Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Black & White => Topic started by: Jasper on March 21, 2018, 11:07:25 am

Title: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 21, 2018, 11:07:25 am
Just tried printing my first B+W image using QTR and there is a clear green tint  :(

The file I printed was created in Photoshop and saved as 16-bit, Gray Gamma 2.2, TIFF, No compression, Interleaved pixel order, IBM PC byte order.  Image prints neutral from Photoshop/Epson ABW (obviously).

I'm printing directly from QTR (Windows 10) using a user-created curve per the attached screenshots.  Curve Creater tabs not shown in the attachment are left blank (Toner Curve, Toner 2 Curve and Notes).

As I have only selected three Inks (K, LK, LLK), all defined as Gray, I would have thought it was impossible to print with a tint, regardless of other settings (assuming Epson Inks are neutral)?

Any ideas why there is a tint to the image?  Are Epson's K, LK, LLK Inks neutral or not?
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: smthopr on March 21, 2018, 12:17:24 pm
Just tried printing my first B+W image using QTR and there is a clear green tint  :(

The file I printed was created in Photoshop and saved as 16-bit, Gray Gamma 2.2, TIFF, No compression, Interleaved pixel order, IBM PC byte order.  Image prints neutral from Photoshop/Epson ABW (obviously).

I'm printing directly from QTR (Windows 10) using a user-created curve per the attached screenshots.  Curve Creater tabs not shown in the attachment are left blank (Toner Curve, Toner 2 Curve and Notes).

As I have only selected three Inks (K, LK, LLK), all defined as Gray, I would have thought it was impossible to print with a tint, regardless of other settings (assuming Epson Inks are neutral)?

Any ideas why there is a tint to the image?  Are Epson's K, LK, LLK Inks neutral or not?
I think if the inks were really neutral, then the ABW driver would not need to mix in color inks, but it does.  Why not stick with the ABW driver and create a correction profile with QTR?
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 21, 2018, 12:47:59 pm
Smthopr - I don't want to turn this into a ABW versus QTR thread.  I'm trying to find out why a QTR print has a clear color cast. BTW, just because a printer uses color inks in a B+W mode does not mean the gray inks are not neutral.

I had assumed that Epson's K, LK, LLK inks were neutral.  I just need someone that has used QTR with these three Epson inks to confirm (BTW the Printer is P600) and anyone more familior with QTR than I to point me in the right direction.

Thanks.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: digitaldog on March 21, 2018, 01:04:12 pm
Smthopr - I don't want to turn this into a ABW versus QTR thread.  I'm trying to find out why a QTR print has a clear color cast. BTW, just because a printer uses color inks in a B+W mode does not mean the gray inks are not neutral.

I had assumed that Epson's K, LK, LLK inks were neutral.  I just need someone that has used QTR with these three Epson inks to confirm (BTW the Printer is P600) and anyone more familior with QTR than I to point me in the right direction.
Less to do with inks being 'neutral' and how each is mixed! The issue could be metameric failure. Do you see this color cast no matter what light source you view the prints under?
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 21, 2018, 01:13:19 pm
Less to do with inks being 'neutral' and how each is mixed! The issue could be metameric failure. Do you see this color cast no matter what light source you view the prints under?

This isn’t Metamerism. I don’t know what you mean by it not being about whether the inks are neutral. As I am only using 3 inks I think if they are not neutral I won’t have a neutral image.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: digitaldog on March 21, 2018, 01:42:24 pm
This isn’t Metamerism.
IF you understand what Metamerism is, it absolutely isn't that! It may be metameric failure which is totally different. And if you answer the question about how you're viewing the print, we can conclude if this is the case or not.
Do you want to know what Metamerism is? Because we absolutely desire this phenomena!
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 21, 2018, 02:05:21 pm
Hi Andrew, I understand what metamerism is and to answer your question, it does not matter what light I view the print(s) under - they have a clear, visible, constant color cast.  However, I want to keep this thread on track...

I'm trying to find out from those that have used Epson K3 inks in QTR whether they are neutral (specifically for P600 / UltraChrome HD inks).  Obviously with a 3 ink set up, the printer should only be using 1 or 2 inks for a given tone.  So based on what I see, It appears that the K, LK and LLK inks are not neutral. 

However, I do not know exactly what the QTR driver is actually doing.  I assume it is asking the printer to use only these three inks, as that is how I set QTR up, but I am not familiar with QTR so perhaps I made a mistake.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: aaronchan on March 21, 2018, 02:18:01 pm
Epson K3 inks are not even near natural at all!




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Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: digitaldog on March 21, 2018, 02:20:52 pm
Epson K3 inks are not even near natural at all

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Fortunately it doesn’t matter as dead nuts neutral prints are possible. With Epson’s Advanced B&W driver as already mentioned.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 21, 2018, 02:27:04 pm
Epson K3 inks are not even near natural at all!

Thanks Aaron, that's what I wanted to know - at least it confirms I'm not doing anything wrong!
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Stephen Ray on March 22, 2018, 11:23:41 am
Just tried printing my first B+W image using QTR and there is a clear green tint  :( Any ideas why there is a tint to the image?  Are Epson's K, LK, LLK Inks neutral or not?

Can you closely inspect the printed dots with a loupe and tell us what you find? Maybe create some sort of test file with gray swatches using both QTR and ABW?
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 22, 2018, 01:35:29 pm
Can you closely inspect the printed dots with a loupe and tell us what you find? Maybe create some sort of test file with gray swatches using both QTR and ABW?

Hi Stephen - Aaron confirmed why this is in his post above. The Epson black/grey inks have a significant tint (quite strongly green).

Regards
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: digitaldog on March 22, 2018, 02:03:41 pm
Hi Stephen - Aaron confirmed why this is in his post above. The Epson black/grey inks have a significant tint (quite strongly green).
Sigh.... That ignores the FACTS that neutral prints using Epson inks CAN and DO produce neutral output.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 22, 2018, 03:05:03 pm
Sigh.... That ignores the FACTS that neutral prints using Epson inks CAN and DO produce neutral output.

Andrew, I think you’re the one ignoring facts. Read the OP. I clearly state that AWB produces neutral prints. And I clearly state the tint is when using 3K QTR.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: digitaldog on March 22, 2018, 03:38:01 pm
Andrew, I think you’re the one ignoring facts. Read the OP. I clearly state that AWB produces neutral prints. And I clearly state the tint is when using 3K QTR.
He (you) and I are correct and hence, the idea some inks are not neutral is moot! So yeah, you're doing something wrong as you outlined in post on: March 21, 2018, 02:27:04 PM.

Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 22, 2018, 04:44:21 pm
He (you) and I are correct and hence, the idea some inks are not neutral is moot! So yeah, you're doing something wrong as you outlined in post on: March 21, 2018, 02:27:04 PM.

Andrew, I think you have misunderstood this post.  I'm not sure how familiar you are with QTR, but I'll explain the point of my query...

Aaron confirmed this in reply #7, closing my query - i.e. the reason for the tint is because the inks are not neutral, not because I was doing anything incorrectly. 

So knowing this, I know my methods and workflow is good.  Other than the tint, which will obviously be addressed when I move to the piezography inks, the print looks very good (better) compared to the 'stock' Epson ABW prints.

Hope that gives you a better insight to this query.

Regards

Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: digitaldog on March 22, 2018, 04:46:40 pm

So knowing this, I know my methods and workflow is good.  Other than the tint, which will obviously be addressed when I move to the piezography inks, the print looks very good compared to the 'stock' Epson ABW prints.

Hope that gives you a better insight to this query.

Regards
Then you're set and we're all done here.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Stephen Ray on March 22, 2018, 05:26:31 pm
<snip> Other than the tint, which will obviously be addressed when I move to the piezography inks, <snip>

How you do know those inks will be neutral?
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 22, 2018, 05:49:34 pm
Stephen,

There is a choice of Piezography inks to produce neutral or toned prints.  If you are interested in them and want neutral prints they have an inkset which is (quoting them) "designed to be achromatic to the human visual system when printed on a very specific color of white paper: Hahnemuhle Photo Rag. When viewed under full spectrum 5000k a photograph on this paper will appear to be neutral".  Obviously, if one uses a warmer (or colder) paper, the prints will be warmer (or colder) too.

I haven't decided which inkset I'll go with yet, but I certainly won't be going green  :)
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Ferp on March 22, 2018, 07:55:26 pm
I agree with others that the three Epson black inks are not neutral.  I'd have said warm rather than green, but it may depend on which generation Epson inkset you're using.  You can see this by examining the "warm" curves that ship with QTR which use only the thee black inks without any colors added for toning effect.

Both ABW and QTR have to add in small amounts of the color inks to achieve a neutral print.  Unlike Mr Rodney, in my experience neither of them is particularly successful.  I find ABW prints at the neutral setting to be a bit cooler than neutral, and for this reason I can usually spot a "neutral" ABW print in an exhibition.  QTR neutral is a bit warmer than neutral.

You can tweak both approaches to achieve a more neutral print.  It's easier to do this in ABW because there is a color toning wheel in advanced color settings, but it's still trial and error process as the on-screen simulation isn't particularly accurate. Adjusting the toning of an ABW a QTR curve is an advanced process and most users would be better advised just to combine two curves.

The added complication, if you're after exact neutral, is the impact of the paper base color.  You may need to tweak for each paper.  Which is one of the complications of Piezography K7 inks.  Many people don't find their neutral inkset as neutral as they claim, even on Hahnemuhle Photo Rag, but with K7 you can't tweak, other than to change to a different paper. 

The Inkjetmall solution to this is their new Pro inkset, which has both warm and cool tonings that you combine to achieve various effects.  So you could achieve an exact neutral, although it may again be trial and error for each paper.  And you lose part of the attraction of Piezography, as you are reduced from seven to four shades on most printers.  But at least you can tweak

I think exact neutral is over-rated and boring.  Find a subtle toning that you like.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Jasper on March 22, 2018, 08:04:29 pm
The added complication, if you're after exact neutral, is the impact of the paper base color.  You may need to tweak for each paper.  Which is one of the complications of Piezography K7 inks.  Many people don't find their neutral inkset as neutral as they claim, even on Hahnemuhle Photo Rag, but with K7 you can't tweak, other than to change to a different paper. 

The Inkjetmall solution to this is their new Pro inkset, which has both warm and cool tonings that you combine to achieve various effects.  So you could achieve an exact neutral, although it may again be trial and error for each paper.  And you lose part of the attraction of Piezography, as you are reduced from seven to four shades on most printers.  But at least you can tweak

I think exact neutral is over-rated and boring.  Find a subtle toning that you like.

Hi Ferp - I agree with your general sentiment.  Although I wouldn't necessarily call neutral prints "over-rated" or "boring", I do prefer a subtle tone and I will very likely go for that when I switch to piezo (probably selenium).
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: datro on March 23, 2018, 08:27:57 am
I agree with others that the three Epson black inks are not neutral.  I'd have said warm rather than green, but it may depend on which generation Epson inkset you're using.  You can see this by examining the "warm" curves that ship with QTR which use only the thee black inks without any colors added for toning effect.

Both ABW and QTR have to add in small amounts of the color inks to achieve a neutral print.  Unlike Mr Rodney, in my experience neither of them is particularly successful.  I find ABW prints at the neutral setting to be a bit cooler than neutral, and for this reason I can usually spot a "neutral" ABW print in an exhibition.  QTR neutral is a bit warmer than neutral.

You can tweak both approaches to achieve a more neutral print.  It's easier to do this in ABW because there is a color toning wheel in advanced color settings, but it's still trial and error process as the on-screen simulation isn't particularly accurate. Adjusting the toning of an ABW curve is an advanced process and most users would be better advised just to combine two curves.

The added complication, if you're after exact neutral, is the impact of the paper base color.  You may need to tweak for each paper.  Which is one of the complications of Piezography K7 inks.  Many people don't find their neutral inkset as neutral as they claim, even on Hahnemuhle Photo Rag, but with K7 you can't tweak, other than to change to a different paper. 

The Inkjetmall solution to this is their new Pro inkset, which has both warm and cool tonings that you combine to achieve various effects.  So you could achieve an exact neutral, although it may again be trial and error for each paper.  And you lose part of the attraction of Piezography, as you are reduced from seven to four shades on most printers.  But at least you can tweak

I think exact neutral is over-rated and boring.  Find a subtle toning that you like.
+1
Epson K inks are most definitely NOT neutral.

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Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: unesco on March 23, 2018, 01:48:54 pm
Just tried printing my first B+W image using QTR and there is a clear green tint  :(

(...)

Any ideas why there is a tint to the image?  Are Epson's K, LK, LLK Inks neutral or not?

Epson K, LK, LLK inks are not neutral, they are close to mustard/olive tint what is usual to carbon based inks.
There are two approaches for black inks: Canon and HP having near neutral blacks - these are carbon based inks with addition of some cold tint dyes in the liquid. Epson approach is different, inks are warm and neutralisation is done by adding C/M tint directly on paper.

You can receive very neutral prints from QTR, however it is not easy, and one of the highest advantages of QTR is ability of duo/tri toning by curve blending.
ABW is far from neutral, but of course closer than anyone's first attempt to QTR. Many things depend on the paper tint you use, since there is no clear "neutral" definition once you change papers.
Good luck with QTR, it is worth trying if you have a lot of patience! Results can be outstanding.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Ferp on March 24, 2018, 05:49:26 pm
Hi Ferp - I agree with your general sentiment.  Although I wouldn't necessarily call neutral prints "over-rated" or "boring", I do prefer a subtle tone and I will very likely go for that when I switch to piezo (probably selenium).

You should be able to simulate selenium in ABW using the color toning wheel in advanced color settings, although expect a lot of trial and error.  That's simpler than a whole new inkset.  I seem to recall that someone once posted some indicative settings for various tonings in ABW. 

You could probably also do it in QTR if you are running color inks, but that would be a lot harder to achieve.  There was an unfortunate typo in my previous post which I have just corrected.  There is a sentence which was supposed to read "Adjusting the toning of a QTR curve is an advanced process and most users would be better advised just to combine two curves".  For selenium toning you'd need to create a whole new QTR curve.

So for that specific toning a selenium inkset might be simplest, but still involves expense and effort.  And I don't see how you could achieve that toning with the new Piezography Pro inkset which only mixes warm and cool - just one axis on the color wheel.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Stephen Ray on March 25, 2018, 04:12:20 am
I agree with others that the three Epson black inks are not neutral.  I'd have said warm rather than green, but it may depend on which generation Epson inkset you're using.  You can see this by examining the "warm" curves that ship with QTR which use only the thee black inks without any colors added for toning effect.

Both ABW and QTR have to add in small amounts of the color inks to achieve a neutral print.  Unlike Mr Rodney, in my experience neither of them is particularly successful.  I find ABW prints at the neutral setting to be a bit cooler than neutral, and for this reason I can usually spot a "neutral" ABW print in an exhibition.  QTR neutral is a bit warmer than neutral.

You can tweak both approaches to achieve a more neutral print.  It's easier to do this in ABW because there is a color toning wheel in advanced color settings, but it's still trial and error process as the on-screen simulation isn't particularly accurate. Adjusting the toning of an ABW a QTR curve is an advanced process and most users would be better advised just to combine two curves.

The added complication, if you're after exact neutral, is the impact of the paper base color.  You may need to tweak for each paper.  Which is one of the complications of Piezography K7 inks.  Many people don't find their neutral inkset as neutral as they claim, even on Hahnemuhle Photo Rag, but with K7 you can't tweak, other than to change to a different paper. 

The Inkjetmall solution to this is their new Pro inkset, which has both warm and cool tonings that you combine to achieve various effects.  So you could achieve an exact neutral, although it may again be trial and error for each paper.  And you lose part of the attraction of Piezography, as you are reduced from seven to four shades on most printers.  But at least you can tweak

I think exact neutral is over-rated and boring.  Find a subtle toning that you like.

+1. Good info here. Could save one a lot of time and expense.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Alan Goldhammer on March 25, 2018, 08:19:05 am
You should be able to simulate selenium in ABW using the color toning wheel in advanced color settings, although expect a lot of trial and error.  That's simpler than a whole new inkset.  I seem to recall that someone once posted some indicative settings for various tonings in ABW. 
Several years ago I worked with Mark McCormick-Goodhart at Aardenburg to look at the various settings of the Epson ABW toning wheel.  I was doing a lot of printing on Hahnemuhle Photorag Ultra Smooth.  there are 10 different settings that were printed out for testing and you can find the permanency tests on the Aardenburg website.  Obviously some of the settings we looked at would not normally be used for B/W printing but it will give users of Epson inks an idea of the stability of the ABW derived prints (with the caveat that the 3880 inkset has been eclipsed by a newer formulation with a more stable yellow ink).
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Paul Roark on March 29, 2018, 03:41:15 pm
> Just tried printing my first B+W image using QTR and there is a clear green tint ...

My experience mixing inks is that a PK with some cyan in it can be visually darker than a simple PK that is pure carbon.  The cyan is the most lightfast of the color pigments, so putting a little of that in a PK does not weaken it appreciably.  I'm not sure what Epson does, but I've used this approach with some of the MIS inksets that were my designs.  The cyan will give the ink a bit of a green tint in some light.

Paul
www.PaulRoark.com
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Alan Goldhammer on March 29, 2018, 04:44:50 pm
I'm not sure what Epson does, but I've used this approach with some of the MIS inksets that were my designs.  The cyan will give the ink a bit of a green tint in some light.

Paul
www.PaulRoark.com
This review of the Epson 3800 has a picture of the dot pattern for R=G=B=242 in both the normal and ABW modes.  ABW uses both Cyan and Yellow.  I assume the same pattern is still being used in later model printers.  http://www.outbackphoto.com/printinginsights/pi045/essay.html#20070123  (you need to scroll down about 1/2 way to see the two images)
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: IanBarber on July 25, 2019, 05:19:28 pm
I fully agree that the Epson r3880 inks are more on the warm side. Mixing inks even in the ABW Color Wheel to me is a nightmare because I am slightly color blind so one can imagine the frustration this gives me.


I keep flipping over to the ColorByte ImagePrint website and reading about their software, although extremely expensive but they claim their bw profiles are neutral.


If this is the case, for someone like myself who find it hard to distinguish between shades of color, would this be the way to go.
Title: Re: QuadToneRIP QTR - Unexpected Color Tint
Post by: Garnick on July 26, 2019, 07:31:15 am
I've just scanned this thread quickly so I might have missed this.  I think perhaps your best approach is the QTR Yahoo group forum here - https://groups.yahoo.com/neo/groups/QuadtoneRIP/info.  I believe it's at least worth a try.  The folks there are very knowledgeable and often the author of QTR (Roy Harrington) will chime in as well.

EDIT:  The QTR Forum can now be found here - https://groups.io/g/QuadToneRIP/topics   :)

Hope this helps.