resizing image creates blurry image

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resizing image creates blurry image

Misslo777
I'm trying to resize an image from 398x398 to 28x28.  I've followed several
guides and each time gives me the same effect.

Things I've tried:  

1. Resize to 28x28 using NoHalo
2. Apply Gaussian blur then resize using NoHalo, finally using Unsharp Mask to
sharpen
3. Resize to 28x28 using LoHalo
4. Apply Gaussian blur then resize using LoHalo, finally using Unsharp Mask to
sharpen

each of them came out with the same effect of the image being blurry.  I'm not
sure what I'm doing wrong and none of the guides I've seen seem to help.

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resizing image creates blurry image

Misslo777
I   Hope someone helps with this - I also have an image that looks like too few
pixels and is blurry - ish - ---

As someone learning - and decent at the basics - I find it difficult to get
specific help - and dealing with Book Covers for Ingramspark and KDP - they are
Exacting in what they will accept - and I find it hard to do the little things
at the end of all the hard artistic work to get the covers accepted ... I'll be
watching this thread ....

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Re: resizing image creates blurry image

Owen Cook
In reply to this post by Misslo777
Are you talking pixels as the unit, ie, 398x398 pixels and trying to reduce that to 28x28 pixels.

If so, I think you are going to be out of luck as the reduction is too great.

Using reductio ad absurdum, what would you expect if you tried to reduce the image to 1x1 pixel?

You cannot expect to have anything like the same information (image likeness) when reduced to such a small amount, approx .6% of the original).



Owen

>
> I'm trying to resize an image from 398x398 to 28x28.  I've followed several
> guides and each time gives me the same effect.
>
> Things I've tried:  
>
> 1. Resize to 28x28 using NoHalo
> 2. Apply Gaussian blur then resize using NoHalo, finally using Unsharp Mask to
> sharpen
> 3. Resize to 28x28 using LoHalo
> 4. Apply Gaussian blur then resize using LoHalo, finally using Unsharp Mask to
> sharpen
>
> each of them came out with the same effect of the image being blurry.  I'm not
> sure what I'm doing wrong and none of the guides I've seen seem to help.
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resizing image creates blurry image

Misslo777
WOW - you are assuming the worst of me - I guess newbies overall do that do
people ...

but not - I want increased definition MORE pixels -   I can get  the error
notice from ingramspark if seeing that will help you ... ???

Anyway - thanks for answering - we need a more vibrant help community here for
GIMP since the other options are literally robbing all new start up users.

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Re: resizing image creates blurry image

Liam R E Quin
In reply to this post by Misslo777
On Fri, 2018-11-09 at 19:21 +0100, firefly24 wrote:
> I'm trying to resize an image from 398x398 to 28x28.

Since 398 isn't an exact multiple of 28, it may help to crop it first
to 392 pixels by 392. Then scale down to 1/7th the size (56 x 56) and
use curves to make sure you still have contrast, then scale down 2x to
14x14 and sharpen.

Make sure the image is in 16bpp or 32bpp precision (assuming Gimp 2.10)
and RGB, not indexed.

Without seeing the original image it's hard to give better advice. The
images on the front of fromoldbooks.org are mostly scaled down with
Gimp in lohalo mode, often to between 1% and 3% of the original height,
but at 200x300 pixels i have a chance of sme detail.

slave ankh




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resizing image creates blurry image

Misslo777
>Since 398 isn't an exact multiple of 28, it may help to crop it first
>to 392 pixels by 392. Then scale down to 1/7th the size (56 x 56) and
>use curves to make sure you still have contrast, then scale down 2x to
>14x14 and sharpen.
>
>Make sure the image is in 16bpp or 32bpp precision (assuming Gimp
>2.10)
>and RGB, not indexed.
>
>Without seeing the original image it's hard to give better advice. The
>images on the front of fromoldbooks.org are mostly scaled down with
>Gimp in lohalo mode, often to between 1% and 3% of the original
>height,
>but at 200x300 pixels i have a chance of sme detail.
>
>slave ankh

Thank you for the advice.  I'll try that.  Attached is the original image.  I've
also converted to svg as well to try and better handle the scaling.

Attachments:
* http://www.gimpusers.com/system/attachments/1047/original/RageHi.png

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resizing image creates blurry image

Misslo777
In reply to this post by Misslo777
>I'm trying to resize an image from 398x398 to 28x28.  I've followed
>several guides and each time gives me the same effect.
>
>Things I've tried:  
>
>1. Resize to 28x28 using NoHalo
>2. Apply Gaussian blur then resize using NoHalo, finally using Unsharp
>Mask to sharpen
>3. Resize to 28x28 using LoHalo
>4. Apply Gaussian blur then resize using LoHalo, finally using Unsharp
>Mask to sharpen
>
>each of them came out with the same effect of the image being blurry.
>I'm not sure what I'm doing wrong and none of the guides I've seen
>seem to help.

With such a large percentage reduction you are always going to lose a lot of
detail. There is absolutely no way around this. You just can't represent the
same amount of information in such a small number of pixels.

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