I fail at searching

2-ton · **Posted:** Tue May 31, 2011 9:39 am **(#1)**

GIMP Version: 2.6.11
Operating System: Mac OS
OS Version: snow leopard
GIMP Experience: Basic Level

I am not finding what I need via search, and I'm pretty sure this has been discussed...what is the best way to take a large graphic and make it small while still retaining the clarity and sharpness of the large one. I am trying to take a photo, maybe cartoon it or whatever, then make it tiny in order to fit it into an icon. I thought about changing resolution, but then I don't know how to make something in 300 dpi the same size as an 100 x 100 icon at gimp default resolution. So if anyone can point me to the proper boards and threads where this has been commented on, I would totally appreciate it.

paynekj · **Posted:** Tue May 31, 2011 9:48 am **(#2)**

This is probably not what you want, but your request put me in mind of the Meet the Gimp episode about using Inkscape to make a fully scalable graphic:

http://meetthegimp.org/episode-041-is-it-a-hammer/

Oregonian · **Posted:** Tue May 31, 2011 9:51 am **(#3)**

Don't know if this will help.

http://www.gimpchat.com/viewtopic.php?p=14591#p14591

lylejk · **Joined:** Sep 24, 2010 **Posts:** 12518

I'm not sure the best way 2-ton but I usually just use Lanczos3 (GIMP default) followed by some sharpening. Recently though, I came across a cool Gluas preset called Decimation, but it doe require you to crop. Still, it seems to give you better results (at least subjectively). Just noticed that version 0.1.20 doesn't run this preset anymore so I'm going back to 0.1.19 for now because I like this preset. Still have to follow it up with sharpening though. I like using Wavelet sharpening by the way.

Rod · **Joined:** May 16, 2010 **Posts:** 14709 **Location:** USA

That Decimation filter does a fine job on re sizing images smaller.

lylejk · **Joined:** Sep 24, 2010 **Posts:** 12518

Yeah; hoping this technique can actually be ported by a guru into G'MIC; it's one of the best that I've seen going the other way imo. Problem with Gluas is that it keeps the original and pastes the smaller in the corner like one of those oldy droste images that I've seen. lol

Rod · **Joined:** May 16, 2010 **Posts:** 14709 **Location:** USA

I could do it for you in Xara if you would like.

Yeah that was the only thing you have to make a duplicate before you run it...very weird that it saves inside the same image.

2-ton · **Posted:** Tue May 31, 2011 2:46 pm **(#8)**

this might be more than I can handle! I don't have inkscape and wouldn't know how to use it. All I want to do is shrink the image, not animations. Rod, I might take you up on the offer if I find the images I want, thanks! But I still would like to know if it's doable in Gimp.

mahvin · **Joined:** Oct 06, 2010 **Posts:** 4046

http://gimp-tutorials.net/How-to-make-a ... -a-picture

Gms9810 · **Posted:** Tue May 31, 2011 3:03 pm **(#10)**

Rod wrote:

I could do it for you in Xara if you would like.

Yeah that was the only thing you have to make a duplicate before you run it...very weird that it saves inside the same image.

Xara has the best and fastest algorithm to resize images but resizing them too much is almost a lost cause without a lot of degradation.

paynekj · **Posted:** Tue May 31, 2011 3:59 pm **(#11)**

Shall we have a group test to see what different methods come up with?

For my own amusement I've used the full size of this as a test image (it's 2580x2544 pixels):

(click through the image to get to the full size version)

Using my own script to scale it down in 3 steps - widths of 1753, 926 then to 100 (using cubic interpolation) I got to this (with no sharpening)

I'd be interested to see other results

Kevin

ofnuts · **Joined:** Oct 25, 2010 **Posts:** 4739

paynekj wrote:

Shall we have a group test to see what different methods come up with?

For my own amusement I've used the full size of this as a test image (it's 2580x2544 pixels):

(click through the image to get to the full size version)

Using my own script to scale it down in 3 steps - widths of 1753, 926 then to 100 (using cubic interpolation) I got to this (with no sharpening)

I'd be interested to see other results

Kevin

Blur 25x25 plus scale down Sinc/Lanczos:

Attachment:

Kodak1a.png [ 15.57 KiB | Viewed 988 times ]

Idem + unsharp mask (1.0, 1.0, 49):

Attachment:

Kodak1a-unsharpmask.png [ 15.96 KiB | Viewed 988 times ]

Rod · **Joined:** May 16, 2010 **Posts:** 14709 **Location:** USA

Gms9810 wrote:

Rod wrote:

I could do it for you in Xara if you would like.

Yeah that was the only thing you have to make a duplicate before you run it...very weird that it saves inside the same image.

Xara has the best and fastest algorithm to resize images but resizing them too much is almost a lost cause without a lot of degradation.

Here it is in Xara Designer 6

2-ton · **Posted:** Tue May 31, 2011 9:21 pm **(#14)**

I tried, and found that using the resize tool works pretty good, especially if you do it in steps, then use the unsharp mask to sharpen the image. Not perfect, but not bad, but maybe I am trying to do the impossible? This is the tutorial that got me wanting to try and make a very sharp and crisp icon. gimptalk thread

Rod · **Joined:** May 16, 2010 **Posts:** 14709 **Location:** USA

Interestingly enough after downloading all the examples all 3 are almost exactly the same.

Up close and personal. :lol

2-ton · **Posted:** Tue May 31, 2011 9:40 pm **(#16)**

wonder if higher resolution would help, but won't be able to try for a while, plus I'm not sure how to figure out how many pixels to keep the 100 x 100 standard icon size.

lylejk · **Joined:** Sep 24, 2010 **Posts:** 12518

Decimation (Gluas; cropping from such a huge image was a laugh; lol) followed by wavelet sharpening.

2-ton · **Posted:** Tue May 31, 2011 9:49 pm **(#18)**

that looks the best, now I suppose I must get this gluas program. Argh, I am so bad at installing new softwear!

lylejk · **Joined:** Sep 24, 2010 **Posts:** 12518

I know it's subjective, but I feel so too 2-ton. You need to get version 0.1.19 though (0.1.20 won't run Decimation for whatever reason). The Japanese site I linked (believe I did anyway) earlier host's 0.1.19. Still don't like having to crop though. I'm still convinced a G'MIC programmer can do Decimation right.