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The Chip Board Archive 08

Re: A Technological Discussion of Scanning
In Response To: A Beautiful New Chip ()

Dots Per Inch (DPI) is only a meaningful metric on the printed page. It's irrelevant on the computer screen. a 17 inch monitor set up for 1024 by 768 dots (called pixels in monitor-speak) on the screen will have more "dots per inch" than a 21 inch monitor set to the same resolution, or the same monitor set to a higher resolution. What matters on the computer screen is how many pixels wide by how many pixels high the image is.

That said, the way a scanner program controls the number of pixels in an image is through the "DPI" setting. I happen to like my chips at 150 DPI, which produces an image 250 by 250 pixels. Your image above is 404 by 412 pixels, but you have a lot of extra blank space around the chip. By looking at the image properties, I can see you are scanning at 200 DPI.

There are three components you can control that affect file size: number of bits per pixel (color depth), total number of pixels, and compression level. I wouldn't mess with the color depth. You are at 24 bits, or 3 bytes per pixel, which is pretty standard. Less than that and you lose the range of colors you can reproduce.

I'd suggest you scan at something between 120 and 150 DPI. Personally, I don't like the loss of detail that occurs below 120 DPI. But then the images on Greg's Chip Guide are all at 100 DPI. I've done surveys on the board here, and the opinions are all over. Go with what you like. My image below is 150 DPI. I'd also crop a little closer to the chip. All that gray has to go in the file somewhere.

Compression is the main setting you need to adjust. Unfortunately, it's the hardest to determine the best compromise. Without compression, your 404 by 412 image above would consume 499,344 bytes. JPG is a good, common compression scheme, but it is "lossy." That means the more you compress, the more detail you lose. When I reduced the file size on your Saddle West chip, all I did was compress it more. I couldn't tell the difference in image quality when I was done. I use a "medium" compression level in Photoshop. I don't know how to relate that to whatever settings you have available in your tools. I'd suggest you find your compression level adjustment and experiment. You're looking for a nice compromise between file size and image quality. Good luck!

Messages In This Thread

A Beautiful New Chip
Re: A Beautiful New Chip
Re: A Beautiful New Chip
Re: A Technological Discussion of Scanning
Beautiful!
So I owe two people?
Re: So I owe two people?
Re: Chip Dimension
Re: Chip Dimension

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