[ale] LightScribe for Linux

[Michael B. Trausch]

On Tue, 2011-06-28 at 15:32 -0400, aaron wrote:
> On 2011/06/28, at 13:07 , Michael Trausch wrote:
> > You can set the DPI in the GIMP, too. At image creation time is the  
> > best bet.
> >
> > Any time I create images in the GIMP, I create them at 600 dpi. I  
> > will crop
> >
> > and/or scale down as necessary for the final product.
> >
> Unfortunately, the DPI setting is only a reference number when working
> with bitmap images.  It doesn't in any way force the pixel counts of an
> image to conform to that resolution.  In electronic bit map graphics,  
> pixel
> count is the ONLY relevant measure of actual resolution. if you want
> your final output to print at best possible resolution for 600 dpi on an
> 8.5x11 sheet of paper, the pixel count of your source image needs to
> be 5100 by 6600 pixels.

Well, not strictly speaking.  In certain formats, yes.  In others,
absolutely not.  For example, you can save a 5100x6600 PNG graphic, and
mark it as 72 dpi, and it's going to be HUGE when you try to use it in a
context where inches or centimeters are required.  ;-)

> And then you output it as a TIF file or some other lossless format
> so don't lose resolution to compression artifacts.

Indeed.  My preference for the final format of most imagery is PNG,
simply because of its lossless compression and ability to support alpha
channels.

> > I always save as xcf
> > (native GIMP format) for the original, and only ever save things as
> > png/gif/jpeg/whatever when I am exporting a final graphic.
> 
> PNG's deflate is a lossless compression.  PNG images
> are widely supported in web clients where TIF is more of a
> working and widely supported interchange format for image
> editing programs.  PNG supports both full depth per pixel
> to 48 bits or can use a 256 indexed palette mode (like GIF).

For that matter, you can have an indexed palette of any size in a PNG
file, which makes it rather convenient for when you have to transfer
files over a very slow link and the quality of the image isn't the item
of paramount import.

> GIF is extremely limited in color range as it _only_ supports
> 8 bit indexed colors  (a palette of 256 colors from 16 million)

Yes, I always hated GIF for that.  I always wondered, too, why people
were so angry over the patent issues with GIF and the compression that
it employed.  I thought that there was no great loss with the inability
to use GIF for a long time.  Web browsers didn't take that long to pick
up support for the PNG format, and it was (is!) far, far superior...

> JPEG is a lossy compression format, with some loss seen
> even at its highest quality / lowest compression settings. Like
> PNG, though, it is widely supported in web applications and
> is usually the best choice for photographic images on the net.

Well, at least until we all have exabyte hard disks and links to the
Internet that can be measured in Gb/s... ;-)

	--- Mike