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26 Nov 2024 02:00:38 EST (-0500)
  resolution question (Message 1 to 8 of 8)  
From: Stephen
Subject: resolution question
Date: 24 Dec 2004 01:18:19
Message: <41cbb4ab$1@news.povray.org>
I just ** hope** this isn't covered in the doc'n somewhere, but since I
can't find the answer to my question, I'll ask:

What is the native resolution of POVRay - not the rendering size, but the
number of dots per inch?  One chunk of SW that I have says 96dpi and another
implies 76ish about some rendered images.

My standard output type is BMP (oh, well) but I typically like JPGs and can
work with other file types. My interest is in getting the best possible
detailed rendering and then if my printer or scaling wants to muddle with
that, then so be it.

Any way to get higher resolutions?

-- 

Stephen

signup42atshawdotca


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From: Neil Kolban
Subject: Re: resolution question
Date: 24 Dec 2004 01:35:56
Message: <41cbb8cc$1@news.povray.org>
Stephen,
Pretty much a newbie myself.  I don't think there is a concept of dpi with
POVRay.  Instead, the result of a render is an image file of so many pixels
wide and so many pixels high.  There is no more information in the file than
that.

Lets say, just for argument, that your printer can print 200 dpi and you
want to print on a 6" x 4" paper, then my math seems to say that your
optimal image size would be 1200x800 pixels.  Within POVRay, you can declare
the size of the output image to be anything you want.

Neil


"Stephen" <sig### [at] shawca> wrote in message
news:41cbb4ab$1@news.povray.org...
> I just ** hope** this isn't covered in the doc'n somewhere, but since I
> can't find the answer to my question, I'll ask:
>
> What is the native resolution of POVRay - not the rendering size, but the
> number of dots per inch?  One chunk of SW that I have says 96dpi and
another
> implies 76ish about some rendered images.
>
> My standard output type is BMP (oh, well) but I typically like JPGs and
can
> work with other file types. My interest is in getting the best possible
> detailed rendering and then if my printer or scaling wants to muddle with
> that, then so be it.
>
> Any way to get higher resolutions?
>
> -- 
>
> Stephen
>
> signup42atshawdotca
>
>


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From: Mike Williams
Subject: Re: resolution question
Date: 24 Dec 2004 03:30:20
Message: <MqxAFBAxN9yBFwcy@econym.demon.co.uk>
Wasn't it Stephen who wrote:
>I just ** hope** this isn't covered in the doc'n somewhere, but since I
>can't find the answer to my question, I'll ask:
>
>What is the native resolution of POVRay - not the rendering size, but the
>number of dots per inch?  One chunk of SW that I have says 96dpi and another
>implies 76ish about some rendered images.
>
>My standard output type is BMP (oh, well) but I typically like JPGs and can
>work with other file types. My interest is in getting the best possible
>detailed rendering and then if my printer or scaling wants to muddle with
>that, then so be it.
>
>Any way to get higher resolutions?

POV doesn't have a native resolution. It never writes the optional
resolution data field to the files that it outputs. (Some image formats,
such as Targa, don't support the saving of a resolution value).

The 96ppi and 76ppi that you see are the default values used by your
software when they open an image file which doesn't contain a value for
the resolution. 

If you want different values, then look to see if it's possible to
change the default resolution used by your software. For example, if you
have Paint Shop Pro 8, the value it uses is in File: Preferences:
General Program Preferences: Units: Default Resolution (the menu varies
slightly depending on the PSP version).

Many graphics programs have the facility to change the resolution
without changing the image data. In PSP 8 this is achieved by using
Image Resize, setting the resolution value and then setting the pixel
dimensions to be the same as the original. In Irfanview it is achieved
by using Image Resize, setting the units to "pixels" and changing only
the DPI value.

The ppi value is only really meaningful if you then go on to print the
image without scaling it. Scaling it for printing causes the value saved
in the file to be ignored.

-- 
Mike Williams
Gentleman of Leisure


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From: Larry Hudson
Subject: Re: resolution question
Date: 24 Dec 2004 21:45:12
Message: <41ccd438$1@news.povray.org>
> The ppi value is only really meaningful if you then go on to print the
> image without scaling it. Scaling it for printing causes the value saved
> in the file to be ignored.

And it's ALWAYS ignored when displayed on-screen, since the screen has a 
fixed resolution.  There, the dimensions in pixels is the only thing 
that's significant.

      -=- Larry -=-


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From: t millican
Subject: Re: resolution question
Date: 25 Dec 2004 19:25:24
Message: <41ce04f4$1@news.povray.org>
one small note:
The BMP format makes for a better image than the JPG format. JPG is 
compressed, so it has an advantage in that it takes less disk space and 
is more suited for webpages, etc. For printing, I'd stick with a 
non-lossy format like bmp and redefine the resolution (render it 
according to the formula given by Neil though) to print.
Some programs will allow you to adjust the compression/lossy values when 
converting the bmp to jpg. Typically, the smaller the disk size, the 
lower quality the image.
Merry Christmas.

Stephen wrote:

> I just ** hope** this isn't covered in the doc'n somewhere, but since I
> can't find the answer to my question, I'll ask:
> 
> What is the native resolution of POVRay - not the rendering size, but the
> number of dots per inch?  One chunk of SW that I have says 96dpi and another
> implies 76ish about some rendered images.
> 
> My standard output type is BMP (oh, well) but I typically like JPGs and can
> work with other file types. My interest is in getting the best possible
> detailed rendering and then if my printer or scaling wants to muddle with
> that, then so be it.
> 
> Any way to get higher resolutions?
>


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From: destroyedlolo
Subject: Re: resolution question
Date: 26 Dec 2004 06:02:04
Message: <41CE9A0E.1000405@yahoo.com>
t millican wrote:
> one small note:
> The BMP format makes for a better image than the JPG format. JPG is 
> compressed, so it has an advantage in that it takes less disk space and 
> is more suited for webpages, etc. 

W/ a qualite ratio > 80%, you can't notice compression artefact on most 
pictures.

> For printing, I'd stick with a 
> non-lossy format like bmp and redefine the resolution (render it 
> according to the formula given by Neil though) to print.

Another alternative is PNG format which is compressed w/ a 
non-destructive algorithm.

> Merry Christmas.

Merry Christmas to all.

Lolo


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From: Stephen
Subject: Re: resolution question
Date: 27 Dec 2004 13:10:08
Message: <41d05000@news.povray.org>
Thanks for the updates.

I'm also looking for more "resolution" in my woodgrain renderings, but I'm
beginning to think that's another issue altogether.

Without destroying this thread completely, are there some brief suggestions
to render woodgrains "clearly" or "in detail", or maybe I'm expecting too
much to see the texture in a full-size view of an object the size of a desk.

Attached is a tiny version of my latest - for reference only - previously
some other images had been posted to P.B.I


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Attachments:
Download 'Chest36x24x18-F.png' (10 KB)

Preview of image 'Chest36x24x18-F.png'
Chest36x24x18-F.png


 

From: t millican
Subject: Re: resolution question
Date: 27 Dec 2004 13:22:28
Message: <41d052e4$1@news.povray.org>
Great. Thanks for the PNG information. I didn't know the details about 
that one.  :-)

I don't know what to say about the wood grains though, Stephen, except 
maybe "scale" or layering textures. I'm sure somebody with more 
experience will post something better soon.

destroyedlolo wrote:
> t millican wrote:
> 
>> one small note:
>> The BMP format makes for a better image than the JPG format. JPG is 
>> compressed, so it has an advantage in that it takes less disk space 
>> and is more suited for webpages, etc. 
> 
> 
> W/ a qualite ratio > 80%, you can't notice compression artefact on most 
> pictures.
> 
>> For printing, I'd stick with a non-lossy format like bmp and redefine 
>> the resolution (render it according to the formula given by Neil 
>> though) to print.
> 
> 
> Another alternative is PNG format which is compressed w/ a 
> non-destructive algorithm.
> 
>> Merry Christmas.
> 
> 
> Merry Christmas to all.
> 
> Lolo
>


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