Shrinking images

klambert

Ca Plane Pour Moi
How do you shrink images with out them going pixalated? I would like to shrink an image down to 240 by 180. I want to avoid using adobe photoshop because that is mega expensive.
 
Just use IrfanView. It's painless and easy. I'll put a tutorial up for you tonight. Just watch this space for the URL,

Regards,

John
 
G'day Klambert,

I've done the tutorial. It shows how to reduce a JPG file, but if you have a gif file I think you will figure it out. There's also a video I dug up from my archives covering the same subject. Just use the tutorial's settings though, not the ones on the video.

I'll do a similar tutorial for gif's because they can also be transparent. That will be in a few days.

Download IrfanView even if you decide to go with any of the other stuff mentioned here. Over 44 million people have used IrfanView and that should say it all. Don't bother with the plugins at this stage. many are only demos or trials. Just download the main program. believe it or not, it's just over a megabyte in size.

Good luck. Here's a link to the tutorial because it's not associated with my web site yet.
 
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How do you shrink images with out them going pixalated? I would like to shrink an image down to 240 by 180. I want to avoid using adobe photoshop because that is mega expensive.

It depends upon the image you are trying to resize, and the size of the original relative to the reduced image. If you're trying to go from a full screen shot with very fine detail to 240 x 180, it may not be possible to avoid pixellation, otherwise as a general rule, pixellation is usually more of a problem when increasing size (from 240 x 180 to 720 x 480) than when decreasing size..

ns
 
..and when you shrink an image make sure to choose a 'resample' mode. This tells the program how to combine adjacent pixels in the original image to make a smaller number of pixels in the reduced image.

The coarsest resampling method, I think, is called 'nearest neighbour' - it can give rough looking results, but sometimes it's appropriate because it tends to preserve hard edges. Other methods, such as 'bicubic', give smoother results because they average nearby pixels to generate the result.

Sometimes after shrinking an image it may be of benefit to 'sharpen' it. This reduces the fuzziness you sometimes get from re-sampling.
 
Dinorius_Redundicus, thanks for all that, but it looks like you haven't read the tutorial I did for Klambert. Everything is covered there.
 
No not everything is covered. You're correct, I didn't read your tutorial because I already know how to use IrfanView. But having read it now, I notice it doesn't actually say anything about the different types of re-sampling and how they affect the quality of the end result. The original question was how to avoid pixelation, so I still think it's quite germane to expand on that aspect.
 
Snippet: The original question was how to avoid pixelation, so I still think it's quite germane to expand on that aspect.

Did you? Everything you said except "nearest neighbour" is covered in the tutorial plus some. "Nearest neighbour" may be a phrase specific to another program you use. I don't think IrfanView (which you also suggested) has that option, but Klambert is welcome to experiment with the available filters if he so chooses.

Personally, I thought that "pixelated" didn't describe the problem clearly. Pixelation only happens when enlarging. Images going out of focus during the reduction process is usually due to the crappy resolution of PC monitors. This can often be fixed by using the Sharpen option as you suggested. My tutorial also covered that along with "before and after" images.

If I'm not on the right track, it's probably because you and I are interpreting the word Pixelation differently. Maybe you could help Klambert and I by telling us how it should be done and where we may find our nearest neighbour.
 
Personally, I thought that "pixelated" didn't describe the problem clearly. Pixelation only happens when enlarging. Images going out of focus during the reduction process is usually due to the crappy resolution of PC monitors.

Sorry. I know from personal experience that there is are other circumstances which can cause what at least appears to be pixelation (though, I suppose that one can argue that this set, too, is case of enlarging). If one has a level of detail that is acceptable at a larger resolution, taking as an example the lettering in a the reporting marks on a boxcar, and lowers the resolution, the lettering can become pixelated in the smaller image. I have seen the same phenomenon on other types of fine architectural detail, where things like main stairs at the front of the building, some detail at the roof line, and even shingle and brick patterns can show what at least appears to be pixelation, even though the image is being reduced.

ns
 
Hi mjolnir. You're absolutely right. More so with GIF files and particularly lettering. The reason is to do with the resolution of a PC monitor and little else. At 96 pixels to the inch in both directions, heavily reduced lettering will just become blocks on mumbo jumbo. There's absolutely nothing you can do about it. I assumed Klambert was talking about photos rather than lettering, so that's why I did a tutorial on photos.
This letter S uses about 1,500 pixels, so the curves look okay.
This letter S uses about 100 pixels, so it's not going to be so crisp. That can still be pretty big lettering on a box car. It gets worse when shades are involved. The computer program has to decide what shade to use when a pixel should contain more than one colour. A pixel can only be one colour so the program must make a choice. It does so by making adjacent pixels one or two shades brighter or darker. If the program gets it wrong, the results can, and usually do look out of focus. I guess that'as what Dinorius_Redundicus means by nearest neighbour, but if that option is available in IrfanView, I've managed to miss it all these years. I always use Corel PhotoPaint for the curley stuff, but that program costs money.

IrfanVeiw is free but it tries hard to get it right. Photoshop and PhotoPaint cost a lot of money but they try even harder.

I spent 14 years as the manager of a printing plant at what is now Deakin University in Burwood Victoria. I spent most of that time in Pre-Press. I reckon I'm pretty well versed on this subject, but most people find it to boring or overwhelming. Writing a book about it isn't going to make anyone rich.
 
G'day Klambert,

I've done the tutorial. It shows how to reduce a JPG file, but if you have a gif file I think you will figure it out. There's also a video I dug up from my archives covering the same subject. Just use the tutorial's settings though, not the ones on the video.

I'll do a similar tutorial for gif's because they can also be transparent. That will be in a few days.

Download IrfanView even if you decide to go with any of the other stuff mentioned here. Over 44 million people have used IrfanView and that should say it all. Don't bother with the plugins at this stage. many are only demos or trials. Just download the main program. believe it or not, it's just over a megabyte in size.

Good luck. Here's a link to the tutorial because it's not associated with my web site yet.

Thanks very much johnk for you efforts. This contributes to putting content on my site.
 
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