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Creation Date: 2003-01-08
I didn't finish "Javantea's Guide for Technophobes". Oh well. I did do two mini murals for wrapping of two other presents. Christmas isn't about presents in case you didn't hear that ten thousand times before now. I'm getting along with my dad this Christmas. We argue, but that's cool. If we didn't, we'd be lying to ourselves and each other. We disagree on many issues. He is intelligent, so his arguments are interesting. He doesn't swallow what he hears on the TV hook, line, and sinker. Certainly that's a sign of hope.

I'm watching a movie called Duets that shows an interesting light on people who are living the American Nightmare in a very interesting way: karaoke. It doesn't matter so much that they are singing karaoke, but that they have skill, that they have serious social problems, and that they are finding nature's solution: life.

Merry Christmas.

what is this picture? I drew it yesterday for fun. It was a half-decent picture. Sadly, my paper is very textury so it compresses poorly so both the High and Low bandwidth versions look awful. They're both low bandwidth, but at the price of the original picture. Neither of these represent the true original picture. However, they both represent what I planned for the lesson today. The jpeg version explains the nature of lossy compression using a mathematical algorhithm based on matricies. Those boxes you see are a byproduct of the algorhithm. In high-quality jpegs you miss it because the boxes are smaller than the pixel. However... jpeg almost never produces a lossless reproduction of an original image. Even when it's not compressing at all, it is not lossless. However, jpeg can create visually undistinquishable pictures from photographs. It is important that jpeg can do both low quality photographs and high quality photographs to allow for different uses. People that wish to send a digital photo to friends or relatives via e-mail can compress it highly for quick upload/download. Most amateur have some photos on their personal website given to them by their ISP (10 MB or so) in the medium quality. Professionals can transfer high resolution and medium quality jpegs for professional use. News websites can have a bunch of small JPEGs at medium quality for quick consumption. Jpeg does not work well with large pictures. If you double the scale of a photo, the jpeg does not stay the original size, it will increase while displaying very little extra information. Jpeg certainly does geometric images poorly. Vector graphics is very fuzzy and very large in jpeg format. The problem is that the jpeg algorhithm relies on small changes over a small position change. The major change in jpeg is color. Color information is reduced from 16 bits to 8 bits while luminosity remains 8 bits. With jpeg compression, you simply lose color information. On a greyscale image, you don't lose color, but you don't gain compression from it.

PNG compression on the other hand is lossless. But that doesn't mean that the PNG picture featured here is lossless from the original. The PNG version of this has been severely changed towards less information. Sadly, after trying in Adobe Photoshop (my father's program) to reduce noise without losing information, I gave up at this point. It is far more compressed than most of the others and retains most of the information. You see, the paper I used to draw this had a texture to it. So when I scanned it, the texture was in the image. It is so random a pattern that the PNG algorhithm could not deduce it. So I wanted to get rid of it. My idea was that the pattern was light colored. Thus, I could simply wash out the lighter colors by adding white to all colors. That worked half way. Then I took the lightest 20 colors and deleted them to white. The problem was that I lost part of the knees. I decided that I didn't care so much. Then I tried to darken all the rest. That is not as easy as it seems. If I darken it too much, it looks awful, pixellated even. If I don't darken enough, it looks washed out and is too light to see. But to be between too dark and too light makes it even worse. The solution? Be too light. I hate to put work into something to make it look roughly drawn and have it look pixellated. It compressed well with PNG without the texture. That is what I wanted.

That is the solution to your problem. What? That. How is that a solution? It gives you enough information to make a decision. If you have a photo, compress to your liking with jpeg. If you have a vector graphic, compress with png. If you need both, try to blur your vector graphic for jpeg. Try to delete unuseful information. A photo compressed with png is hopeless. Scale it down to small as you can. If you want lossless, you need png.
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