[argyllcms] Re: Workflow for printing at photo lab

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 26 Mar 2012 12:48:06 +1100

Daniel Bachler wrote:
> I have a question regarding the workflow when printing at a photo lab.

> But just today I got a batch of prints where the colours are pretty
> far from what I wanted. The motive is a portrait with low saturation
> and a skin colour that is relatively pink. In the print the colours
> show a lot less saturation and the skin looks blueish. I just checked
> the new lightroom 4 soft proof as well as photoshop's soft proof (with
> the profile provided by my photo lab) and if "Simulate Paper Color" is
> turned on the image looks very much like the print - lower saturation
> and skin tones and highlights that are shifted into the blue part of
> the spectrum.

Hi,
        it's worth reading this colorsync thread:
<http://lists.apple.com/archives/colorsync-users/2009/Sep/msg00195.html>,
and this post in particular will be of interest (although I recommend
you read the whole thread):
<http://lists.apple.com/archives/colorsync-users/2009/Sep/msg00239.html>

So while in principle it's possible to profile a photo lab, in
practice it may not be possible if they don't have a non-auto
adjusting print mode that you can get reliable access to.

If the process is consistent, then it can be profiled
like any other printing process. It's not clear from your description
whether you tag the jpg's you send them with Adobe RGB or not,
but if they are actually trying to honour the embedded profile,
you probably need to leave it out to access the underlying
print process.

> I guess the "correct" way to handle this problem would be to convert
> the photos into the target colour space (the profile my photo lab
> provides) with a perceptual intent and submit this to the lab. If I
> understand the basics of colour management correctly (big if ;) ),
> then this should counter the colour shifts introduced by the paper
> colour (which I think is the whitepoint?) as best it can.

It depends whether that's really the explanation. More likely (from
the Colorsync thread) is that their process is automatically
adjusting the prints, and/or their profile is largely fiction.
(If they really knew what they were doing, you wouldn't be
reporting a problem !)

> Unfortunately all the labs I know here in Germany only accept sRGB or
> AdobeRGB files as input.

> So here comes my question: Is there a tool/workflow in the argyllcms
> toolchain that I can use to create an AdobeRGB Jpeg that has "photo
> lab compensation" applied to it? 

Yes, although you'll need some tool to convert .tiff to .jpg.

If you have your output (photo lab) profile, create a device link
from your working space (AdobeRGB ?) to the photo lab, and
use cctiff to convert from AdobeRGB to your Photo lab RGB,
then convert to .jpg.

[The lcms tools can probably do a similar pixel processing,
 and may handle .jpg directly.]

You then have the full array of linking options to create
your device link.

Graeme Gill.

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