Ink quality

[janezl]

Hi,
certain spot color inks (per PMS) supplied from our ink supplier, cause us problems: very high amount of ink neeed, to achieve color value, close to swatchbook reference. Consequently high dot gain and other print problems occur.
Got a hint, that they might be mixing transparent white into ink, although it is not foreseen as basic receipe.
How could I check incoming ink?
Thank,
Janez

[The Heidelberg Guy]

Have all of your PMS mixes to match at 2.5 to 3 Microns, then have them give you a swatch with the micron readings on it. I have had them done like that, but we limited it to 2.5 Micron.

Most bigger ink companies dont nessasarily use the formula that you see in the Pantone guide, they almost always have there custom mixes.

[J]

Have all of your PMS mixes to match at 2.5 to 3 Microns, then have them give you a swatch with the micron readings on it. I have had them done like that, but we limited it to 2.5 Micron.

How is ink thickness in microns measured?

Also isn't the target ink film thickness on the press sheet 1 micron for process colors? Shouldn't it be about the same for a spot color?

J

[Bob Peterson]

Hi,
certain spot color inks (per PMS) supplied from our ink supplier, cause us problems: very high amount of ink neeed, to achieve color value, close to swatchbook reference. Consequently high dot gain and other print problems occur.
Got a hint, that they might be mixing transparent white into ink, although it is not foreseen as basic receipe.
How could I check incoming ink?
Thank,
Janez

Providing you are talking about the standard Pantone colors in the book, Pantone' ink films in some cases are extremely heavy. Also, if you are buying inks that require an Aqueous or UV coating, different pigments must be used that are resistant to bleed/burnout. The pigment substitutions in some cases do not have the same tinctorial strengths or shades in some cases as the pigment used to create the colors in the Pantone book. Therefore, causing a heavier ink film to be run in order to achieve color.

Every ink company matches and QC's colors differently. In my 30-years in the industry, I have seen used many different techniques to match color. However, none of which were consistant with what a press can actually apply. My current employer does have the process down to a science where the ink is actually weighed and applied at a film of roughly 1.5 mil, more in line with what a offset press can actually run/control.

Over the past couple of years I have seen small ink companies selling offshore inks due to the low costs. These companies are able to mix and resell these inks at an extremely low price. We have obtained samples of some of these inks for evaluation and found them to be as much as 20-25% weaker then what we sell.

I would recommend that you order one of the inks that give you trouble from a different ink company and evaluate it for press performance and color reproduction.

If I can be of any assistance please don't hesitate to shoot me a PM.

Regards,
Bob Peterson

[RGPW17100]

Inks heavy in Reflex blue require you to pound it so hard keeping screens open can be a challenge. We really struggle with colors like 293 and 2935. The other problem with reflex is it will dry back red. Red inks to me are easiest to run. Inks with a lot of mixing green tends to mottle on solids. Metallic inks forget it. Get that stuff up to density and keeping screens open is a challenge. Our ink company blames the standards committee. They say that in order to hit some of the colors is almost impossible.

[The Heidelberg Guy]

Providing you are talking about the standard Pantone colors in the book, Pantone' ink films in some cases are extremely heavy. Also, if you are buying inks that require an Aqueous or UV coating, different pigments must be used that are resistant to bleed/burnout. The pigment substitutions in some cases do not have the same tinctorial strengths or shades in some cases as the pigment used to create the colors in the Pantone book. Therefore, causing a heavier ink film to be run in order to achieve color.

Every ink company matches and QC's colors differently. In my 30-years in the industry, I have seen used many different techniques to match color. However, none of which were consistant with what a press can actually apply. My current employer does have the process down to a science where the ink is actually weighed and applied at a film of roughly 1.5 mil, more in line with what a offset press can actually run/control.

Over the past couple of years I have seen small ink companies selling offshore inks due to the low costs. These companies are able to mix and resell these inks at an extremely low price. We have obtained samples of some of these inks for evaluation and found them to be as much as 20-25% weaker then what we sell.

I would recommend that you order one of the inks that give you trouble from a different ink company and evaluate it for press performance and color reproduction.

If I can be of any assistance please don't hesitate to shoot me a PM.

Regards,
Bob Peterson

Very true Bob! Although I think that a 1.5 is a little too strong, Heidelberg presses like the 2.5!

A little FYI - We tested 1.0, 1.5. 2.0, 2.5, 3.0, 3.5 and 4.0 Mill of PMS 293. We ran (7) batches of ink looking for shifting in color, from stop and starts, speed changes, 2% water change + or - and the results were pretty interesting. We measured 100 sheets on the Image control for each batch of ink on each run.

(XL105)
1.0 - 4.2 DeltaE
1.5 - 3.3 DeltaE
2.0 - 2.2 DeltaE
2.5 - 1.4 DeltaE
3.0 - 2.9 DeltaE
3.5 - 3.6 DeltaE
4.0 - 4.4 DeltaE

(CD102)
1.0 - 3.6 DeltaE
1.5 - 3.2 DeltaE
2.0 - 2.5 DeltaE
2.5 - 1.9 DeltaE
3.0 - 2.4 DeltaE
3.5 - 2.9 DeltaE
4.0 - 3.6 DeltaE

The CD102 actually handled the heavier ink films more stable, while he XL105 was locked in at the 2.5 range.

[Cold]

That is very cool Heidleberg Guy. I would bet if you ran the same test on a komori and man roland, you would find the komori locking in closer to 2.0 and the man roland locking in closer to 3.0.

[D Ink Man]

If you compare the ink film thickness of PMS Reflex to PMS Rhodamine, the Reflex takes 2X the film thickness versus Rhodamine to achieve book density. Nuff said, thanks Pantone.

[The Heidelberg Guy]

If you compare the ink film thickness of PMS Reflex to PMS Rhodamine, the Reflex takes 2X the film thickness versus Rhodamine to achieve book density. Nuff said, thanks Pantone.

It all depends on who's bases you use.

[turbotom1052]

ill repeat my feelings on this issue on this thread even though it may rub some people the wrong way. it is my belief that the pms inks that we buy today premixed are being formulated with either less of a pigment load or with weaker pigments or in some cases perhaps even diluted with transparent white. think about it for a minute here. the pigments in ink probably represent the highest cost of all the components in a can of ink. if the ink companies use less pigment or a weaker pigment it becomes a win, win for them. either way they save money on the raw material and then make more money by selling us more ink. this results in problems for us printers as we now have to run a higher ink film thickness to arrive at the desired color. my way around this whenever possible is to try and take a step up in the pms book. as it turns out transparent white is probably the cheapest thing to manufacture. if possible buy a stronger ink extend it with transparent white to match color without having to run such a thick film.