Re: Lab in Photoshop
Re: Lab in Photoshop
- Subject: Re: Lab in Photoshop
- From: "Bruce J. Lindbloom" <email@hidden>
- Date: Mon, 15 Jul 2002 10:03:36 -0500
Bruce Fraser wrote:
>
Quantization errors converting to Lab vary in severity depending on
>
the source space, but typically you'll lose somewhere around 25-45 of
>
the available 256 levels. It's not automatically a bad thing, just a
>
trade-off you need to weigh before you convert to Lab for a
>
particular edit that's easier in that mode.
A very good explanation. The actual number of levels lost to quantization
may be determined for many cases using a Levels Calculator I have written
(see "Levels Calculator" on the "Color" page of
http://www.brucelindbloom.com). For example, Adobe 1998 (gamma = 2.2) has
256 available levels for neutrals. Converting to 8-bit Lab reduces these 256
unique levels down to 234, a loss of 22 levels. Starting from ProPhoto
(gamma = 1.8), you end up with only 225, a loss of 31 levels.
I agree with Bruce that this is not necessarily a bad thing, but it is
always good to understand principles behind the trade-offs you are making.
--
Bruce J. Lindbloom
email@hidden
http://www.brucelindbloom.com
_______________________________________________
colorsync-users mailing list | email@hidden
Help/Unsubscribe/Archives:
http://www.lists.apple.com/mailman/listinfo/colorsync-users
Do not post admin requests to the list. They will be ignored.