Hi!

Thank you for your help.

I read your answers for my question. Now, I realize that moe pixels lead to
high resolution at the same size image. Now, our images from POV-RAY are 72
pixels/inch. Can I increase 300 pixels/inch at the same size images? If
not, could you give me idea to increase resolution? I want to generete
publication quality images with POV-RAY.

In addition, after running the program, images are automatically saved to
'bmp FILE'. Can I save it as a compressed file (i.e. jpg) within POV-RAY
program?

Thank you again

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James <hy5### [at] hanmailnet> wrote:
> Now, our images from POV-RAY are 72
> pixels/inch.

  That's in no way POV-Ray's fault. It's just the program you are using
(photoshop perhaps?) which by default prints things at 72 dpi. Just tell
that program to print at a higher dpi.

> Can I increase 300 pixels/inch at the same size images?

  Well, if you want to keep the same physical size (in inches) when
printing, you need to render the image at a higher pixel resolution,
obviously.

  I assume you are using the Windows version of POV-Ray. In the upper
left corner there's a drop-down menu with some preset resolutions.
Since those are probably not high enough, you can set your own resolution
in the text-field at the right of that drop-down menu. For example, if
you wanted to render at a resolution of 4000x3000, write this to that
textfield:

-w4000 -h3000 +a

(The "+a" turns basic antialiasing on, which I assume you want.)

> In addition, after running the program, images are automatically saved to
> 'bmp FILE'. Can I save it as a compressed file (i.e. jpg) within POV-RAY
> program?

  JPEG is not supported as an output format (only as input) for a pretty
obvious reason: It wouldn't be nice to have a 4-day render only to see
then that your JPEG settings were too low and the image looks like crap.

  A good lossless alternative to bmp is using png, which you can set
by adding "+fn" to the end of that textfield, like this:

-w4000 -h3000 +a +fn

  You can also add "+fn" to the end of the main povray.ini file so that
all images are always saved in the png format and you don't have to
specify it every time (in the tools menu there's an entry to edit povray.ini).

-- 
                                                          - Warp

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James wrote:
> Hi!
> 
> Thank you for your help.
> 
> I read your answers for my question. Now, I realize that moe pixels lead to
> high resolution at the same size image. Now, our images from POV-RAY are 72
> pixels/inch. Can I increase 300 pixels/inch at the same size images? If
> not, could you give me idea to increase resolution? I want to generete
> publication quality images with POV-RAY.

Have you read the thread you were pointed to?  From what you wrote it 
seems you have not.

> In addition, after running the program, images are automatically saved to
> 'bmp FILE'. Can I save it as a compressed file

Yes, just use '+fn'.

> (i.e. jpg) within POV-RAY
> program?

No.

Christoph

-- 
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 31 Oct. 2005)
MegaPOV with mechanics simulation: http://megapov.inetart.net/

Post a reply to this message

Christoph Hormann <chr### [at] gmxde> wrote:
> James wrote:
> > Hi!
> >
> > Thank you for your help.
> >
> > I read your answers for my question. Now, I realize that moe pixels lead to
> > high resolution at the same size image. Now, our images from POV-RAY are 72
> > pixels/inch. Can I increase 300 pixels/inch at the same size images? If
> > not, could you give me idea to increase resolution? I want to generete
> > publication quality images with POV-RAY.
>
> Have you read the thread you were pointed to?  From what you wrote it
> seems you have not.
>
> > In addition, after running the program, images are automatically saved to
> > 'bmp FILE'. Can I save it as a compressed file
>
> Yes, just use '+fn'.
>
> > (i.e. jpg) within POV-RAY
> > program?
>
> No.
>
> Christoph
>
> --
> POV-Ray tutorials, include files, Landscape of the week:
> http://www.imagico.de/ (Last updated 31 Oct. 2005)
> MegaPOV with mechanics simulation: http://megapov.inetart.net/

Thank you very much

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Warp wrote:
> James <hy5### [at] hanmailnet> wrote:
> 
>>Now, our images from POV-RAY are 72
>>pixels/inch.
> 
> 
>   That's in no way POV-Ray's fault. It's just the program you are using
> (photoshop perhaps?) which by default prints things at 72 dpi. Just tell
> that program to print at a higher dpi.
>
Besides that, the dpi (or ppi, same thing) that's stored in an image 
file is nothing more than a data value stored in the file header.  It 
has NO effect on the image data itself.  What's more, this value can be 
changed arbitrarily by most graphic editing software -- sometimes it can 
be obscure to find, but it's generally there someplace.  In Paint Shop 
Pro for example, it's in the resize dialog box.  But in reality this 
stored dpi value IS TOTALLY IRRELEVANT -- forget about it.  The key 
point (as everyone has been telling you) is the image size in pixel 
dimensions.

If you are aiming at a specific size/quality, start from there and work 
backwards, the math is straight-forward.  For an arbitrary example, say 
you want a 20" x 30" poster.  If it's to be printed at 100 dpi it has to 
be 2000 x 3000 pixels.  300 dpi would be 6000 x 9000 pixels.  600 dpi 
would be 12000 x 18000.  And so on...  (Be prepared for loooooong 
renders -- quality takes time.)

Now, the 72 dpi value you see all the time is used simply as an average 
video screen resolution.  Naturally, the real ppi value varies with the 
screen size and resolution, but 72 is used as a typical average.  That's 
why most graphics software uses this as a default dpi value.  But again, 
it has no real significance.  When an image is displayed on a video 
screen, the stored dpi value is completely ignored -- after all, the 
screen has a fixed resolution and can't use anything else.  OTOH, 
printers can, and the printing software can adjust the output for 
different dpi resolutions.  It might start with the stored dpi value, 
but it can adjust it from there, so it's still basically irrelevant.

      -=- Larry -=-

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