values. This is at 100%.
> 
> This is where the "polishing your print with a cloth" technique comes 
> in handy. I am too lazy though, I just settled for lower K values. ;>)
> 
> I think I wound up setting the ink limit at "55", and got a 21 step 
> value of "9.1" at 100.  
> 
> I was really trying to open the curves up in the highlights for 
> portraits though.
> 
> 
> 
> BLACK			
> 1	A1	0	94.0
> 2	B1	5	69.0
> 3	C1	10	50.7
> 4	D1	15	35.0
> 5	E1	20	23.4
> 6	F1	25	16.0
> 7	G1	30	13.3
> 8	H1	35	11.5
> 9	I1	40	10.6
> 10	J1	45	10.2
> 11	K1	50	9.5
> 12	L1	55	8.7
> 13	M1	60	8.7
> 14	N1	65	8.9
> 15	O1	70	9.3
> 16	P1	75	7.4
> 17	Q1	80	7.6
> 18	R1	85	7.4
> 19	S1	90	7.3
> 20	T1	95	10.4
> 21	U1	100	6.6
> 
> 
> 
> Best,
> Michael
>

<ferdinand_paris@...> wrote:
> 
> Are you really linearising your curves?  
>

That was the first 21 step curve at 100%. I just wanted you to see 
what the black looked like at unreduced flow.

I set my limit at 55%, which gave me a "9.1" L value for the dmax on 
the PK when linerized. Just above where the inversion first seemed to 
occur around 8.7.

I also have to let my prints dry overnight or I can't linerize.

Here are the values that I think I linerized for a 4K+GLOP ink set on 
Epson Premium Semi-Gloss, with the 55% limit:

0	93.1
5	91.4
10	87.9
15	84.0
20	80.0
25	75.0
30	70.1
35	65.6
40	61.6
45	57.0
50	51.4
55	44.6
60	37.2
65	31.1
70	27.9
75	23.8
80	20.3
85	16.5
90	14.6
95	12.7
100	8.8

These were my settings for the "Grey Curve." But again, this was for 
a highlight biased ink set for portraits with GLOP:

	High	Shadows	Overlap	Gamma
Grey = 	75	10	15	1.5


And my density and limit settings:

PK = 	55 density overall	
LK = 	40	70
C = 	22	100
M = 	14	100


Hope that helps some?  Good luck!

Sorry for the slow response. I posted another time before I noticed 
the high L value for the K max. I then deleted that one, 'cause I 
think I was wrong. ;>)

Best,
Michael