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On 5-3-2018 21:51, Kenneth wrote:
> Thomas de Groot <tho### [at] degroot org> wrote:
>
>>>
>>> I shall make a small test scene. A way for me to remember stuff.
>>>
>>
>> Like this. Left, image gamma is 1.0; right, image gamma is 2.2.
>>
>
> Nice! And you picked a good pattern to show it off.
>
> The real *fun* begins when you take a height_field image (made elsewhere) and
> *combine* it with a procedural pigment or pattern-- both of which can be
> gamma-bent. It's a bit more complicated to code, but I was working up an example
> anyway, and will post in a new thread. (BTW, some other interesting effects can
> be gotten by making the gamma *less than* 1.0.)
>
Been there done that ;-)
Even better if you use the image and the pattern within functions and
combine those.
--
Thomas
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On 5-3-2018 21:36, Kenneth wrote:
> "Norbert Kern" <nor### [at] t-onlinede> wrote:
>> Stephen <mca### [at] aolcom> wrote:
>>
>>> Has anyone tried to produce a solarisation effect?
>>
>> Hi,
>> with a simple approach I got this image - here is the code
>>
> Brilliant! I actually didn't think it was possible.
>
*everything* is possible in POV-Ray! ;-)
--
Thomas
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Am 06.03.2018 um 00:02 schrieb Kenneth:
> "Kenneth" <kdw### [at] gmailcom> wrote:
>> (There's also a HF difference
>> between images SAVED at different gamma values, for the same reason-- 1.0 being
>> a linear slope, 2.2 being more of a curve.)
>
> Uh, I'm not so sure about that now. I made a test scene a couple of weeks ago
> that showed this. (Or so I thought.) Now, a newer test scene shows no
> difference-- producing the same 'linear' height_field slopes no matter what
> gamma the images are saved at (with either JPEG *or* PNG image files.) But then
> again, I'm using my older wonky Photoshop 5 to make and save the original
> images, which can't be completely trusted as far as gamma goes. Hmm, a mystery.
By default, when using images in a height_field, POV-Ray presumes that
the image data is to be taken linearly no matter what gamma the file
claims to match, e.g. in an 8-bit image a data value of 240 will always
be interpreted as a height of 240/255, even if the file claims to be
saved for a display gamma of 2.2.
So if you just create an image in Photoshop and /assign/ a particular
gamma to it later, there will be no difference as the image data will
not change. You'd need to /convert/ the image from one gamma to another
to see an effect.
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clipka <ano### [at] anonymousorg> wrote:
> Am 06.03.2018 um 00:02 schrieb Kenneth:
> > Now, a newer test scene shows no
> > difference-- producing the same 'linear' height_field slopes no matter what
> > gamma the images are saved at...
>
> By default, when using images in a height_field, POV-Ray presumes that
> the image data is to be taken linearly no matter what gamma the file
> claims to match, e.g. in an 8-bit image a data value of 240 will always
> be interpreted as a height of 240/255, even if the file claims to be
> saved for a display gamma of 2.2.
>
> So if you just create an image in Photoshop and /assign/ a particular
> gamma to it later, there will be no difference as the image data will
> not change. You'd need to /convert/ the image from one gamma to another
> to see an effect.
Thanks. My older test scene was also more complicated-- using a HF-image gamma
*and* a pigment_map with a blend mode/blend gamma. That combination probably
confused the result for me.
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Hi(gh)!
On 02.03.2018 16:27, And wrote:
> #declare p_modify1 =
> pigment{
> pigment_pattern{p_original}
> pigment_map{
> #for(i,0,255)
> [i/255,
> bumps
> scale 1/input_wide_res
> scale 4.8
> rotate <0,0,20>
> color_map{
> [0.2+0.6*(1-pow(i/255,1/3)) rgbt<0,0,0,0.1>]
> [0.2+0.6*(1-pow(i/255,1/3)) rgbt<0,0,0,0.9>]
> }
> ]
> #end
> }
> }
Very interesting! May I use your p_modify versions for my video
experiments on YouTube
(https://www.youtube.com/channel/UCFgDHkMGDuOkiSnc6w6eUWg)? To those who
modificated it, I ask the same question...
See you in Khyberspace!
Yadgar
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> Very interesting! May I use your p_modify versions for my video
> experiments on YouTube
> (https://www.youtube.com/channel/UCFgDHkMGDuOkiSnc6w6eUWg)? To those who
> modificated it, I ask the same question...
>
I am working on some general changes of the code, which I shall post
later. You have my full permission, but And is the real owner/originator.
--
Thomas
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Yadgar_Bleimann?= <yaz### [at] gmxde> wrote:
> Very interesting! May I use your p_modify versions for my video
> experiments on YouTube
> (https://www.youtube.com/channel/UCFgDHkMGDuOkiSnc6w6eUWg)? To those who
> modificated it, I ask the same question...
>
> See you in Khyberspace!
>
> Yadgar
Hi,
of course
Norbert
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On 5-3-2018 17:52, Stephen wrote:
> On 05/03/2018 16:50, Stephen wrote:
>>
>> Oo! shiny. I like.
>>
>> You are on a roll, Norbert. :-)
>
> It looks good as a negative, too (also).
>
Absolutely! This one is inversed.
--
Thomas
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Attachments:
Download 'nk_solarisation_invert.jpg' (287 KB)
Preview of image 'nk_solarisation_invert.jpg'
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On 8-3-2018 13:33, Thomas de Groot wrote:
> On 5-3-2018 17:52, Stephen wrote:
>> On 05/03/2018 16:50, Stephen wrote:
>>>
>>> Oo! shiny. I like.
>>>
>>> You are on a roll, Norbert. :-)
>>
>> It looks good as a negative, too (also).
>>
>
> Absolutely! This one is inversed.
>
Want to know where this is? Go to: 52 degrees 53 minutes 46.25 seconds
North, and 6 degrees 15 minutes 46.11 seconds East.
--
Thomas
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On 08/03/2018 12:33, Thomas de Groot wrote:
> On 5-3-2018 17:52, Stephen wrote:
>> On 05/03/2018 16:50, Stephen wrote:
>>>
>>> Oo! shiny. I like.
>>>
>>> You are on a roll, Norbert. :-)
>>
>> It looks good as a negative, too (also).
>>
>
> Absolutely! This one is inversed.
>
Me like. :-)
--
Regards
Stephen
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