Cool shift - Episode II

#1

Hi Walker,

Me again !
As you know I’ve had a problem of cool shift in my prints in the beginning of the year due to maybe the new ink formulation.

After doing multiple prints this shift was almost completely gone since two weeks (maybe dark tones were a bit cooler than before).

Today I refilled Cool Dark & Cool Medium (half empty), shaked the ink in the bottle before refilling, shaked the cartridge after refilling, had to do some hard cleaning to clear a clogged nozzle (no link), and then the first print I made resulted in a blue shift again !

I don’t understand what is happening !

It seems that the multiple cleaning suck in the fresh ink I had just refilled, I’m pretty sure of it, it seems logic imo, maybe this ink is cooler ok, but why does it come back to “not cooler” without any refill ? That’s what happened last time.

Could it be possible that new ink formulation and the old ink formulation don’t really blend/mix in the cartridge, resulting in some very weird things ?

It comes from the inks but I can’t explain why, it do the rollercoaster on the cool tones, shifting my print to neutral from blue then back to neutral, then back to blue…

Any help will be seriously appreciated,

Best,

Frankie

0 Likes

#2

Some more information.

I printed a target with the stock curve HahPhotoRag_Neutral, to isolate the fact that the problem doesn’t come from the quad I created.

The result is clear, it’s not neutral at all, the dark tones are way cooler than neutral.

Here are the results :

98,27 0,11 0,66
98,27 0,11 0,66
96,62 0,18 0,76
95,59 0,19 0,82
94,61 0,22 0,91
93,56 0,23 0,92
92,23 0,29 0,99
91,18 0,27 1,06
90,15 0,30 1,09
89,11 0,32 1,11
87,75 0,33 1,17
86,90 0,35 1,17
85,94 0,36 1,23
84,96 0,37 1,23
84,02 0,39 1,23
82,77 0,38 1,24
81,77 0,38 1,23
80,75 0,38 1,24
79,69 0,37 1,21
78,45 0,36 1,23
77,47 0,40 1,24
76,63 0,39 1,15
75,60 0,35 1,12
74,38 0,31 1,03
73,37 0,27 0,93
72,39 0,21 0,82
71,54 0,16 0,70
70,48 0,11 0,58
69,12 0,02 0,51
68,26 -0,05 0,42
67,32 -0,14 0,28
66,27 -0,20 0,17
65,04 -0,30 -0,00
64,16 -0,37 -0,07
63,30 -0,43 -0,17
62,46 -0,50 -0,28
61,39 -0,56 -0,35
59,98 -0,67 -0,54
58,98 -0,72 -0,63
57,91 -0,78 -0,70
56,86 -0,86 -0,85
55,62 -0,95 -1,02
54,55 -1,03 -1,12
53,62 -1,12 -1,23
52,56 -1,16 -1,33
51,22 -1,24 -1,47
50,18 -1,33 -1,68
49,35 -1,41 -1,77
48,09 -1,47 -1,93
47,27 -1,62 -2,14
45,69 -1,74 -2,34
44,82 -1,79 -2,44
43,77 -1,87 -2,64
42,77 -1,94 -2,74
41,32 -1,94 -2,98
40,24 -1,94 -2,83
39,30 -1,93 -3,04
38,09 -1,97 -3,24
36,96 -1,94 -3,24
35,57 -1,92 -3,41
34,23 -1,85 -3,56
33,34 -1,77 -3,45
32,02 -1,66 -3,66
30,83 -1,47 -3,56
29,66 -1,05 -3,15
28,58 -0,96 -3,29
27,34 -0,76 -3,40
25,96 -0,41 -3,47
25,04 -0,18 -3,41
24,00 0,21 -3,18
23,28 0,47 -3,03
22,49 0,66 -2,54
21,23 1,10 -1,99
20,82 1,32 -1,22
19,96 1,62 -0,86
19,06 1,85 -0,63
17,87 1,75 -0,29
16,91 1,60 -0,07
16,15 1,52 -0,05
15,42 0,89 0,24
15,12 0,41 0,57

How could it be possible ?

Here is a QTR Calibration print.

And the values for each channel at 100% :

|13,94|0,33|0,41| MK
|49,38|-1,52|-5,52| Cool Light
|96,87|0,68|-0,77| GO
|21,98|1,31|-6,17| Cool Dark
|27,40|-0,56|-6,87| Cool Medium
|23,88|1,23|1,60| Warm Dark
|27,10|1,49|2,33| Warm Medium
|46,49|2,66|6,13| Warm Light
|66,96|2,68|7,29| Warm Very Light
|68,77|0,19|-2,72| Cool Very Light

Do you see something weird ?

0 Likes

#3

Actually, I think you have residual color pigment from the old formulation at the bottom of your dampers that gets stirred up during a power cleaning. Complicated though . . .

-W

0 Likes

#4

So you confirm that the values are cooler than expected ? If yes in wich channel ?

May it be possible that the old pigments settle at the bottom of the cartridge, then mix with the fresh ink when I refill and agitate, then re-settled in the bottom of the cartridge after some days ?

That could explain why there is more blue pigments in the first prints (fresh ink + old pigments) and then it come back to normal when the old pigments settle again in the bottom of the cartridge ?

I don’t know how the damper work.

Frankie

0 Likes

#5

There is about 45mL of ink between the cartridge and head. Most of this is directly above the head in the damper. So changing the carts doesn’t change the ink coming out of the head. Doing a power clean can if the dampers have old pigment.

We have perhaps over 50 or 60 of these printers running with pro ink (new and old) without the issue though so that is why I said it’s complicated and may indicate another issue.

-Walker

0 Likes

#6

Ok I understand, that confirm that it is a liquid problem with some pigments settling somewhere.

What is weird is that the first time it happened it happened about 2 weeks after refilling the cartridge, I was thinking that this corresponded to the time/number of prints we did before the new ink actually hit the print head.
I don’t remember if I did any power cleaning the first time it happened.

0 Likes

#7

After some prints, neutral is now back to almost perfect, bue shift is gone.

In order to resolve the future problems I would like to test if the settled pigments are in the damper or in the cartridge.

If I do a Power Clean then a print, in the case that this print is neutral, can this diagnosticate the fact that the damper don’t have settled pigment ? (I don’t know the proximity between the damper and the head and if only a single Power Clean can move ink through damper to the head)

Best,

Frankie

0 Likes

#8

Hi, some update.

After changing the cool cartridges, the ink selector (damper) & the print head, my Lab Neutral on Photo Rag 308 (± 0,3 for b except for the extremes values) is the result of this blending (% of warm) : 10-30-60.

Do you find theses values “normal” ?

Here’s a screenshot of the graph for b values resulting from the blend.
Left is highlight, right is shadow.

Best,

Frankie

0 Likes

#9

This is very neutral

-Walker

0 Likes

#10

But the values 10-30-60 for the blending looks right to you ?
I find the split very far from the “recommended” 28%.

0 Likes

#11

The average of those numbers is 36.66%. Not far off.

But no, in reality, the lighter the ink the less color you have and the more you have to move the split to effect the AB* value. You are in the ballpark. The graph above is misleading (not to say YOU are, just the image) as it’s only +/- one degree.

-Walker

1 Like