Re: [Gimp-user] Quality loss when reducing the dimensions of my image

[Steve Kinney <admin pilobilus net>]

On 01/04/2018 12:39 PM, qsdqsd wrote:
> Hi everybody,
>
> I was wondering if it was normal to see a loss of quality after reducing an
> image with Image --> scale image or with the (Shift+T) tool.
> I can see more blur. A less define edge.
>
> I thought a quality loss never happened when reducing an image but when
> increasing it size..

When increasing the size of an image (in pixels), the averages adjacent
pixels together as necessary to spread the same pattern across a larger
number of pixels.  This does produce a visible blurring effect where the
original had sharp edges.

When scaling down, the pixels along high contrast edges in an image are
again averaged together, but because the visible size of the affected
areas is decreased the loss of resolution is not as visible. But if you
"zoom in" and look at the image at the same size (in cm on screen) as it
was before scaling down, the loss of resolution will be visible.

:o)