On 27/11/14 13:37, Stephen wrote:
> How about:
> Zebedee is on the sex register?
> Florence dobbed him in.
> 
> (That should keep you awake at nights.) :-P
> 

I'm getting increasingly worried about your mental state, young man. ;-)

Now it's time for me to head over the river to attend a pointless meeting.

John
-- 
Protect the Earth
It was not given to you by your parents
You hold it in trust for your children

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On 27/11/2014 13:52, Doctor John wrote:
> I'm getting increasingly worried about your mental state, young man.;-)
>


> Now it's time for me to head over the river to attend a pointless meeting.

The stews, again?

-- 

Regards
     Stephen

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Am 26.11.2014 16:34, schrieb Stephen:
> On 26/11/2014 15:02, Thomas de Groot wrote:
>> What is a pallet-based transparency? The term is unfamiliar to me.
>
> Not surprised. I made it up.
>
>  From the top of my head:
> It is an index of colours used in the image. In Pov we can set the
> transparency and filter values in the image_map definition. Each entry
> in the index can be set to a transparency, individually. I think that
> pallet based images are limited to 8 bit images.
> So in a cloud map each grey could have a different level of transparency.
>
> rgb -> rgbft

Actually, with palette-based images you are limited to 1 bit of 
transparency: On or off. Because there's just one special colour among 
the 256 that denotes a transparent pixel.

Images with alpha channel (usually png) typically give you 8 bit of 
transparency information. If you need more, you can opt for one of the 
following:

A) 16-bit png images with alpha channel.

B) pigment_map, using the image's greyscale value to choose between an 
opaque and a transparent pigment. (Make sure to set a proper "gamma" 
parameter!). However, this will typically give you not much more than 8 
bit either, so you'll want to go for 16-bit images anyway.

C) high dynamic range images; OpenEXR can support an alpha channel, 
alternatively you can use pigment_map as described above. However, near 
100% its precision is a good deal less than that of 16-bit images 
(comparable to 12-bit images; Radiance HDR is even worse).

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Am 26.11.2014 20:16, schrieb Stephen:
> On 26/11/2014 18:54, Ive wrote:
>>
>> With some scattering media atmosphere it gives something like this:
>> http://news.povray.org/povray.binaries.images/thread/<4a056976@news.povray.org>
>>
>>
> Before I look at your suggestions. The above link only goes to the index.

The plain text is fine, it's just the link behind it that's broken.

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On 28/11/2014 12:24, clipka wrote:
> Actually, with palette-based images you are limited to 1 bit of
> transparency: On or off. Because there's just one special colour among
> the 256 that denotes a transparent pixel.
>
> Images with alpha channel (usually png) typically give you 8 bit of
> transparency information. If you need more, you can opt for one of the
> following:
>
> A) 16-bit png images with alpha channel.
>
> B) pigment_map, using the image's greyscale value to choose between an
> opaque and a transparent pigment. (Make sure to set a proper "gamma"
> parameter!). However, this will typically give you not much more than 8
> bit either, so you'll want to go for 16-bit images anyway.
>
> C) high dynamic range images; OpenEXR can support an alpha channel,
> alternatively you can use pigment_map as described above. However, near
> 100% its precision is a good deal less than that of 16-bit images
> (comparable to 12-bit images; Radiance HDR is even worse).

Thanks Clipka, I thought that I was finished with this. But what you've 
written need digesting. :-)


I must find another editor I've been using PaintShop Pro out of "it's 
good enough and I've always used it". What you can do with pallets and 
Alpha is basic.

Interestingly the 24 bit Tiff Cloud Map, I downloaded from Blue Marble. 
Has only 253 different colours.

-- 

Regards
     Stephen

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Thomas de Groot <tho### [at] degrootorg> wrote:
> On 27-11-2014 11:55, Stephen wrote:
>
> > Be careful. Once you start looking at old scenes. You will find
> > something else that wants improving. Never ending.
> > I noticed that some of my earth maps go back to 98 (when I downloaded
> > them) and the ones I normally use are from 2008. So I downloaded some of
> > the Blue Marble ones. Now the Nautilus model does not fit in with the
> > Earth . I will need to rework its textures.
> >
> >
> I know. It is a difficult to resist temptation.
>
> Thomas

Having fun and "resting" my brain scrolling through
https://www.google.co.uk/search?q=site:news.povray.org&tbm=isch

and I came across this:

http://news.povray.org/povray.binaries.images/attachment/%3C43e348c8%40news.povray.org%3E/Alien%20Cliff.jpg?ttop=284089
&toff=1600

Which instantly meshed with a scene in the book I'm (finally) reading - "Against
All Things Ending" by Stephen Donaldson, where Linden Avery beholds Landsdrop:

"And she caught sight of Landsdrop. Grey in the depthless sunlight, it loomed
two thousand feet and more above her own elevation: a blunt rampart smoothed by
the ages until it appeared almost blank; too sheer to scale. But she knew from
old experience as well as from tales that Landsdrop was more accessible than it
looked. There were trails of all kinds up and down the precipice, although she
could not descry them at this distance. Ignoring the impatience of the Ranyhyn,
Linden studied the vista. Almost directly to the west, a thin string of water
fell as though it had been tossed over the rim by a negligent hand. Dull against
the dim stone, like a strand of tarnished silver, it dropped in stages, shifting
from side to side as its plunge encountered obstacles, and casting fine hints of
spray into the etiolated sunshine."

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On 27/11/14 14:10, Stephen wrote:
> 
> The stews, again?
> 

How well you know me, young man :-p

John
-- 
Protect the Earth
It was not given to you by your parents
You hold it in trust for your children

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On 28/11/2014 20:58, Doctor John wrote:
> On 27/11/14 14:10, Stephen wrote:
>>
>> The stews, again?
>>
>
> How well you know me, young man :-p
>

I didn't until you admitted it. :-P


-- 

Regards
     Stephen

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On 28-11-2014 20:16, Bald Eagle wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> On 27-11-2014 11:55, Stephen wrote:
>>
>>> Be careful. Once you start looking at old scenes. You will find
>>> something else that wants improving. Never ending.
>>> I noticed that some of my earth maps go back to 98 (when I downloaded
>>> them) and the ones I normally use are from 2008. So I downloaded some of
>>> the Blue Marble ones. Now the Nautilus model does not fit in with the
>>> Earth . I will need to rework its textures.
>>>
>>>
>> I know. It is a difficult to resist temptation.
>>
>> Thomas
>
> Having fun and "resting" my brain scrolling through
> https://www.google.co.uk/search?q=site:news.povray.org&tbm=isch
>
> and I came across this:
>
>
http://news.povray.org/povray.binaries.images/attachment/%3C43e348c8%40news.povray.org%3E/Alien%20Cliff.jpg?ttop=284089
> &toff=1600
>
> Which instantly meshed with a scene in the book I'm (finally) reading - "Against
> All Things Ending" by Stephen Donaldson, where Linden Avery beholds Landsdrop:
>
> "And she caught sight of Landsdrop. Grey in the depthless sunlight, it loomed
> two thousand feet and more above her own elevation: a blunt rampart smoothed by
> the ages until it appeared almost blank; too sheer to scale. But she knew from
> old experience as well as from tales that Landsdrop was more accessible than it
> looked. There were trails of all kinds up and down the precipice, although she
> could not descry them at this distance. Ignoring the impatience of the Ranyhyn,
> Linden studied the vista. Almost directly to the west, a thin string of water
> fell as though it had been tossed over the rim by a negligent hand. Dull against
> the dim stone, like a strand of tarnished silver, it dropped in stages, shifting
> from side to side as its plunge encountered obstacles, and casting fine hints of
> spray into the etiolated sunshine."
>

And yet, it was not inspired by Donaldson... :-) It was by another SF 
world: Mount Lookitthat on Plateau, imagined by Larry Niven. The concept 
then drifted slowly away from there to the present image.

Thomas

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On 28-11-2014 13:24, clipka wrote:
> A) 16-bit png images with alpha channel.
>

Which reminds me: Using IC, how can one convert an 8-bit png into a 
16-bit png? I suppose the image needs to be resampled but with what 
settings?

Thomas

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