enlarging pictures

[TomTom]

I have been told that you can get programmes and with them you can blow up photographs, keeping the quality? I have a few small photos on my comp which I would like blowin' up so can anyone name the programmes? can you download them? anyone got one? any good?

Thanks?

[Cetti]

There are just so many of these programs Tom Tom, that it's just a case of choosing the one you like the look of.

My favourite remains IrfanView, but Picasa2 and FastStone Image Viewer are all brilliant - and free!

[IndieSinger]

Let's not that you cannot genuinely blow up a picture from its original size without losing some image quality. The resolution of a picture depends on the resolution setting you have on your (digital) camera. Typically, the default settings for most cheaper digital cameras take photographs which would print out (at 100%) at about A3-size. This can be upped on your camera. Once you shrink a photograph (in size and in quality) you cannot blow up the same picture without losing some of the quality that existed in the original. Programmes that claim to lose no quality when blowing up photographs are only patching over lower resolution pixelations.

[Cetti]

What's that in English, Indie? :-)

Seriously, with IrfanView I don't have any problem with enlarging - I crop and enlarge  all the time. Perhaps it helps as my  digital camera is 5 million, but  as long as the original picture is perfect I don't see the problem.

[Potatoman]

Idiesinger is dead right - An expanded pic wont look as good as the original

[Potatoman]

Taking into account what cetti said, it would depend on how big you enlarge.

[IndieSinger]

Hmm, does it make sense if I say that when enlarging a picture, a computer programme can only ever enlarge existing pixels? For an optimum-quality picture, the programme would somehow need to intelligently place many correct smaller pixels in the place of the enlarged one.

Say, just for instance, you have a square. This square is made up of 5 blocks x 5 blocks ("pixels"). These blocks alternate between being blue and red. Here's the square at 100% of it's size (it's original size).

▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓

Now, if you were to shrink this picture so that is was just one block by one block, it would look like this:

▓

... because the red and blue pixels have combined to make (what our eyes see as) purple.

[IndieSinger]

Once you've shrunk this picture (as I said before, in size and in quality) so that you have the square above, any attempts to enlarge it again will be poorer quality. The computer only knows what's there - all it can see is one purple pixel. So, if you wanted to enlarge it to 5 blocks by 5 blocks again, it would simply stretch that pixel to your deisred size and would create this:

▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓

... which, in terms of your photograph, means lower quality as there is much less detail.

If this post has worked, it'll be a miracle.

[IndieSinger]

OK so the number 619 won't automatically appear in your photo. Let's try that last diagram again:

▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓
▓▓▓▓▓

[IndieSinger]

No clue where that number's appearing from. It's the same as the first diagram, but all purple.

[Ralph]

IndieSinger, what you are saying is obviously wrong because I saw CSI Miami where they took a CCTV photo with a car in the background, zoomed into the number plate which was 1 pixel by 1 pixel in the original photo, then they refined it to show the reflection of the perpetrator in the number plate. I saw this on tv, so it must be true.

I'm only joking before I get flamed to death, but it is tv shows such as this that leads people to believe that you can do things like this. If the detail isn't in the original photo, the computer cannot recreate it.

I'm off to access the blueprints of my local bank online with a computer (probably a mac) that doesn't need a mouse and beeps at every key stroke. Ahhhh, tv.