[Digikam-devel] CMS beginner question

[F.J.Cruz]

El Miércoles, 8 de Febrero de 2006 23:11, Thorsten Schnebeck escribió:
> Am Mittwoch 08 Februar 2006 22:38 schrieb Francisco J. Cruz:
> > SVN commit 507273 by fjcruz:
>
> Hi Francisco,

Hi Thorsten,

>
> a small question about ICC. I am a newbie when it comes to cms practice but

Me too!! :-)

> I know the wider basics. So I setup some icc profiles
> 20D.icc for my cam, 171s.icm for my monitor and sRGB as system profile
>

I guess you mean workspace profile when you say "system profile". If I'm right 
about this, maybe you'd have to choose an icc profile with a wider "color 
gamut", like Adobe1998 or similar, that are intended to image edition. But 
this is an advice only, you can use the profile you like, of course :-)

> The RAW file format of the 20D has a dynamic of 4096 levels of intensity.
> The IE uses 16bit dynamic or 65K levels per channel and the standard raw
> convertion results in a dark picture.
> I thought that when I apply a icc profile the 12bit will be extrapolated
> into the 16bit  sRGB color space. This does not happen when I test this
> stuff with 0.9.0-svn.
> Should this work?
>

As probably you know, digiKam use Dave Coffin's dcraw application, and in his 
faq we can read this:

"Why is 16-bit output dark / flattened / unreadable? 
If you want pretty pictures straight out of dcraw, stay with 8-bit output. 
16-bit linear output is the best raw material for professional image editors 
such as  PhotoShop and CinePaint, but it's no good for most image viewers."

After you apply the icc profile, you have to:

1. Adjust wite balance, specially exposure.
2. Adjust curves, you can try some curve files from cinepaint ("point and 
shoot" and "white wedding" family can be good start points)

> A side note: My original Samsung icm profiles occurs unlabeled (no profile
> description) in digiKams profile set-up.
> Shall I mail you this profile so you can check how the profile name is
> tagged?
>

It's not necessary to do it, in fact there are a lot of profiles manufacturers 
that don't "fill" all the fields.

> Bye
>

Bye, I hope I can help you and excuse my poor english. :-)

>   Thorsten
>

Paco.