Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: wolfnowl on April 16, 2009, 03:44:02 am

Title: Gamut Compression/ Colour Conversions
Post by: wolfnowl on April 16, 2009, 03:44:02 am
Hi There:

John Paul Caponigro has recently posted two short videos on his blog site:

1) Visualizing Gamut Compression (http://www.johnpaulcaponigro.com/wordpress/?p=369)
2) Visualizing Colour Space Conversions (http://www.johnpaulcaponigro.com/wordpress/?p=370)
Worth checking out!

Mike.
Title: Gamut Compression/ Colour Conversions
Post by: digitaldog on April 16, 2009, 09:09:19 am
Quote from: wolfnowl
John Paul Caponigro has recently posted two short videos on his blog site:

I'm going to have a serious word with JP about this video. What's with the blue liquid? He should have used a good bottle of wine <g>
Title: Gamut Compression/ Colour Conversions
Post by: bjanes on April 16, 2009, 10:04:02 am
Quote from: digitaldog
I'm going to have a serious word with JP about this video. What's with the blue liquid? He should have used a good bottle of wine <g>
JP does refer to the Digital Camera Space. The DigitalDog should apprise him of proper terminology.  

Bill
Title: Gamut Compression/ Colour Conversions
Post by: digitaldog on April 16, 2009, 10:09:59 am
Quote from: bjanes
JP does refer to the Digital Camera Space. The DigitalDog should apprise him of proper terminology.  

Of course its a digital camera space. I've never said otherwise.
Title: Gamut Compression/ Colour Conversions
Post by: Paul Sumi on April 16, 2009, 08:13:36 pm
Quote from: digitaldog
I'm going to have a serious word with JP about this video. What's with the blue liquid? He should have used a good bottle of wine <g>

I guess that's one way to let your wine breathe  
Title: Gamut Compression/ Colour Conversions
Post by: ggiannini on April 17, 2009, 07:59:56 pm
Quote from: wolfnowl
Hi There:

John Paul Caponigro has recently posted two short videos on his blog site:

1) Visualizing Gamut Compression (http://www.johnpaulcaponigro.com/wordpress/?p=369)
2) Visualizing Colour Space Conversions (http://www.johnpaulcaponigro.com/wordpress/?p=370)
Worth checking out!

Mike.
Hi
I posted about the color space video on these site too.
I do not know if I miss understood the video or not, but I think he saids to take the photo whith the camera setting in ProPhoto, That is right?
Title: Gamut Compression/ Colour Conversions
Post by: digitaldog on April 17, 2009, 08:03:44 pm
Quote from: ggiannini
I do not know if I miss understood the video or not, but I think he saids to take the photo whith the camera setting in ProPhoto, That is right?

He's correctly recommending using ProPhoto RGB for Raw workflows whereby you have the option of picking this as the encoding color space. There's no such setting on the camera which only affects JPEG generation.
Title: Gamut Compression/ Colour Conversions
Post by: papa v2.0 on April 20, 2009, 01:07:40 pm
JP is a bit misleading in his second video. He says that the camera space is smaller than prophoto. A camera can respond to all the wavelengths of the visible spectrum and event those outside it e.g. the camera can respond to wavelegths of say 500nm but this value is outwith the prophoto colour encoding.

I think what he means is that the majority of scene colorimerty is smaller than the prophoto space.

The prophoto RGB primaries were chosen to include the gamut of real-world surface colours without including large areas of encoding space outside the spectrum locus (as  happens with CIE XYZ).

Title: Gamut Compression/ Colour Conversions
Post by: digitaldog on April 20, 2009, 01:22:21 pm
I suspect that once everyone agrees how to map the so called gamut of the camera, we'd see there are large areas of each that probably don't fit for one to say either way. And is a device that captures data we can't see producing color and something we should plot?

Quote
The prophoto RGB primaries were chosen to include the gamut of real-world surface colours without including large areas of encoding space outside the spectrum locus (as happens with CIE XYZ).

Some primaries have to be a compromise or how could we justify, other than the need for a really big space, where the blue primaries fall?