[argyllcms] Re: Causes of and remedy for black crush
- From: Jos van Riswick <josvanr@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Wed, 31 Jul 2013 10:53:23 +0200
Thnx for all your responses !
Ok yes I might have guessed that the xrite engineers would have thought
about non-perpendicular light hitting the instrument :)
I think in my case the darks dont get clipped, because the shadow detail
re-appears when I move to the side slightly (I mean up/down; my monitor is
on its side :p)
I think Ellen is right. I thought about my process again and remember
having edited the images on a different monitor initially (ips but laptop).
The latter one has quite a severe 'gamma correction due to viewing angle'
effect. I think the problem stems from that...
thnx again !
On Wed, Jul 31, 2013 at 10:40 AM, Jan-Peter Homann <
homann@xxxxxxxxxxxxxxxxxx> wrote:
> Hello list, hello Graeme,
> From my experinece, several applications don´t allow to specify rendering
> intents and use the relative colorimetric intent by default for matching
> e.g. sRGB to to the monitor colorspace.
>
> In this case, profiling a monitor would lead bey default to clipping in
> the shadows, if the monitor itself has not a perfect black.
>
> I think, that more or less all users would prefer to have no clipping and
> instead a slightly lighter appearance of colors at the monitor.
>
> This goal could be reached, if the measurement data is scaled to a perfect
> black before the profile is calculated.
>
> Question:
> Is there any possibility to scale measurement data before a monitor
> profile is calculated ?
>
> Best regards
> Jan-Peter
>
> Am 31.07.13 10:14, schrieb Graeme Gill:
>
> Jan-Peter Homann wrote:
>>
>>> From other ICC-profiling softwares, I have seen, that matrix monitor
>>> profiles are always
>>> scaled to a blackpoint of L* 0 a*0 b*0
>>>
>>> Questions:
>>> - Is the standard setting in ArgyllCMS for monitor profiles different ?
>>>
>> Hi,
>> The profile wouldn't be accurate if it scaled black to 0. The
>> (V2) ICC
>> standard explicitly states that the colorimetric data is not to be scaled
>> to the black
>> point, and matrix profiles don't have the option of different matrices
>> for different
>> intents. To try and second guess such a thing would certainly cause
>> issues with
>> profile interoperability.
>>
>> - Is it possible to create matrxi monitor profiles with perfect black by
>>> a profiling option ?
>>>
>> See above. It's possible to create cLUT profiles that gamut map from the
>> source
>> black to the display black for perceptual and/or saturation intent, or use
>> a CMM with BPC.
>>
>> Graeme.
>>
>>
>>
>>
>
> --
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