Re: [applekeynote] Scaling

Hi,

I haven’t picked up ‘09 yet, so I do not know “how” blurry you are seeing, but anytime you upscale an image, there’s going to be some level of blurring. Increasing the size of an image, even in Photoshop, has varying degrees of success and the greater the up-scaling, the greater the blurring is going to be. In addition, the smaller the size of the original image, the greater the blurring will be even if doing the same percentage on the same image. That is, if you have the same image at 2000 pixels across and at 200 pixels apart and you expand them to 3000 and 300 respectively, the smaller will display much greater blurring.

Hmm, I just saw Brian saying that there is some bug in iWork. There may be, but again, I do not know how much blurryness you are seeing and I do not how much of that is iWork and how much of that is optic physics.

Remember, what you see on CSI is NOT POSSIBLE. When the computer guy takes an image from a surveillance camera, taps a few keys on the computer and blows up the image so you can see the license plate on the car across the street. It’s great TV, but it’s lousy optic science. [Note: despite my chuckles at this, I do enjoy CSI and watch it each week.]

There are plugin software solutions for this such as Blowup (by Alien Software) and Genuine Fractals (by OnOne software). What these products do is to find the edges within the image, turn them into vectors so the edges do not pixelate when the image is enlarged and then rasterizes the vectors at the end of the process. Unfortunately this often leads to lack of artifacts in those regions that tend to make the image look rather plastic-like. In the past couple of years the software companies have introduced noise artifacts in the image to limit this and the results are getting better.

Downscaling is always going to be successful (some of the possible side effects tend to be a slight darkening of the image, but that’s about it).

Ergo, the best solution to upscaling is to not do it in the first place. See if you can find an image that is larger than you need and decrease it in size.

I hate to be a spoil-sport here, but your question is excellent and is one of the most often asked questions when I do any Photoshop seminar (other than “why do my printed images not look like they do on the screen?”)

Best,

Gary C


On 1/23/09 10:57 AM, "alsivan" <alsivan@terra.com.pe> wrote:

 

Hi! I am trying to scale an image to 150%, but the scaled image turns out blurry, even when I use a good quality picture. Any ideas
how to keep the quality of the enlarged image?

Ivan

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