[Tig] When to use 444RGB or 444YUV for Dual link monitoring in a DI

adrian hauser ahauser at bigair.com.au
Sun Aug 5 00:08:58 BST 2007


Thanks Bob,
How much 'color' would you say is lost?
Could this be defined as a loss of saturation as well.
Some of my tests using the RGB Linear output method
have given me a print with excelent reproduction of levels
but over saturated to the tune of about 20%!.

Adrian Hauser.



----- Original Message ----- 
From: "Bob Friesenhahn" <bfriesen at simple.dallas.tx.us>
To: "adrian hauser" <ahauser at bigair.com.au>
Cc: "tig tig" <tig at colorist.org>
Sent: Sunday, August 05, 2007 9:00 AM
Subject: Re: [Tig] When to use 444RGB or 444YUV for Dual link monitoring in 
a DI


> On Sun, 5 Aug 2007, adrian hauser wrote:
>>
>> So given the above variables when does one select 444YUV
>> or 444RGB for dual link monitoring. Aslo when working in
>> YUV I have the options to work in full range 0 - 1023 or
>> 'video range' 64 - 940.
>
> When transforming from original RGB to YUV, there will always be a loss of 
> color since YUV supports a more limited number of colors. This is likely 
> an important consideration for when you want to produce log output.
>
> For video, Rec.709 defines the transform to and from YCbCr ("YUV") and 
> RGB.  It is primarily a YCbCr format which uses "video" levels.  For 
> Rec.709 video output you will surely want to monitor results in YCbCr 
> space with video range so that you will see the final colors.
>
> As a golden rule, your viewing environment should match the target 
> environment as closely as possible in order to assure expected results. 
> Note that if you are sure that your viewing environment matches the final 
> translation to the target device environment, there may be an advantage to 
> working in the original colorspace (while monitoring in the target 
> colorspace) since then you will throw as little away as possible and it 
> will be easier to retarget your work to some other space.
>
> The term "Full Range" RGB is not very meaningful except to imply that the 
> data is not using "video" levels.
>
> Bob
> ======================================
> Bob Friesenhahn
> bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/ 




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