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A real bad way:
Use rgb single floats, force 8-bit display (under Options in Windows
version menu anyway) and do a screen capture.
Yuck! Never mind.
Kyle wrote:
>
> Hi everyone. I have a quick question. Is there any way to have POV-Ray
> render in black and white? I'm thinking about submitting an IRTC image
> in black and white, but since post-processing is not allowed, I don't
> see a good way to do it. Is there some setting in POV-Ray for this? Of
> course, I can just give all the objects a greyish color but I don't
> think that would come out very nicely. Well, if anyone has a suggestion
> I'd be very grateful to hear it.
>
> Kyle
--
omniVERSE: beyond the universe
http://members.aol.com/inversez/POVring.htm
mailto:inv### [at] aol com?PoV
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On Sat, 13 Mar 1999 06:44:16 +1030, PoD <pod### [at] merlinnetau> wrote:
>I'm pretty sure that reasonable post processing is allowed in the IRTC.
>I recall reading that processing which affects all pixels similarly is
>acceptable, ie. 'if you wouldn't be willing to do it to every frame of
>an animation, it's probably not acceptable' so I'd just load the image
>into a paint program and grey scale it.
Not so, I'm afraid. That would definitely be illegal postprocessing.
The intent of the rule and the somewhat poor example you quote has
been clarified in irtc-l. The desired situation is no postprocessing
at all. About the only things generally considered acceptable
postprocessing are: adding copyright/sig, jpeg conversion. resizing,
gamma/brightness correction, (this causes some controversy) stitching
together an image rendered in pieces and (this is even more
controversial) cropping in certain circumstances. Many people go to
great extremes to avoid even these things where possible.
Jerry Anning
clem "at" dhol "dot" com
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"Margus Ramst" <mar### [at] peakeduee> writes:
> hf_gray_16 generates 16 bit grayscale images, every pixel value should be
> considered a 2-byte "word". This is non-standard; graphics packages will not
> translate the image correctly as a grayscale bitmap. Have you looked what a
> heightfield tga looks like in, say, PSP? It's red-green.
Sure. But, as was said before, save as PNG and you'll get a sixteen bit
per pixel *black and white* image. Not a red-green one.
--
Roland Mas
Sauvez une souris, mangez votre chat.
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Jerry Anning wrote in message <36e98f24.23757454@news.povray.org>...
>On Sat, 13 Mar 1999 06:44:16 +1030, PoD <pod### [at] merlinnetau> wrote:
>
>>I'm pretty sure that reasonable post processing is allowed in the IRTC.
>>I recall reading that processing which affects all pixels similarly is
>>acceptable, ie. 'if you wouldn't be willing to do it to every frame of
>>an animation, it's probably not acceptable' so I'd just load the image
>>into a paint program and grey scale it.
>
>Not so, I'm afraid. That would definitely be illegal postprocessing.
>The intent of the rule and the somewhat poor example you quote has
>been clarified in irtc-l. The desired situation is no postprocessing
>at all. About the only things generally considered acceptable
>postprocessing are: adding copyright/sig, jpeg conversion. resizing,
>gamma/brightness correction, (this causes some controversy) stitching
>together an image rendered in pieces and (this is even more
>controversial) cropping in certain circumstances. Many people go to
>great extremes to avoid even these things where possible.
>
>Jerry Anning
>clem "at" dhol "dot" com
While I haven't had a go at IRTC (yet), I have read the rules. It seems to
me that it is quite acceptable to use a graphics program to convert an image
from one "file format" to another, for axample, TGA to JPG, for posting. How
is it different if I open my 16-bit grayscale image and save it as a 24-bit
jpeg? The program recognises that the image is gray, not colour and behaves
appropriately.
Comments?
Gordon
<gbe### [at] birdcameroncomau>
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Gordon wrote:
>
> Jerry Anning wrote in message <36e98f24.23757454@news.povray.org>...
> >On Sat, 13 Mar 1999 06:44:16 +1030, PoD <pod### [at] merlinnetau> wrote:
> >
> >>I'm pretty sure that reasonable post processing is allowed in the IRTC.
> >>I recall reading that processing which affects all pixels similarly is
> >>acceptable, ie. 'if you wouldn't be willing to do it to every frame of
> >>an animation, it's probably not acceptable' so I'd just load the image
> >>into a paint program and grey scale it.
> >
> >Not so, I'm afraid. That would definitely be illegal postprocessing.
> >The intent of the rule and the somewhat poor example you quote has
> >been clarified in irtc-l. The desired situation is no postprocessing
> >at all. About the only things generally considered acceptable
> >postprocessing are: adding copyright/sig, jpeg conversion. resizing,
> >gamma/brightness correction, (this causes some controversy) stitching
> >together an image rendered in pieces and (this is even more
> >controversial) cropping in certain circumstances. Many people go to
> >great extremes to avoid even these things where possible.
> >
> >Jerry Anning
> >clem "at" dhol "dot" com
>
> While I haven't had a go at IRTC (yet), I have read the rules. It seems to
> me that it is quite acceptable to use a graphics program to convert an image
> from one "file format" to another, for axample, TGA to JPG, for posting. How
> is it different if I open my 16-bit grayscale image and save it as a 24-bit
> jpeg? The program recognises that the image is gray, not colour and behaves
> appropriately.
>
> Comments?
>
> Gordon
> <gbe### [at] birdcameroncomau>
I think in this case it is more an issue of taking a 16m color image
and converting it to 256 shades of gray that would be in non compliance
with the rules. If you are silly enough to take make a rendering in Pov's
16bit greyscale, convert it, and then submit it to the competition you
might just get sympathy votes for being so stupid.
--
Ken Tyler
mailto://tylereng@pacbell.net
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Gee!!! I've used that thing HUNDREDS of times and yet I've totally
forgotten it existed!!! he he he
And of course, that's right, you'd think that after studying physics for 6
months and a huge chapter on colour wavelengths I would have realised that
you can't just use an algorithm to convert the pigments in your scene
because then the lights won't react in the right way!!!
Maybe I should actually consider THINKING before I post!!!
--
Lance.
---
For the latest 3D Studio MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone
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OK, I've got an idea but I can't remember if it's possible or not (it's been
a while since I've used POV-Ray).
Can you render the image in normal colour, then SOMEHOW work out a way of
rendering the two images over each other with negative colour indices? That
way the resulting image would be black and white...
The only problem is, how do you get an inverse of the picture without doing
image editing? Is there a way to multiply the image_map pigments by -1?
This would solve all the problems, if it were possible. Any ideas?
Of course the other way (WHICH WOULD TAKE MUCH LONGER!!!) is to write a
macro which reads from the Targa file and creates an array of boxes with the
black and white colour conversions for each pixel so that when rendered you
would have the image again... You'd have to turn anti-aliasing off...
--
Lance.
---
For the latest 3D Studio MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone
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Lance Birch wrote:
>
> OK, I've got an idea but I can't remember if it's possible or not (it's been
> a while since I've used POV-Ray).
>
> Can you render the image in normal colour, then SOMEHOW work out a way of
> rendering the two images over each other with negative colour indices? That
> way the resulting image would be black and white...
>
> The only problem is, how do you get an inverse of the picture without doing
> image editing? Is there a way to multiply the image_map pigments by -1?
>
> This would solve all the problems, if it were possible. Any ideas?
>
> Of course the other way (WHICH WOULD TAKE MUCH LONGER!!!) is to write a
> macro which reads from the Targa file and creates an array of boxes with the
> black and white colour conversions for each pixel so that when rendered you
> would have the image again... You'd have to turn anti-aliasing off...
>
> --
> Lance.
I don't know why anybody would go through the trouble. It is very easy
to make grey scale images without resorting to a bunch of tricks or having
to use post processing techniques. Grey/Gray is an easy color to specifiy
in Pov and will work with any pigment pattertn and texture types. It really
is not that difficult to choose the right colors. I have more trouble getting
the right shades of colors than I do shades of grey and I'm pretty good at
color control.
--
Ken Tyler
mailto://tylereng@pacbell.net
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Kyle wrote:
>
> Hi everyone. I have a quick question. Is there any way to have POV-Ray
> render in black and white? I'm thinking about submitting an IRTC image
> in black and white, but since post-processing is not allowed, I don't
> see a good way to do it. Is there some setting in POV-Ray for this? Of
> course, I can just give all the objects a greyish color but I don't
> think that would come out very nicely. Well, if anyone has a suggestion
> I'd be very grateful to hear it.
>
> Kyle
See what a mess you started here Kyle ?
One other possibility that the folks in this crowd can grind donw the
merit of is using a reflection vector with every object in the scene.
If you use reflection <0.5,0.5,0.5> the color reflected off the object
will by a 50% gray and the rest will be filtered out. How well this
would work is untested and I don't know if you can stack reflection
vectors on top of each other. If you can it might be possible to make
a global reflection for the whole scene. Or - maybe not !
--
Ken Tyler
mailto://tylereng@pacbell.net
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NO NO NO!!! It DOESN'T WORK!!!
Ken, have you tried a red light source on a red and white sphere lately?
I'd like you to try making that in greyscale... This is the point I missed
in my first post and I really should have pointed it out earlier. Remember,
because the light sources can be different colours, the surfaces of objects
will react in different ways. Like a blue shere will look different under
red light... and another coloured sphere under the same light will look
different again. If you convert the lights to just intenisties (which is
what you're suggesting) the surfaces won't react differently so the objects
won't appear realistic.
Remember, the problem lies in the wavelengths.
--
Lance.
---
For the latest 3D Studio MAX plug-ins, images and much more, go to:
The Zone - http://come.to/the.zone
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