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Post by Vermin King on Oct 22, 2015 17:30:07 GMT -9
I don't know why sometimes, doing little things in Gimp seems to exponentially increase the file size. Other times, not so much. I thought it was just one of the hazards of using this program.
When I cleaned up the carriage house, it ended up about 5 times the original file size. When I did those mods on Mauther's two-story stone house, they ended up 10 times larger. Cleaning up the roman chariot did little to the file size, and all the changes for the Dwarf chariot only increased the size by 20%. Not bad at all
Today, I wanted to mod the Fitz forge to fit in with the Mauther buildings. When I compared the maximum wall height to other structures, I realized this was too small. I opened two new pages and copied over the parts between the two documents. Did not even enlarge yet, and all of a sudden I had taken a one-page document at 121 KB, and turned it into two 1 MB documents. Upon enlarging, I was up to 1.4 MB on one and 1.8 MB on the other.
Is there any way to keep this from happening at such an alarming rate?
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Post by bravesirkevin on Oct 23, 2015 0:57:10 GMT -9
It's mostly to do with compression. Normally with an A4/US Letter sized page at 300dpi you'd actually expect it to be about 30mb for a single, flat, uncompressed image. It's actually quite common for my raw artwork to be in the hundreds of mb range just because I tend to use a lot of layers.
Now, something you've downloaded off the net typically has quite a lot of compression on it and JPEG compression is quite ruthlessly efficient at crushing things down. It's quite possible to shrink a file down to well less than a 10th of it's original size, especially if you don't mind the loss in quality. When resaving, you're generally going to save in an uncompressed format in order to prevent an accumulation of compression artifacts from progressively degrading the quality to a point where the new version is unusable, and that might go a long way towards explaining the bigger shifts in file size.
Other factors may include: • Internet files usually have metadata stripped. Resaving puts the metadata back. This would usually amount to a few hundred kb at most. • Resizing. Doubling the height and width of a file means quadrupling the number of pixels in it, so you'd have 4 times the file size. • More detail. Flat colours compress quite well with JPG and PNG compression. if your new version has replaced a flat colour with a texture, when you recompress it's not going to squash it down as efficiently, so your new compressed file is still going to be bigger than the old one.
In short, the answer is that it's natural so you shouldn't be too alarmed by it. You should generally keep uncompressed versions of any work you do, so expect lots of really big files. For the purposes of distributing, compression becomes a lot more important, but you should always handle that sort of optimisation on a case-by-case basis because you want the best quality you can get for the smallest file size, and that's going to vary greatly from file to file.
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Post by hackbarth on Oct 25, 2015 18:31:21 GMT -9
You have to understand how image compression algorithms work. Or at least what they are doing. If the image is composed of few colors, have many areas with plain colors, without degrades and complex patterns, like A comic book, or like Okumarts figures, PNGs may be the better extension. If the figure has photo realistic patterns or smooth transitions and degrades, JPGs may be the better choice.
It may happen that someone saved a file that would be better as a PNG in JPG format, then the damage is done, saving in PNG wouldn't get the same compression after that.
Ad there a number of things you can do knowing how to do them. Like limiting the number of colors (less colors compress better in PNG), messing with the borders of the figure (smooth borders should compress better than starly defined ones_in JPG)
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Post by Vermin King on Oct 31, 2015 8:56:10 GMT -9
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