[argyllcms] Re: Extract L*a*b, XYZ values from a target image using scanin

  • From: David Irisarri <zuiko3000@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 11 Feb 2013 19:09:57 -0500

So if you don't create any reference file with the colors you like,
how do you calculate the color matrix based on the uncorrected sensor
color and the color you like?

I would appreciate your help.

David

On Mon, Feb 11, 2013 at 7:06 PM, Ben Goren <ben@xxxxxxxxxxxxxxxx> wrote:
> I take it what you really want is that matrix so that you can compile a 
> custom version of dcraw? If so, I don't think you want to do that the way 
> you're describing....
>
> b&
>
> On Feb 11, 2013, at 4:49 PM, David Irisarri <zuiko3000@xxxxxxxxx> wrote:
>
>> Hi Graeme,
>>
>> Thanks for your reply.
>>
>> I want to do this.
>>
>> 1. Take a picture of the Color Checker chart with the camera and
>> export it in TIFF AdobeRGB (biggest color gamut of the camera, no
>> color patches out of gamut)
>> 2. Extract color values of these patches and create a CGATS file
>> according to these values. I want these values in L*a*b and XYZ.
>> 3. Process the same image with dcraw (no color management raw color)
>> and create a color matrix using the reference previously created.
>>
>> David
>>
>>
>>
>> On Mon, Feb 11, 2013 at 6:35 PM, Graeme Gill <graeme@xxxxxxxxxxxxx> wrote:
>>> David Irisarri wrote:
>>>
>>> Hi,
>>>
>>>> I ma David and I am trying to create a color profile. I would like to ask
>>>> you guys how to extract color values from an image in order to create a
>>>> CGATS file. I am using scanin but it only generates a val file with RGB
>>>> values.
>>>
>>> If you want to interpret the RGB image as CIE values, then you
>>> have to specify the device space using an ICC profile. You
>>> can use the "scanin -c" mode to do this, see
>>> <http://www.argyllcms.com/doc/scanin.html#c>
>>>
>>>> The image I have is in aRGB and at least I would need to extract
>>>> these values in CIE L*a*b. XYZ would also be very welcome.
>>>> I need to extract these values because I want to create a profile according
>>>> to this TIFF image, I don't want to match the colors according to a chart 
>>>> with
>>>> its own values.
>>>
>>> The RGB TIFF is being used as the reference values ?
>>>
>>> Graeme Gill.
>>>
>>>
>>
>
>

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