<

How do I enlarge my image without losing quality?

Published on
85,139 Points
70,739 Views
24 Endorsements
Last Modified:
Awarded
by Todd L'Herrou

As you might guess, this is a common problem, and a common type of question. Unfortunately, small images or highly compressed images (including JPG format images in particular) provide very little to work with when trying to enlarge them. It simply isn't possible to display information which isn't there. The compression for JPG images also often introduces artifacts (squiggly lines, noise around edges, blurring, a smeared appearance, etc) which can be quite distracting when enlarged.

Whenever possible, it's best to go back to the original, but if the original is small to start with, or just isn't available, here are some approaches worth trying, and in some cases the results can be quite satisfactory.

For all of the following approaches, when you try to make your images larger, the software tries to guess, based on the information that is there, what the missing information might be. There are a number of methods that can be used to make that "guess" about the missing information. Some of the steps you can take depend on the software you have. Most graphics software offer a range of different options for resizing images, with some options working better on some images or image types than others. What works best in general may not be best for your specific images.

In Photoshop, for example, there are some different settings for the software to use when re-sizing the images. If you look at the "Image Resize" box in Photoshop, you should see that there is a checkmark at the bottom of it, marked "Resample Image". Next to that is a pulldown box for the algorithm to be used to resample the image. You might try experimenting with those algorithms, to see what works best for you - bicubic is usually best for photos, but not necessarily for other images.
For the free software Irfanview, you can choose, under the Resize / Resample menu item, to resize or resample the image. If you select "Resample", there are several alternatives which may be selected. I have shown below a series of images enlarged to 4 times the original size using Irfanview. The first of these is simply resized, creating a pixellated (or "jaggy") look. The other three were resampled using various options: Hermite, B-Spline, and Lanczos methods. As can be seen, the results differ - for example, the Lanczos method, while bringing out detail, also enhances the previously mentioned jpg artifacts -  so ultimately you, the user, must decide which is best for YOUR image.

Another option that can be used is stepped enlargement. Some images seem to benefit from enlarging in steps rather than all at once. Try using about 5 steps of about 20% of the total enlargement you want, and see if that makes a difference. So, rather than going from 120pixels to 500pixels in a single step, you would go from 120 to 200, from 200 to 280, etc.

You can also slightly oversize the image by about 20%, and apply some light blurring, then resize back down to your final size. This usually works best when the size change is not extreme.

There is also specialty software for image resizing. This software is often used for commercial work when the original source file is already high-resolution, but must be enlarged further for large-scale printing. Be prepared to spend some $$$ if you go this route. The best known of these specialty programs is Genuine Fractals.

Finally, I have to point out AGAIN that all of these methods are extremely limited when working with small JPG originals. You are NOT likely to get results that are particularly satisfactory, but they may help. You may have better success with other formats (for example, the TIF and PNG formats are uncompressed, which can mean larger file sizes, but no data was lost when the file was originally saved).

Unfortunately for those trying to enlarge a reduced-size photo, there's no movie-style solution, where you can zoom in on some tiny detail, blow it up to the size of a computer monitor, and read the date on the newspaper to solve the mystery.

 Resized Image Image Resampled using Hermite method Image Resampled using B-Spline method Image Resampled using Lanczos method
24
Comment
Author:lherrou
  • 5
  • 5
  • 3
  • +8
21 Comments
LVL 18

Expert Comment

by:WaterStreet
Very nice and helpful article that takes the mystery out of a subject that should be very popular even with less experienced users.  It seems to tell all the basics and a little more in an easy to understand and brief article.  It got my vote above.
0
LVL 1

Expert Comment

by:apochimongitus
Good article, well written and informative. It presents the problems and solutions in a clear manner. <-- I sound like a primary school teacher :S... but I still think the article was good.
0
LVL 47

Expert Comment

by:aikimark
It is worth looking at context-sensitive resizing.  This technology has been incorporated into several commercial, free, and web-based image editing applications.
www.youtube.com/watch?v=vIFCV2spKtg
0
Cloud Class® Course: CompTIA Cloud+

The CompTIA Cloud+ Basic training course will teach you about cloud concepts and models, data storage, networking, and network infrastructure.

LVL 38

Author Comment

by:lherrou
Nice point, Aikimark. Content-sensitive resizing has been licensed and incorporated into Photoshop CS4, and Liquid Resize was purchased by the company that owns Genuine Fractals, but perhaps you can point us to free or web-based applications?
0
LVL 47

Expert Comment

by:aikimark
I found a link to a python implementation, but the linked-to page was broken/missing.  I didn't find the web site that was an early implementer of context-sensitive resizing.  I don't know what happened to it.

Here are some PC-resident solutions:

http://pcwin.com/Multimedia___Design/Authoring_Tools/Image_Resize_Guide_Lite/screen.htm

Shareware ($19.99)
http://www.softwaregeek.com/download/just_resize_my_photos.html

Shareware ($45)
http://www.freedownloadscenter.com/Multimedia_and_Graphics/Graphics_Editors/Image_Resize_Guide.html

Shareware ($65)
http://www.filedudes.com/QuickResizer-download-12029.html
0
LVL 38

Author Comment

by:lherrou
Hmm. I couldn't find an actual product at your first link, and the last link is just an implementation of M$'s tools already on a PC, I don't see any reference to context-sensitive resizing there. The second link, Just Resize My Photos, does not have any reference to context-sensitive resizing, and their actual website (not the link you provided) is dead. The software in the third link (actual website: http://tintguide.com/en/imageresize.html) appears promising, but only discusses decreasing image size, NOT increasing, which is the focus of my article.
0
LVL 47

Expert Comment

by:aikimark
I did not do a complete analysis, tracking down every link and evaluating the software.  I appologize.  I had hoped the python implementation would be available.

My first post referenced context-sensitive resizing, which was not mentioned in the article text.  It is a fairly new technique (SIGGRAPH2007).  I knew that Adobe was going to put it into Photoshop, but didn't know they had already released a version with that feature.  If you took advantage of this CS4 (new) feature in your article, I missed its reference.

Context-sensitive resizing is only one of the techniques.  You have done a good job explaining other techniques and comparing them.
0

Expert Comment

by:sameerb5
thanxs a lot for sharing this informative article which is well wriiten.It presents the problems and solutions in a clear manner.
0
LVL 47

Expert Comment

by:aikimark
@lherrou

Adobe just announced a context-aware fill feature.  It is also very slick.
http://www.youtube.com/watch?v=NH0aEp1oDOI
0
LVL 38

Author Comment

by:lherrou
Wow, as someone who has had to do some of the slow slog on actions like that, it looks amazing. From another perspective, that's really scary! Kind of reminiscent of the old USSR revisionism in photos.
0
LVL 47

Expert Comment

by:aikimark
Trotsky?  Who is that? ;-)
0
LVL 7

Expert Comment

by:peea
Very interesting and useful article it is.

I notice on Mac OS X, you may zoom the screen by holding Ctrl key and scrolling the mouse wheel. The zooming effect is impressive as it does not lose quality too much compared to other normal zooming.

Does Mac OS X use the same techniques discussed here?
0

Expert Comment

by:dhiraj79
Hi ,
I read a very Interesting article about ovelaying text on Image.
The URL is as below.
http://www.freejobsreference.com/dotnetforums/47-How-to-write-or-superImpose-or-Overlay-Different-Text-on-Images-in-ASP-NET.aspx
0
LVL 1

Expert Comment

by:emblitz
I've had some success enlarging images using the "blow up" filter for photoshop from alien skin software
http://www.alienskin.com/blowup/

now obviously some images are way to small to work with, but playing around with the filter settings can usually get some decent/usable results. If you have an image emergency... ie/ lost your high res sourcefile, this could be a lifesaver.

theres a free 15 day trial on their site. Worth a look if you're stuck in a tight spot and really need to get your image larger/better quality. I've sucessfully saved some images for clients this way...they couldn't thank me enough! Literally called me a "miracle worker"

ps...im not affiliated with the company inany way..I'm a designer & animator. I just find this plugin super useful and i really like it. =)

cheers!
0

Expert Comment

by:sheana11
Thanks, experts, this was a VERY informative article/discussion!
0
LVL 111

Expert Comment

by:Ray Paseur
Todd: I looked for you on E-E today and this (see image) is what I found.  All the best, Ray
How poetic!
0
LVL 38

Author Comment

by:lherrou
Yes, exactly so.

EE prompt
0
LVL 111

Expert Comment

by:Ray Paseur
Tried so hard, for more than two years, to get their eye on the ball about the search "functionality" to no avail.  And they wonder why things are going poorly?  Oh well...
0
LVL 38

Author Comment

by:lherrou
I know. And you weren't the only one trying. And now they are essentially giving up on Q&A.
0
LVL 111

Expert Comment

by:Ray Paseur
Well, I agree that they have lost this to StackOverflow in a multi-year death-spiral.   Will be interesting to see how they might try to replace the old E-E!

Probably time for an alumni group, if one doesn't already exist. :-)
0
LVL 2

Expert Comment

by:Ryan
Another simple answer is to simply print the image and then scan it.
0

Featured Post

Cloud Class® Course: Python 3 Fundamentals

This course will teach participants about installing and configuring Python, syntax, importing, statements, types, strings, booleans, files, lists, tuples, comprehensions, functions, and classes.

Join & Write a Comment

The goal of the tutorial is to teach the user how to make his/her own presets while editing so it is easier to edit there photos. Create a preset you like and copy that setting then save it in to your presets folder.
If you are (or ever were) a Mozilla Firefox user, I suggest that you immediately head over to this Experts Exchange article: What to do when PaperPort crashes, hangs, or fails to start - popular fix for Mozilla Firefox users (https://www.experts-…

Keep in touch with Experts Exchange

Tech news and trends delivered to your inbox every month