I know its the printing step that is the culprit, but I don't know how to fix
it.  I printed some images from xv and they look like crap compared to what I
see on the screen.  AFAIK screen resolution is always 72 dpi regardless of
how big the monitor is.

Mike


Thomas Charron wrote:

> In article <3A105C74.B558AA0F@scripps.edu>, "Michael DiDonato"
> <did### [at] scrippsedu> wrote:
> > Is there a way to specify the resolution of the images created by
> > POV-RAY?  I have created a couple of molecular graphics which look great
> > on screen but when they are printed, they contain jaggies even though
> > they were antialiazed.
>
>   I think the printer is more at fault then the image at that point..
>
> > Furthermore, when I open the TGA file in xv (or any other graphics
> > program) it says the resolution is 72dpi.  I would like this to be at
> > least 600dpi.  Is there a way to specify this in POV-Ray?
>
>   DPI is really a *bad* term.  You see, where is there a reference to an
> 'inch' in a digital image?  I'd imaging that xv is figuring out the size
> of the image, compared to the size of your screen.  I mean think about
> it..  Do my images magically have a higher DPI when displayed on a higher
> resolution monitor?
>
> > Any help is appreciated.
>
>   What application are you using the print these images?  What printing
> system are you going thru?  And best of all, what printer are you using?
> Remember, just becouse a printer can print at 600 DPI doesn't mean the
> application is giving it information at this level..
>
>   DPI is simply the number of pixels in one inch.

--
*******************************
Michael DiDonato, PhD
The Scripps Research Institute
Department of Molecular Biology
Maildrop MB4
10550 North Torrey Pines Road
La Jolla, CA, 92037

Tel: (858) 784-9261
FAX: (858) 784-2277
*******************************

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My world is currently PC-based (Windows 98/NT) so this may not apply to
you...

If you generate an image that is 1000x1000 pixels and print it as a 2"x2"
square you will have 500dpi.

If you print the same image as a 4"x4" square you will have 250dpi... and it
will look worse.

Most screens average about 72dpi, but in Windows you can adjust your screen
resolution.  For example if you set your resolution to 1280x1024 and view
the image you will see a certain dpi, and if you subsequently change your
resolution to 800x600 you will see approximately 2/3 the dpi... and it will
look worse.

In general I think you want to print at 300 dpi or better to have a good
image.  Generate a big picture and print it in a small square to achieve
adequate resolution.

I use Paint Shop Pro for general graphics operations like this.  Sorry I
don't know of a comparable unix or mac program, but I'm sure they exist.

"Michael DiDonato" <did### [at] scrippsedu> wrote in message
news:3A107956.CA89EB0E@scripps.edu...
I know its the printing step that is the culprit, but I don't know how to
fix it.  I printed some images from xv and they look like crap compared to
what I see on the screen.  AFAIK screen resolution is always 72 dpi
regardless of how big the monitor is.
Mike

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I don't printout anything that is less than 3200x2400 res if I'm looking 
for quality prints. Printing in Linux is not the way to go as most 
printer drivers with advanced options are not written for Linux. I could 
not get my printer to print very well in Linux but in W98 it's just 
great (Epson Photo 1200). That is just what I have seen but your printer 
may differ. 
  Michael DiDonato wrote in message <3A105C74.B558AA0F@scripps.edu>...
  Is there a way to specify the resolution of the images created by 
POV-RAY?  I have created a couple of molecular graphics which look great 
on screen but when they are printed, they contain jaggies even though 
they were antialiazed. 
  Furthermore, when I open the TGA file in xv (or any other graphics 
program) it says the resolution is 72dpi.  I would like this to be at 
least 600dpi.  Is there a way to specify this in POV-Ray? 

  Any help is appreciated. 

  Mike 
    

-- 
*******************************
Michael DiDonato, PhD
The Scripps Research Institute
Department of Molecular Biology 
Maildrop MB4
10550 North Torrey Pines Road
La Jolla, CA, 92037

Tel: (858) 784-9261
FAX: (858) 784-2277
*******************************

Post a reply to this message

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Michael DiDonato wrote:
> 
> Is there a way to specify the resolution of the images created by
> POV-RAY?  I have created a couple of molecular graphics which look
> great on screen but when they are printed, they contain jaggies even
> though they were antialiazed.

> Furthermore, when I open the TGA file in xv (or any other graphics
> program) it says the resolution is 72dpi.  I would like this to be at
> least 600dpi.  Is there a way to specify this in POV-Ray?

	You simply control the size of the POV image so you have 600 pixels to
print at that resolution. For example, create 800x600 for a 1.333x1 inch
image. 

	That last time I tried something like that was on a much slower machine
and it ate up most of the processing doing the size conversion for an HP
560C. 

-- 
Want to know how Palestinians feel? Imagine if Israel
had been declared in your country. 
	-- The Iron Webmaster, 275

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Thomas Charron wrote:

>   I think the printer is more at fault then the image at that point..

It's a sort of moire between the printer's diffusion and the image's
resolution, I think. I get it when I try to print normal size
(640x480~1600x1200) images blown up to one page.

--
David Fontaine  <dav### [at] faricynet>  ICQ 55354965
My raytracing gallery:  http://davidf.faricy.net/

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I don't understand this.
  AFAIK the dpi value in an image format (if the format supports it) is
just a value. It doesn't affect anything. The image will still have the same
amount of pixels and wouldn't care less about some value in its header
called "dpi".
  If you want to change that dpi value, then just open the file with a
paint program and change that dpi value. What's the problem? If that value
has some effect when printing then it may be relevant, but it's completely
irrelevant with respect to the image file itself.
  If you want more accuracy, render your image with more pixels.

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/

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I have been printing some images recently and can give you some direction.
First, the printer resolution is going to be much higher than your monitor.
For example my 19 inch monitor is actually about 14 inches side-to-side and
is currently at a resolution of 1024 across.  This works out to about 73
pixels per inch.  My printer on the other hand prints at 720 dots per inch.
If I print an image that is fine "screen wise" it will be quite pixelly
printed full page on the printer.  In order to get printable images you have
to increase the render size.  I have gotten some images printed that are 34
inches wide by 25 inches tall without ANY pixels being apparent.  (Not on my
printer though, I go to a printing service.) The image size to make that
happen though is 10240 by 7680 (not a typo) so it is an order of 100 times
larger to make a clean printout.  You might get away with half that size
depending on the final size of the printout.

Of course that also means it takes *FOREVER* to render...


"Michael DiDonato" <did### [at] scrippsedu> wrote in message
news:3A105C74.B558AA0F@scripps.edu...
Is there a way to specify the resolution of the images created by POV-RAY?
I have created a couple of molecular graphics which look great on screen but
when they are printed, they contain jaggies even though they were
antialiazed.
Furthermore, when I open the TGA file in xv (or any other graphics program)
it says the resolution is 72dpi.  I would like this to be at least 600dpi.
Is there a way to specify this in POV-Ray?
Any help is appreciated.
Mike

--
*******************************
Michael DiDonato, PhD
The Scripps Research Institute
Department of Molecular Biology
Maildrop MB4
10550 North Torrey Pines Road
La Jolla, CA, 92037

Tel: (858) 784-9261
FAX: (858) 784-2277
*******************************

Post a reply to this message

Often, HTML code is disliked in newsgroups.
______
David McCabe
dav### [at] maccom
http://homepage.mac.com/davidmccabe/index.htm
God is good!

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In article <B63828CB.2CC9%dav### [at] maccom>, David 
<dav### [at] maccom> wrote:

> Often, HTML code is disliked in newsgroups.

Especially on these groups, where many people don't use newsreaders 
which support HTML and where the posts are kept as long as possible(HTML 
posts take more space).
However, Warp's message didn't use HTML, neither did any of the other 
messages in this thread...so what made you post this?

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><

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On Wed, 15 Nov 2000 15:37:24 -0500, Chris Huff wrote:
>However, Warp's message didn't use HTML, neither did any of the other 
>messages in this thread...so what made you post this?

Probably Warp's signature. :)

-- 
Ron Parker   http://www2.fwi.com/~parkerr/traces.html
My opinions.  Mine.  Not anyone else's.

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