How do I best scale a screenshot in Gimp to avoid a blurry effect?

I'm using Gimp 2.6.1 on Windows Vista.

I take a screenshot using the Print Screen button and paste it into Gimp.

I crop away some of the edges, then I select Image > Scale Image... and reduce this to around 400px, maintaining the ratio.

I have tried each of the interpolation options, None, Linear, Cubic and Sinc (Lanczos3) and all still result in a blurry image.

Any tips on how to get a better result?

Original:

Original

Linear:

Linear 400px

Cubic:

Cubic 400px

Sinc:

Sinc 400px

No interpolation:

No interpolation 400px

It's not so much that I want to be able to read the text, I'd just like it to be less blurry.

Thanks.

Adrian Lynch

Posted 2010-09-09T12:37:36.980

Reputation: 161

It might help if you posted an example image and explained the specific problems. – Velociraptors – 2010-09-09T13:02:20.927

Remember to never use jpeg for screenshots. Use .png, or at least .gif. Sorry for having to remind you, but many people do not realise this. – paradroid – 2010-09-09T13:24:50.530

@Velociraptors - Added some files. – Adrian Lynch – 2010-09-09T13:31:00.510

@jason404 - Good point, I'll have a look at other image formats. – Adrian Lynch – 2010-09-09T13:31:29.213

jpeg is good for compressing images with graduated colour, like photographs. Compressing computer graphics and text with jpeg will lead to blurriness and artefacts, especially as you increase the compression level. .gif does a much better job, and with .png you can compress 'losslessly', with the image looking exactly the same as the uncompressed original. – paradroid – 2010-09-09T14:09:35.653

Answers

Do you mean "blurry" or "reduced detail"? Obviously, you lose information when resizing down. I've always used None and my screencaps ended up being used in publications, ads, etc.

The way to get a good screencap at small size is to avoid needing to reduce very much, for instance by shrinking windows to the very smallest size that still shows all the details you need, then capturing just that window (alt-PrtSc).

CarlF

Posted 2010-09-09T12:37:36.980

Reputation: 8 576

1next to shrinking windows, also reduce the screen/desktop resolution. Windows can render things like texts (fonts) in lower resolutions better then scaling a screenshot – jor – 2010-09-09T13:13:01.617

I would use Sinc interpolation as it gives the least blur, other than the blocky none.

When complete, do a sharpen pass to tighten it up. Works well for me.

Gringo Suave

Posted 2010-09-09T12:37:36.980

Reputation: 932

You will always lose details when scaling-down an image. The more the difference in sizes, the more details you lose.

The solution would be to either crop your image first to the bare minimum, or take a minimal screenshot in the first place by using a better mechanism.

My favorite screenshot product is the free Gadwin PrintScreen. It has many options, can interface with other software products and is easy to use. It also has an Area mode where you can drag a rectangle around the area you want to take, and then you can further drag the rectangle's sides for finer adjustments. It can store the image for you and open it inside Gimp.

harrymc

Posted 2010-09-09T12:37:36.980

Reputation: 306 093

pixels are used to represent the image.
when you scale down you loose pixel information resulting in blurry images
The more you reduce your image’s dimensions by scaling down, the fewer pixels there are available to render the details of the image
This site has a similar question , look for the answer
This site offers some tips to reduce blurriness

subanki

Posted 2010-09-09T12:37:36.980

Reputation: 6 702

-1

Convert the image to 300 dpi before you resize.

scott

Posted 2010-09-09T12:37:36.980

Reputation: 1

4Please elaborate on this answer. How is it performed in GIMP? (Which is what is asked for.) – Johan Karlsson – 2012-11-08T08:21:48.633