[Gimp-user] problems with understand how to resize images properly

[albatross <forums gimpusers com>]

Hi, I too have an issue understanding how resizing works, especially with
reference to Word.
I wasn't sure if I should post a new thread, but decided this was sort of
pertinent to my issue.
Please let me know if I should create a new post.

Basically, If I have a big image (a signature, black and white, about 1000
pixels wide), then insert into Word, and resize it ( to about a tenth of it's
size) it looks fantastic.
If I take the image, resize it in Gimp (or anything else for that matter) from
1000 to 100, it looks really bitty and blocky, and inserting to Word it remains
bitty and blocky..

Why is this? Is this to do with the dpi as well? And is there a work around?

Thanks



> Hi menglor,
>
> The process you describe will give you images of different sizes if
> the
> originals have different DPI values, because when you scale an image
> to
> be a certain number of inches in size, the GIMP looks at the DPI
> resolution of the image first, then scales the image to be X number of
> pixels wide/tall based on that DPI and the physical dimensions you
> specify.
>
> Example:  A 300 DPI image scaled to 1" x 1" will come out 300 pixels
> wide.  A 150 DPI image scaled to 1" x 1" will come out 150 pixels wide
> -
> half "size" of the 300 DPI one.
>
> Scaling images by adjusting their size in inches (or centimeters,
> etc.)
> is rarely done.  Useful results require resetting the DPI of images as
> necessary, so a set of images of the same size in inches, cm or etc.
> will also be the same size in pixels.
>
> Or can multiply the size in inches of the output images you want by
> the
> DPI you want, to get the correct dimensions in pixels for /all/ the
> images intended to be the same size when printed.  From that point on,
> you can just scale your whole batch of images to the same size in
> pixels
> and ignore the size "in inches."
>
> The DPI setting in an image is only a number recorded in the file
> header; changing the DPI of an image changes nothing but that one
> number, and as far as I know it does not affect the actual or
> displayed
> / printed size of the image, except when scaling the image in an
> editor
> like the GIMP.
>
> Typical DPI values:
>
> 300 DPI for high quality print
> 150 DPI for office documents etc. where "good enough is good enough"
> 96 DPI for on-screen display
> 72 DPI - a legacy default setting based on printers' "point" size
>
> Note that doubling the DPI of an image while maintaining the same
> print
> size when scaling, multiplies the size of the resulting file on disk
> by
> about 4x.  Exporting images in lossless PNG format (vs. lossy JPG) for
> maximum print quality also creates much larger file sizes on disk.  So
> big, high quality print jobs can take up a lot of space in storage or
> time in transit across the network.
>
> You also mentioned printing via a Word document, and that the sizes
> you
> get are a little off.  I think that's to be expected, because word
> processors were not intended for "pre-press" work, a.k.a. printing
> images with high accuracy.
>
> I use Scribus, a Free desktop publishing application, for pre-press
> work.  Make your images, put them on the page exactly where you want
> them, export the file as PDF and print that:  Viola, accurate results.
>
> For really precise positioning on page, i.e. when printing on peel and
> stick label stock or etc., it may be necessary to print a test page,
> measure any placement errors, and adjust the Scribus master document
> to
> get your required results from that particular printer.
>
> https://www.scribus.net/
>
> :o)

-- 
albatross (via www.gimpusers.com/forums)