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Re: [OM] cobalt profiles

Subject: Re: [OM] cobalt profiles
From: Wayne Shumaker <om3ti@xxxxxxxx>
Date: Mon, 14 Mar 2022 19:16:21 -0700
At 3/14/2022 03:29 PM, Moose wrote:

>On 3/14/2022 8:49 AM, Wayne Shumaker wrote:
>>I am wondering if anyone on the list has used Cobalt profiles? There is 
>>discussion on FM. One of the examples at the bottom of this page:
>>https://www.cobalt-image.com/basic-pack/
>>of the red flower looks pretty dramatic.
>
>The big change there, and in the larger one at the top of the page, is in 
>pulling down highlights in the red channel, to avoid clipping and loss of 
>detail. I don't need a profile to do that. It is useful to bracketed EV comp 
>in situations known to lead to that problem.

Some further discussion in this link:
https://www.cobalt-image.com/in-the-heart-of-our-basic-profiles/
I found interesting to read.

There are times when the adobe curve can create problems where you can no 
longer pull it down. To quote the article:

"We are therefore in the unfortunate situation of being able to photograph a 
high-contrast scene up to 14 stops, but not being able to represent it as an 
output in a credible way for our senses.

The practical solution to this problem was the introduction of a tonal 
compression curve."
...
"There is no absolute scientific reason for choosing this specific curve, it is 
an empirical choice.
Other software manufacturers have chosen slightly different or even 
significantly different curves. In fact, in Colorimetry there is no concept of 
?curve? in the space of the XYZ tristimulus; all transformations should be 
linear. The presence of this curve makes the representation of the photos on 
our monitors credible to our senses, both in terms of exposure and contrast 
ratio.
There are, however, some secondary effects, typical of RGB curves, which are 
undesirable:..."

Worth noting some of the problems. Pulling down the highlights may fix the 
problem that was created in the first place by the profile tonal curve. Which 
means one is fighting against the profile.

>>We have often discussed different cameras and their colors. But every color 
>>produced by the camera has a profile used to render those colors. As Jim 
>>Kasson has said:
>>https://blog.kasson.com/the-last-word/roles-of-camera-and-raw-developer-in-determining-color/
>>in particular the color profile intent.
>
>I assume that you are aware that Adobe, in LR and ACR, has several camera 
>specific profiles available, as well as many non-specific ones.
>
>Their default profiles seem to be intended to minimize differences between 
>cameras, pushing all toward their idea of correct color. A few years ago, they 
>changed defaults from "Adobe Standard" to "Adobe Color". AGAK commented at the 
>time, opining that the new profile pleased him more.
>
>If a Raw file has been opened before, in LR/ACR, with the "Standard" profile, 
>when it is opened again, it will still use that profile, which is also 
>available by choice for any file.
>
>In any case, there is a way that using the Cobalt profiles is paying to use 
>profiles designed by a small outfit in preference to those done by a big one, 
>which has been at this profiling business much longer, and pay extra for the 
>privilege.
>
>I like the Adobe default profiles. The look a lot better to me, for example, 
>than those in DxO.

I think adobe is trying to cover the widest audience. I also don't necessarily 
think the Cobalt profiles are the ultimate solution. They even advertise the 
basic profiles as just a starting point. I just find it interesting to explore 
and try to understand the reasoning behind it all.

Most photographers don't want to deal with it anyway. And most people don't 
like realistic color rendering.

>>Perhaps if one of the Cobalt basic camera specific calibrated profile is used 
>>for camera comparison, will there is still a significant difference when 
>>comparing recent camera models?
>
>I don't know. If you use the Adobe profiles, they tend to minimize differences 
>between cameras.
>
>>I'm not the best color judge by any means. I only notice real differences 
>>with side by side comparisons.
>
>As Meher Baba said, I use the Adobe profiles and "Don't worry, be happy."
>
>As Moose says, no one else here was there, and even if they were, and had 
>perfect visual memory, how does one know whether yours or theirs is "correct".
>
>Everything is going to be viewed on a range of display devices and/or prints, 
>with various biases of their own. Even if one color controls the whole chain, 
>the light under which the results are viewed changes them.
>
>Cameras "see" differently than I do. Quite often, when I push the button, I 
>already know what the result is going to look like, and how I will likely 
>modify it to mirror what I saw. St. Ansel became famous doing this. ð???
>
>My books look different under different natural lights, and under various 
>sorts of interior light. And yet, to the extent that they are of familiar 
>sorts of things and people, viewer's visual systems correct for all that. I've 
>never had anyone say "all these pictures are reddish" when viewing under 
>incandescent.
>
>If I were shooting for catalog repro, I'd be using Sigma Foveon bodies or Oly 
>bodies in HR mode, and profile like crazy, to avoid demosaicing color errors - 
>but I'm not . . .
>
>Other Things Moose

I have mentioned in the past using a linear tonal curve in the profile to avoid 
having to fight against the existing tonal curve. And I do use camera specific 
profiles, which offers a choice for a starting point.

After reading more about these profiles, it does seem one is paying for 
something that may not be that much value add. You have to pay 39 euro per 
camera just for the basic profile.

As you say, our eyes have a way of compensating for a lot. But I still wonder 
about the comments of one camera is better than another, when it may just be 
the profile.

I'm always interested in what goes on behind the curtain.
And if anyone has sleep problems you can read this - Kodak 2000:
http://www.photo-lovers.org/pdf/color/romm.pdf
which I found trying to understand what RIMM ROMM means -
"Reference Input/Output Medium Metric RGB Color Encodings"

WayneS

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