Op 13/02/2021 om 21:09 schreef Kenneth:
> Cousin Ricky <ric### [at] yahoocom> wrote:
>>
>> This is exactly what versions 3.5 and earlier did, and when I compare it
>> to the newer post-clipped anti-aliasing, certain effects, such as
>> highlights with blurred reflection, look pretty limp.  There is a
>> trade-off between good hyper-white effects and good anti-aliasing, and
>> on balance, I'd have to say I prefer the latter.  It is easier to post
>> process hyper-white effects than to boost an image whose contrasts have
>> been compromised by averaging out its brightest elements after they've
>> *already* been clipped.
>>
> 
> Thanks to you and William for the in-depth analysis. Looks like this subject is
> an old one ;-) I'm still absorbing the details.
> 
> I guess I'm not yet fully understanding the visual flaws or contrast differences
> produced by 'pre-clipping' extra-bright pixels vs. 'post-clipping.' From your
> images, the differences seem to be very subtle(?)
> 
> I just downloaded sbenge's 'luminous bloom' post-processing tool (thanks for the
> link) but haven't tried using it yet, or looking over the code. From his older
> posted images, the bloom effect appears to affect the entire image, rather than
> just the too-bright pixels. Maybe I'm mistaken? And does it work with a typical
> pre-rendered low-dynamic-range image, or just with some kind of HDR-rendering
> scheme? Sorry if these are naive questions; his older comments deal solely with
> HDR, AFAIK. (I did a newsgroup search for 'luminous bloom', but could not find
> much info regarding LDR renders.)
> 

When I recently used Sam's Bloom (version 6 btw) I changed a couple of 
things:
- added: #version 3.8;
- changed the default to: #default{finish{emission 1}} (instead of 
#default{finish{ambient 1}}
- changed the image_pw to 1.0 (all images use gamma 1.0 now, not only 
HDR like in Sam's time)

This I used for the blooming A Quiet Lane scene; with some extra 
tweaking of course, but those are the fundamental changes.

-- 
Thomas

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