On 05/12/2016 10:31 PM, Alexandre Prokoudine wrote:
You are pretty much saying that it is wrong to force freedom of choice upon
people. This doesn't make any sense.
Well certainly the current "Image/Color Management" options do offer
users a lot of choices. But the same choices already were there in more
sensible form with less potential for confusing and misleading the user.
Currently these are the choices in "Image/Color Management":
A. The user can leave the new "Enable Color Management" checked as it is
by default.
B. The user can uncheck "Enable Color Management".
C. The user can assign a new profile, which includes the option to
assign the built-in GIMP sRGB profile.
D. The user can convert the image to a new profile, which includes the
option to convert the image to the GIMP sRGB profile.
E. The user can discard the image's profile, unless the image already is
assigned the GIMP built-in sRGB profile, in which case this option is
grayed out.
(The last option, to save the color profile to disk, literally saves the
image's assigned profile to disk as an ICC profile, so isn't related to
the above-listed options).
Option B seems to provide the user with the option to disable color
management. But this is not what happens. The image is still color
managed. It's still converted from the GIMP built-in sRGB profile to the
user's chosen monitor profile. But if you set GIMP up to display the
image ICC profile in the status bar, you'll see the words "not color
managed". In other words, the status bar is lying to the user.
This "new freedom" provided by unchecking "Enable Color Management"
seems to only be the freedom to internally assign the GIMP sRGB profile
and at the same time be presented with misinformation about whether the
image is actually still color managed.
But the user already has the freedom to assign the sRGB profile to an
image by exercising Option C, which allows the user to assign a new
profile, which already includes the option to assign the built-in GIMP
sRGB profile even if it's the wrong profile for the image
And for non-sRGB images the user already has the freedom to assign the
GIMP built-in sRGB profile by exercising Option E, which really ought to
be relabelled as "Discard the currently assigned ICC profile and assign
the GIMP built-in sRGB profile instead".
So can someone please explain to me what the utility of Options B and E,
that isn't already covered by Option C????
Now let's see what really happens when the user exercises her freedom of
choice and selects one of the "new freedoms" when she's opened a
non-sRGB image.
For the sake of simplicity, let's assume the following:
1. The image is at "Perceptual gamma precision (sRGB) precision rather
than "Linear light" precision.
2. The user has selected "Color managed display" in Preferences/Color
Management.
3. The user chose a real monitor profile in Preferences, instead of
choosing an sRGB ICC profile as the monitor profile. Let's also assume
the user has chosen in Preferences to display the image's ICC profile on
the image status bar.
4. The image is in the ArgyllCMS ClayRGB1998.icm (Adobe-compatible)
color space. Let's also say this hypothetical image has some nice greens
and blues that fall outside the very small sRGB color space gamut:
Before exercising her new freedom of choice, the status bar reads
"Interchangeable with Adobe RGB (1998)" and the image is color-managed
as usual, which is to say that the image is converted from the image's
ICC profile (ClayRGB1998.icm) to the user's monitor profile as selected
in Preferences.
If she now chooses option B and unchecks the option to "Enable Color
Management", here's what happens:
1. The image appearance does in fact change. The image colors are now
washed out because what unchecking "Enable Color Management" really does
is *assign* the GIMP built-in sRGB profile to the image.
2. The status bar says "not color managed". But in fact the image really
still is color managed because the image is still being converted from
the assigned image profile to the monitor profile for display. The
problem is that now the wrong ICC profile has been assigned. So the
status bar is lying to the user, as can be ascertained by changing the
Preferences/Color Management "Image display mode" to "No color management".
If the user really wants the freedom to assign the wrong ICC profile to
an image, well, Option B isn't required as she already has this freedom
from Option C, which allows the user to assign a new ICC profile,
including the GIMP built-in sRGB profile, even if this is the wrong
profile for the image.
Option E is just as bad as Option B. Option E says that it allows the
user to discard the image's ICC profile, and if the image has any ICC
profile other than the GIMP built-in sRGB profile, this option is
available.
So if the user exercises her freedom to discard the image's ICC profile
for the ClayRGB1998 image, what do you think happens?
Well, the image is immediately assigned the GIMP built-in sRGB profile.
And for this particular image which is really a ClayRGB1998 (AdobeRGB
compatible) image, the built-in sRGB profile is the wrong profile to
assign, and so the colors look wrong.
So there is no "new freedom" being given to the user by the new option
to uncheck "Enable Color Management". This option assigns the GIMP
built-in sRGB profile to the image and then pretends that color
management has been disabled, when in reality it hasn't been disabled.
And there's no "new freedom" being given to the user by the option to
"Discard Color Profile", which option actually assigns the GIMP built-in
sRGB profile.
So again, can someone please explain the utility of these new freedoms?
Also, whoever wants to write up GIMP documentation covering the new
freedoms, please feel free to use the above descriptions of what really
happens. I'll be happy to provide a hopefully complete set of cases that
you'll need to cover.
Best,
Elle
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