h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

I have a picture that I use as a signature on a couple of sites. The picture is 600 pixels x 150 pixels. That's about 16cm x 4cm, or 6.25in x 1.5in if you prefer non-metric. I've been told it would make a great poster, and I agree. But how do I convert such a small image to a decent sized poster. Obviously just zooming in won't work as it would become pixellated.

I assume I need a decent editing package - I have Photoshop 6. Or do I just ask some print shop to do it for me?

Traveller in Time on the drawing board
"Depends on what kind of image it is.

Photographs are difficult to enlarge excessively, resize it with a prime factor (eg 4cm >> 7cm) enhance the image and again.

Drawings (cartoons / clipart) are the most straightforward, some can be scaled up infinitely without any loss.
Some have to be convert to a vector drawing before they can be scaled. "

look for the sharpening tool

It's hard to describe the image. It's a drawing/painting of a dragon combined with a photograph of somebody. The two have been skillfully merged/blended - but not by me. I don't have those skills.

I'll try to find the sharpening tool on Photoshop. It may be a case of playing with the picture.

Traveller in Time on top
"Is it the orange/yellow serpent-dragon ?

Try to enlarge it step by step "

This is it. http://i117.photobucket.com/albums/o41/CheerfulDragon/Stargate/dragonbaal.jpg

I don't know what you mean by 'step-by-step'. Do you mean in small increments, like 50 pixels?

Traveller in Time hiding behind a rock
"That is an option, what I do mean is to scale it up in several steps.
Current 600px width, first step _not_ to 1200px but say to something like 1111px, this will blur the digital defects. Then enhance the image to your liking, this can involve blurring it a little, the most significant defect will be pixelisation (visible squares).

Then second step to 2000px, just to make sure the magnification does not generate defects.

(Just did something like that and the result is not bad at all )"

Um. I'm not at all sure what I'm doing here, so it's probably best if I leave well alone. I'll have to find somebody to do it for me. Thanks for your help, anyway.

> The picture is 600 pixels x 150 pixels.

That's a whopping great signature file! But rather small for anything other than printing small(ish) size. If you got it from someone else, it's possible it was reduced from a larger version anyway and it might be worth going back to them to ask.

Otherwise my next approach would be to write some custom software to do a degree of interpolation on sizing up (which would make it fuzzy rather than pixellated but might be worth trying anyway). Is it in JPG or GIF (or BMP) format or something else?

Actually, in printing terms, that image would be something like 2-3 inches wide only as printing usually takes images of 300 dpi (dots or pixels per inch)...

I would guess that blowing up an image that size to a poster would be very difficult without ending with something coarse.

Do oyu have any way of getting to the original artwork file? - I'd guess that it was scaled down to generate the small image.

How big a poster would you like to make?
As SEF and Santragenius V say 600x150pixels is small in printed image terms. At best you'll get something 2x0.5inches that you can look at like a photo or something bigger that you can look at from further away.

If you don't want to roll your own software, then something like Genuine Fractals can interpolate up your picture to bigger sizes or you can do a similar thing by increasing the size in small amounts (eg +1%) lots of times in photoshop or similar.

The best option is to see if whoever did the banner for you has a larger version that would scale up better or be the right size to start with.