Thread: [Matplotlib-users] CMYK

Hi all,

I need to produce figures with CMYK colours, preferably vector-based.

There are two old threads, one from November 2007 and one from August 2010,
regarding this topic:
- http://matplotlib.1069221.n5.nabble.com/rgb-versus-cmyk-tp32391.html
- http://matplotlib.1069221.n5.nabble.com/CMYK-images-td16339.html

However, they only provide some hacks and workarounds, no
matplotlib-integrated solution. Furthermore, some links in these threads are
broken, and other solutions require Adobe products.

I was wondering if anything changed regarding this within the last 2.5 years
since the last thread. Is there a way to produce CMYK with matplotlib?

Many thanks,
Dieter




--
View this message in context: http://matplotlib.1069221.n5.nabble.com/CMYK-tp40352.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

On 29/01/13 03:37:51 -0800, Dieter wrote:
> I was wondering if anything changed regarding this within the last 2.5 years
> since the last thread. Is there a way to produce CMYK with matplotlib?

Hello everybody,

I would be also interested in how to produce CMYK graphics without
external fiddling.

Cheers,
Ignas

We don't currently have any support -- and we're still struggling in 
certain areas supporting RGBA consistently across the system.

I think this would take someone writing a MEP (as a preliminary study of 
all of the changes that would be involved) and then shepherding it 
through implementation.

Mike

On 01/30/2013 11:10 AM, Ignas Anikevičius wrote:
> On 29/01/13 03:37:51 -0800, Dieter wrote:
>> I was wondering if anything changed regarding this within the last 2.5 years
>> since the last thread. Is there a way to produce CMYK with matplotlib?
> Hello everybody,
>
> I would be also interested in how to produce CMYK graphics without
> external fiddling.
>
> Cheers,
> Ignas
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_jan
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On 2013/01/30 6:43 AM, Michael Droettboom wrote:
> We don't currently have any support -- and we're still struggling in
> certain areas supporting RGBA consistently across the system.
>
> I think this would take someone writing a MEP (as a preliminary study of
> all of the changes that would be involved) and then shepherding it
> through implementation.

My somewhat vague recollection is that CMYK is fundamentally 
output-device dependent, and therefore it really doesn't make much sense 
for a plotting library to support it directly.  The conversion from RGBA 
should be made by the publisher, knowing what the output device 
characteristics are.

Eric

>
> Mike
>
> On 01/30/2013 11:10 AM, Ignas Anikevičius wrote:
>> On 29/01/13 03:37:51 -0800, Dieter wrote:
>>> I was wondering if anything changed regarding this within the last 2.5 years
>>> since the last thread. Is there a way to produce CMYK with matplotlib?
>> Hello everybody,
>>
>> I would be also interested in how to produce CMYK graphics without
>> external fiddling.
>>
>> Cheers,
>> Ignas
>>
>> ------------------------------------------------------------------------------
>> Everyone hates slow websites. So do we.
>> Make your web apps faster with AppDynamics
>> Download AppDynamics Lite for free today:
>> http://p.sf.net/sfu/appdyn_d2d_jan
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_jan
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

For what it's worth.

While the RGB system is native to monitor devices, since they produce
light of certain colours, CMYK is the colour system of printer
materials etc. since they absorb the colours, but reflect those we
see.  That means designs must be made in CMYK for pronter materials
and in RGB for our devices. The response of each medium or device is
different. RGB will have part of the colour space not accessible in
some devices, while in printed materials it is different again. The
basic thing is colour space, while RGB and CMYK can be seen as a map.
In the real world you have to look at the product to see if the
colours come out right.

Not sure what to make of any implementation of this, but a simple
mapping should not be impossible.

Cheers,

   Paul

On Wed, Jan 30, 2013 at 6:38 PM, Eric Firing <ef...@ha...> wrote:
> On 2013/01/30 6:43 AM, Michael Droettboom wrote:
>> We don't currently have any support -- and we're still struggling in
>> certain areas supporting RGBA consistently across the system.
>>
>> I think this would take someone writing a MEP (as a preliminary study of
>> all of the changes that would be involved) and then shepherding it
>> through implementation.
>
> My somewhat vague recollection is that CMYK is fundamentally
> output-device dependent, and therefore it really doesn't make much sense
> for a plotting library to support it directly.  The conversion from RGBA
> should be made by the publisher, knowing what the output device
> characteristics are.
>
> Eric
>
>>
>> Mike
>>
>> On 01/30/2013 11:10 AM, Ignas Anikevičius wrote:
>>> On 29/01/13 03:37:51 -0800, Dieter wrote:
>>>> I was wondering if anything changed regarding this within the last 2.5 years
>>>> since the last thread. Is there a way to produce CMYK with matplotlib?
>>> Hello everybody,
>>>
>>> I would be also interested in how to produce CMYK graphics without
>>> external fiddling.
>>>
>>> Cheers,
>>> Ignas
>>>
>>> ------------------------------------------------------------------------------
>>> Everyone hates slow websites. So do we.
>>> Make your web apps faster with AppDynamics
>>> Download AppDynamics Lite for free today:
>>> http://p.sf.net/sfu/appdyn_d2d_jan
>>> _______________________________________________
>>> Matplotlib-users mailing list
>>> Mat...@li...
>>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>>
>> ------------------------------------------------------------------------------
>> Everyone hates slow websites. So do we.
>> Make your web apps faster with AppDynamics
>> Download AppDynamics Lite for free today:
>> http://p.sf.net/sfu/appdyn_d2d_jan
>> _______________________________________________
>> Matplotlib-users mailing list
>> Mat...@li...
>> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>>
>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_jan
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users



-- 

* * * * * * * * http://www.mssl.ucl.ac.uk/~npmk/ * * * *
Dr. N.P.M. Kuin      (n....@uc...)
phone +44-(0)1483 (prefix) -204256 (work) -276110 (home)
mobile +44(0)7806985366  skype ID: npkuin
Mullard Space Science Laboratory  – University College London  –
Holmbury St Mary – Dorking – Surrey RH5 6NT–  U.K.

On 2013/01/30 9:13 AM, Paul Kuin wrote:
> For what it's worth.
>
> While the RGB system is native to monitor devices, since they produce
> light of certain colours, CMYK is the colour system of printer
> materials etc. since they absorb the colours, but reflect those we
> see.  That means designs must be made in CMYK for pronter materials
> and in RGB for our devices. The response of each medium or device is
> different. RGB will have part of the colour space not accessible in
> some devices, while in printed materials it is different again. The
> basic thing is colour space, while RGB and CMYK can be seen as a map.
> In the real world you have to look at the product to see if the
> colours come out right.
>
> Not sure what to make of any implementation of this, but a simple
> mapping should not be impossible.

Granted, a mapping within the intersection of the two spaces 
respectively accessibly to RGB and CMYK is possible, but I think it 
makes more sense to do it as a separate operation on the ps or pdf file 
than to try to build it into mpl.  If it were to be built in, I think it 
would have to be bolted onto the ps and pdf backends.  I suspect that 
the alpha channel will make this quite complicated, much more so than a 
simple mapping; it will require an intermediate rendering step.

Eric

>
> Cheers,
>
>     Paul
>
> On Wed, Jan 30, 2013 at 6:38 PM, Eric Firing <ef...@ha...> wrote:
>> On 2013/01/30 6:43 AM, Michael Droettboom wrote:
>>> We don't currently have any support -- and we're still struggling in
>>> certain areas supporting RGBA consistently across the system.
>>>
>>> I think this would take someone writing a MEP (as a preliminary study of
>>> all of the changes that would be involved) and then shepherding it
>>> through implementation.
>>
>> My somewhat vague recollection is that CMYK is fundamentally
>> output-device dependent, and therefore it really doesn't make much sense
>> for a plotting library to support it directly.  The conversion from RGBA
>> should be made by the publisher, knowing what the output device
>> characteristics are.
>>
>> Eric
>>
>>>
>>> Mike
>>>
>>> On 01/30/2013 11:10 AM, Ignas Anikevičius wrote:
>>>> On 29/01/13 03:37:51 -0800, Dieter wrote:
>>>>> I was wondering if anything changed regarding this within the last 2.5 years
>>>>> since the last thread. Is there a way to produce CMYK with matplotlib?
>>>> Hello everybody,
>>>>
>>>> I would be also interested in how to produce CMYK graphics without
>>>> external fiddling.
>>>>
>>>> Cheers,
>>>> Ignas

I agree with Eric that what we need is a backend that support CMYK color
space.
But matplotlib may need to provide some framework for handling the color
profiles etc.

My limited experience with ps_myck backend (
https://github.com/leejjoon/mpl_ps_cmyk) suggests that, as far as
matplotlib provide some framework for color conversion,
implementing/modifying a backend to support cmyk should not be difficult.

So, yes, we need someone to write a MEP.

Regards,

-JJ



On Thu, Jan 31, 2013 at 4:30 AM, Eric Firing <ef...@ha...> wrote:

> On 2013/01/30 9:13 AM, Paul Kuin wrote:
> > For what it's worth.
> >
> > While the RGB system is native to monitor devices, since they produce
> > light of certain colours, CMYK is the colour system of printer
> > materials etc. since they absorb the colours, but reflect those we
> > see.  That means designs must be made in CMYK for pronter materials
> > and in RGB for our devices. The response of each medium or device is
> > different. RGB will have part of the colour space not accessible in
> > some devices, while in printed materials it is different again. The
> > basic thing is colour space, while RGB and CMYK can be seen as a map.
> > In the real world you have to look at the product to see if the
> > colours come out right.
> >
> > Not sure what to make of any implementation of this, but a simple
> > mapping should not be impossible.
>
> Granted, a mapping within the intersection of the two spaces
> respectively accessibly to RGB and CMYK is possible, but I think it
> makes more sense to do it as a separate operation on the ps or pdf file
> than to try to build it into mpl.  If it were to be built in, I think it
> would have to be bolted onto the ps and pdf backends.  I suspect that
> the alpha channel will make this quite complicated, much more so than a
> simple mapping; it will require an intermediate rendering step.
>
> Eric
>
> >
> > Cheers,
> >
> >     Paul
> >
> > On Wed, Jan 30, 2013 at 6:38 PM, Eric Firing <ef...@ha...> wrote:
> >> On 2013/01/30 6:43 AM, Michael Droettboom wrote:
> >>> We don't currently have any support -- and we're still struggling in
> >>> certain areas supporting RGBA consistently across the system.
> >>>
> >>> I think this would take someone writing a MEP (as a preliminary study
> of
> >>> all of the changes that would be involved) and then shepherding it
> >>> through implementation.
> >>
> >> My somewhat vague recollection is that CMYK is fundamentally
> >> output-device dependent, and therefore it really doesn't make much sense
> >> for a plotting library to support it directly.  The conversion from RGBA
> >> should be made by the publisher, knowing what the output device
> >> characteristics are.
> >>
> >> Eric
> >>
> >>>
> >>> Mike
> >>>
> >>> On 01/30/2013 11:10 AM, Ignas Anikevičius wrote:
> >>>> On 29/01/13 03:37:51 -0800, Dieter wrote:
> >>>>> I was wondering if anything changed regarding this within the last
> 2.5 years
> >>>>> since the last thread. Is there a way to produce CMYK with
> matplotlib?
> >>>> Hello everybody,
> >>>>
> >>>> I would be also interested in how to produce CMYK graphics without
> >>>> external fiddling.
> >>>>
> >>>> Cheers,
> >>>> Ignas
>
>
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_jan
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users
>

Thanks everybody for the input. As I see the answer is no, but it could be
implemented.

I did an extensive search, but I even struggle to find a good and practical
solution how to convert a VECTORPLOT RGB to CMYK on a linux system. (One way
I often found would be the Adobe suits, which I do not have.) I gave
mpl_ps_cmyk a go, but execution failed, and the page looks dated.
Furthermore, Adobes seems to provide ICCs only for Windows and Mac, but not
for Linux. ImageMagick rasterizes the figure, the same with GIMP.

I agree that this should be done on the publisher's side, but as a matter of
fact it is the requirement of some journals.

Is there really no practical way to do this? How do others convert RGB plots
to CMYK? (Importing my data into Matlab and plotting them there cannot be
the only possibility!)

Thanks everybody again, much appreciated!
Dieter



--
View this message in context: http://matplotlib.1069221.n5.nabble.com/CMYK-tp40352p40379.html
Sent from the matplotlib - users mailing list archive at Nabble.com.

For what it's worth:
Take a look at www.littlecms.com,
its' python bindings: https://launchpad.net/pylittlecms

and  http://www.cazabon.com/pyCMS/ which seemingly has been built into PIL.

I don't see the big deal in putting properly tagged RGB files into any publication, and then have the RIP decide what to do with this.
Most of the RIPS will treat untagged RGB as sRGB. Unless you're a weird colour scientist, and know what you're doing, you may just end up doing fine.

For the publications:

ICC Profiles are NOT os dependent. And as a matter of fact, Adobe distributed profiles normally are pretty outdated, to the detriment of all involved in the printing process.

IsoCoatedv2 has evolved as a standard-catch-all cmyk color space, IN EUROPE. The States: not so much. They use SWOP or whatever the Brickworks (Adobe) seem to default.

If the scientific publishers do not accept pdf, but force you to submit word, you shall be fine with RGB, since word only speaks "someuntaggedRGB"

If they insist in CMYK, ask them for the proper profile. Otherwise, you have the same no-control just cast me colours in any direction approach as by using untagged RGB colors. 

For your conversions, you may just need:

http://www.graphicsmagick.org/

Unfortunately, gm does it the chaotic way, which might suffice to get your job done the quick way, yet unpredictable:

convert -colorspace CMYK infile outfile  


hth

Thomas




Am 31.01.2013 um 18:08 schrieb Dieter:

> Thanks everybody for the input. As I see the answer is no, but it could be
> implemented.
> 
> I did an extensive search, but I even struggle to find a good and practical
> solution how to convert a VECTORPLOT RGB to CMYK on a linux system. (One way
> I often found would be the Adobe suits, which I do not have.) I gave
> mpl_ps_cmyk a go, but execution failed, and the page looks dated.
> Furthermore, Adobes seems to provide ICCs only for Windows and Mac, but not
> for Linux. ImageMagick rasterizes the figure, the same with GIMP.
> 
> I agree that this should be done on the publisher's side, but as a matter of
> fact it is the requirement of some journals.
> 
> Is there really no practical way to do this? How do others convert RGB plots
> to CMYK? (Importing my data into Matlab and plotting them there cannot be
> the only possibility!)
> 
> Thanks everybody again, much appreciated!
> Dieter
> 
> 
> 
> --
> View this message in context: http://matplotlib.1069221.n5.nabble.com/CMYK-tp40352p40379.html
> Sent from the matplotlib - users mailing list archive at Nabble.com.
> 
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_jan
> _______________________________________________
> Matplotlib-users mailing list
> Mat...@li...
> https://lists.sourceforge.net/lists/listinfo/matplotlib-users

On Thu, Jan 31, 2013 at 12:08 PM, Dieter <die...@ed...>wrote:

>
>
> Is there really no practical way to do this? How do others convert RGB
> plots
> to CMYK? (Importing my data into Matlab and plotting them there cannot be
> the only possibility!)
>
>
Funny story about that.  I was submitting an article to an IEEE journal
once.  IEEE's submission process for images gives back fairly useful error
messages, and it told me that my images (that I generated from matplotlib)
needed to be in CMYK format.  I had access to Adobe Illustrator on my
wife's computer, and used its tools to convert those files to CMYK, and
resubmitted it to IEEE's submission page.  The error message I got back?
"Images need to be in RGB format"

I forget what I did to resolve this problem (I think I did some funky
eps-->ps-->pdf-->eps thing, I don't remember), but what I submitted was
certainly RGB, so, go figure...

Cheers!
Ben Root

On 1/31/2013 12:55 PM, Benjamin Root wrote:
> I was submitting an article to an IEEE journal once.  IEEE's submission process for images gives back fairly useful error messages, and it told me
> that my images (that I generated from matplotlib) needed to be in CMYK format.  I had access to Adobe Illustrator on my wife's computer, and used its
> tools to convert those files to CMYK, and resubmitted it to IEEE's submission page.  The error message I got back?  "Images need to be in RGB format"


http://matplotlib.org/users/whats_new.html#pgf-tikz-backend

fwiw,
Alan Isaac

Am 30.01.2013 um 19:38 schrieb Eric Firing:
> My somewhat vague recollection is that CMYK is fundamentally 
> output-device dependent,

As is RGB by the way. Define Red: Fire-Engine-Red? Red-as-your-spouses-lips-red? After a glass-of-red-wine-lips-red?

Just in RGB, world and dog settled for the pretty meagre sRGB standard for TV-like display devices (a.k.a. computer screens)

Digital cameras do work better / cover more colours, therefore they should better use AdobeRGB. Alas, mostly it's a layer 8 problem, and there are no profiles or sRGB attached.

You want to go independent: use Lab or Luv or Lch colour spaces.

cheers

Thomas

Thanks everybody, very insightful.
I will specifically have a look at the pgf-tikz-backend, sounds great!
Dieter



--
View this message in context: http://matplotlib.1069221.n5.nabble.com/CMYK-tp40352p40394.html
Sent from the matplotlib - users mailing list archive at Nabble.com.