On 7 Mar 2004 12:57:26 -0500, ingo <ing### [at] tagpovrayorg> wrote:

>in news:d1bm40hmv75jeiuj3cp3v1382aon91bpk9@4ax.com IMBJR wrote:
>
>> 2. Representation of 16-bit colour depth. Very good, since POV-Ray is
>> capable of producing 16-bit colour depth images. The downside is the
>> receiving machine's capabilites in regards to this, but at least the
>> 16-bit intent is preserved.
>
>Just wondering, what does Irfanview do to 6 bit jpeg200 images. Does it 
>show it as a 16 bit image or does it downsample it? Most software does 
>for 16 bit png's.

Wish I knew. I've never actually tested this. It would be a pity if
the majority downsampled. Dithering at least would be a more honest
attempt at rendering the intent of the format.

>
>In general, 16 bit images have their purposes, but i.m.o. showing images 
>on monitors is not one of them. The main advantage of 16 bit images over 
>8 bit images is the extended contrast range. A contrast range that a crt 
>can't show and lcd / plasma screens are even worse in this regard.

I still maintain that they would help in reducing gradient-banding -
but that really does depend on the end viewer. At least the intent is
there though. If it is there then perhaps at a future date, the image
can be better viewed. Mind, this might not be a very good argument
because, let's face it, lossy compression is already throwing things
away.

>
>16 bit images are nice for photographic printing on slide material as 
>they can show a bigger contrast range. 16 bit images are nice as an 
>intermediate format between rendering and showing on screen as an 8 bit 
>image. It gives you the possibility to control contrast a lot better by 
>converting to 8 / 12 / whatever bit images using a controlable transfer 
>function. In this regard, search for some of Kari Kivisalo's work on 
>this newsserver.
>
>If the intent is preservation of the original, I would not use any lossy 
>compression.

Indeed. I'm beginning to suspect that this might actually be the case.

>
>'Pushing' towards a "standard" or even a new format in these greedy 
>times, knowing that there are patent issues i.m.o. is a folly of the 
>jpeg committee. 
>
>In general, I don't care in what format an image or animation is posted. 
>If I can't see it, so be it.

I agree.

>
>Ingo

--------------------------------
My First Subgenius Picture Book:
http://www.imbjr.com

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