[scribus] Colour Profiles

[John Beardmore]

Peter Nermander wrote:

>> So are we saying that for every digital camera that ships, the
>> manufacturer should provide a profile which we should select with
>> Scribus ?  If so, what file extension are we looking for ?  I'm not
>> aware of having one, but happy to look.  What if we use pictures from
>> multiple cameras ?  Would we not then need to apply a profile per picture ?
> 
> The problem is that the profile for a camera would depend on the
> ambient light when you take the photo.

If you want to standardise the distribution of colours as opposed to 
reproduce them ?


> But you don't need a profile for the camera, since the camera
> manufacturer put the profile into the camera. The pictures from the
> camera will be in a "standard" colorspace like sRGB or for better
> cameras maybe AdobeRGB.

OK.  And scanners ?

It sounds neat. Our Sony and Fuji cameras seem to offer similar colours. 
Images from our old Kodak are much darker. If they were negatives I'd 
say they'd faded, but I guess the file system would have noticed in 
these digital days.


> Of course the professionals only shoot RAW, and then apply corrections
> to get what they want, but they will still save the resulting image
> (usually a TIFF) using AdobeRGB. You could say that when you use RAW
> you create the profile for each picture while you apply the
> corrections.

OK.  I've never tried raw on my camera. I should experiment !


>> OK -  but again, the paper and ink issues alone make this implausible
>> for those of us that aren't professional printers.
> 
> Not really. The profile is valid for each combinaton of paper and ink.
> As long as you buy the same ink and use the same paper the colors will
> not differ much. And there are companies that create a profile from a
> printed testsheet you send them. You download a file from their
> homepage, print it, send the print by mail to them and get a profile
> back. Not sure of the cost though, but a lot less than buying your own
> equipment to do the calibration.

Quite so.  For those of us that are searching for 'lowest cost of 
ownership' this doesn't sound too promising an approach. And again, I 
need to think in terms of toner rather than ink.


> If you want top quality you should make a new profile each time you
> change ink and each time you open a new pack of paper. But you
> probably don't need to make a new profile that often if you stick to
> the same ink and paper.

We have some favourite papers. We're still looking for the most cost 
effective toners.


>> What I'd like is a means of colour management that may well sacrifice
>> some accuracy, but is quick to use, and can be used with any printer,
>> but gives acceptable results at a cost, and for an amount of effort,
>> that is appropriate to the size and requirements of small jobs that
>> don't need perfect colour, but would benefit from colour that isn't
>> totally uncorrected.
> 
> You have an image, where the printout does not match what you see on
> screen. May I ask why you don't go the easy route and adjust your
> screen so it matches the printer output?  Then you can adjust the image
> on you screen until it looks as you want it, and it will print
> correctly?

 From Scribus we are generally interested in two things, production of 
PDF files for viewing on screen, and the production of printed versions 
of those files, but we use the machines for loads of other stuff at the 
same time, and I wouldn't want to make those other apps harder to use by 
using the screen in a way which makes it harder to read. There are also 
several of us on a number of sites that may get to work on scribus 
documents, and this means that we get to use more than one printer.

But let's focus on Scribus.  When we produce PDFs which look good in 
Scribus and Acrobat, they look similar on the screens used by our 
clients. If we adjust the VDUs we use to match the printer we use the 
most, I guess that will be a pretty bad match for the way our clients 
have their VDUs set up in a typical office.

The various screens we use (laptops and desktops) seem fairly 
consistent, and seem to be similar to our client screens. We tend to use 
them in high but variable ambient light levels.  It would probably be 
quite hard to work if we adjusted the screens to look like print output.

Sooner than calibrate our troglodyte world, I'd be happy to print a 
representative test page from whatever machine I'm working at to 
whatever printer I want to use, then mess with the curves by hand until 
happy.

While this would no doubt be less accurate that fully calibrated CMS, I 
think it would be far less of a nuisance, cheaper and quicker than CMS, 
and better than no correction at all !


> Becuase your result might be because your monitor is not correctly
> adjusted.

:)  Well, it may not be correct for the printer, but it sure is optimal 
for all the other work we do. It doesn't seem sensible to make all the 
other things we do on these machines more difficult just to support 
printing.


> If it is a matter of dark/light pictures, an incorrectly set
> gamma is the most likely cause. Creating a simple profile with gamma
> adjustments is quite easy. Look at for example lprof.

I'll have a look, but I don't see how this approach is better, at least 
in our environment.


Cheers, J/.
-- 
John Beardmore, MSc EDM (Open), B.A. Chem (Oxon), CMIOSH, AIEMA, MEI
Managing Director, T4 Sustainability Limited. http://www.T4sLtd.co.uk/
Energy Audit, Carbon Management, Design Advice, Sustainable Energy
Consultancy and Installation, Carbon Trust Standard Registered Assessor
Phone: 0845 4561332   Mobile: 07785 563116   Skype: t4sustainability