Archived posting to the Leica Users Group, 2006/06/04

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Subject: [Leica] RE: first PAW colour desaturation (Nathan Wajsman)
From: hoppyman at bigpond.net.au (G Hopkinson)
Date: Sun Jun 4 19:15:18 2006

Hi Nathan, Tina, Bradley
Thanks Nathan for a contribution on this.
Certainly makes sense to reduce the variables as much as possible. And I'm
sure Tina's advice is sound, hence my plea for more info.
I'd welcome further explanation on this as it's an area I'm especially keen
to master.
My query was that I don't understand how the saving as sRGB (down from Adobe
RGB) will alter the on- screen appearance since almost all monitors will not
display better than that standard, anyway.
It's prompted me to go back and examine the images that I've posted in the
LUG gallery.
Where I thought that I'd always standardized on reduction of 16 bit TIFF to
8 bit, then conversion to suitable resolution jpg and keeping the same
colour space (Adobe RGB1998), I found mine vary in both bit depth and colour
profile. Obviously I wasn't being consistent.
It's all valuable learning.

I suspect the secrets in the original issue may involve the difference
between conversion and assigning a profile (as Tina said)
I'm off to hit Google & Adobe

Cheers
Hoppy
Personal sponsor of Fujichrome in Australia
(my salary goes straight in their cash register right now)

------------------------------

From: Nathan Wajsman <nathan@nathanfoto.com>
Subject: Re: [Leica] RE: first PAW colour desaturation
Hi Hoppy,

I am certainly no expert on colour, but the advice from Tina and 
Brandley is correct. If you convert to sRGB before posting to the web, 
and the picture looks like you want it on your screen, then you have a 
reasonable chance that it will look equally good on other people's 
screens--of course, allowing for different monitors, calibration etc. 
But sRGB is a common standard and so a safe choice.

If you leave your image in any other colour space, then the viewer's 
computer will have to convert it to sRGB for display, and then you 
introduce a bunch of additional variables into the process, like what 
kind of colour management software s/he has etc.

Nathan

G Hopkinson wrote:
> Hi Bradley and Tina
> I have a request regarding your suggestion, Tina.
>
> Would you expand on the rationale of your suggestion to convert to sRGB
> colour space before conversion to jpg?
> My understanding is that VERY few monitors can use the full Adobe RGB
space
> or better. I only know of one professional Eizo model, in fact. Maybe
there
> are others but most won't, certainly.
> So it's reasonable to assume that Bradley's will be at best sRGB. Again
> assuming that Bradley and other viewers have calibrated their monitors,
> won't the DISPLAYED image (ignoring printing here) before and after
> conversion to sRGB look the same? I'm assuming that the file is then saved
> as jpg. Saving as gif, which we touched on in another thread certainly can
> give a "desaturated" effect with the reduced palette.
>
> I (thought!) I had a reasonable handle on matters colour space and bit
depth
> and it's important, of course. So I'd really value any further light you
can
> shed on this. Maybe I need to have a quiet lie down, followed by a big
> Google.
>
> Regards,
>
> Hoppy
> Down-under colour management apprentice. 
>    
>------------------------------
> From: bradreiman@aol.com
> Subject: Re: [Leica] my first PAW
> one question-my color photos posted to lug gallery are quite 
> desaturated. its not my monitor as posting to other sights and printing 
> are spot on. has anyone had this same experience? whats your work 
> around? thanks in advance...bradley
> ------------------------------
> 
> From: Tina Manley <images@InfoAve.Net>
 
> Convert them to sRGB first before you save them as jpegs. Be sure you 
> actually convert and don't just assign the profile.

> Tina

> Tina Manley, ASMP, NPPA
> http://www.tinamanley.com