Google| Subject | Re: Is RGB to Lab lossy? - was(Re: Lenses and sharpening) |
| From | PeterN |
| Date | 10/06/2014 03:52 (10/05/2014 21:52) |
| Message-ID | <m0sskh02g2i@news1.newsguy.com> |
| Client | |
| Newsgroups | rec.photo.digital |
| Follows | nospam |
| Followups | nospam (1d, 19h & 34m) > PeterN |
On 10/5/2014 9:05 PM, nospam wrote:
nospamYes it can be done in RGB, but with a lot more effort. Take a simple example stock photo and change the color in RGB, and then make the same color change in LAB.
In article <s7h13a1fccm418skpdorc8ea5jvm4gm40j@4ax.com>, Eric Stevens <eric.stevens@sum.co.nz>wrote:nospamEric StevensEric Stevensnospam
I couldn't see the difference at all, but then I didn't want to push the screen with excessive brightness. Instead I relied on the subtraction and the histogram to find the differences, which were almost zero.
'almost zero' is not zero.
you are actually proving my point.Eric Stevensnospam
nospam has backed off considerably from his original views but I expect that won't stop him from trumpeting them again in the future.
i have *not* done any such thing. stop lying and twisting what i say.
i have *always* said it's not lossless and it is not.
There is nothing you do in image processing which is not lossless.
straw man.Eric Stevensnospam
For some reason the conversion of RGB -->Lab has been particularly singled out for criticism in this respect.
it's a bad workflow because what can be done with an rgb->lab-rgb conversion can be done *without* the conversion and with better results.
Or, simply increase color saturation n RGB and make the same change in LAB. All yo do is sout questionable theory. Show some real life proof.
-- PeterNnospamthis is a fact, no matter how much you or anyone else say otherwise.Eric Stevens
It's as lossless as anything else you can do.
it's more lossy than not doing the conversions.
09/13/2014-
