Does anyone know of a portable program that does what paint.net does in terms of dithering on PNG files?
The idea is that the gradients in a given image don't turn into separate, distinct blocks but instead still blend somewhat and produce low file sizes. RIOT tends to do the blocky thing (which you may have seen in several of my screencaps) where Paint.NET does the smooth, dithering thing.
See below for a screencap of the Paint.NET dialog on this:
Dithering in PNG files?
Re: Dithering in PNG files?
Dithering hurts compression ratio really badly. If you want gradients to blend, just use enough colors. If not, let gradients turn into blocks.webfork wrote: The idea is that the gradients in a given image don't turn into separate, distinct blocks but instead still blend somewhat and produce low file sizes.
My YouTube channel | Release date of my 13th playlist: August 24, 2020
Re: Dithering in PNG files?
Are you sure? I just ran a standard test (random screenshot) in Paint.NET using 8-bit color and mid-range dithering that came out to only 34k where if I bumped up to 24-bit color, the file size goes up to 63k. Is dithering really that bad?
Re: Dithering in PNG files?
Okay, I ran a test as well. I captured a screenshot when I viewed your post and saved it as PNG with Snipping Tool. The file was 253 kilobytes large and contained 19 435 colors.webfork wrote:Are you sure? I just ran a standard test (random screenshot) in Paint.NET using 8-bit color and mid-range dithering that came out to only 34k where if I bumped up to 24-bit color, the file size goes up to 63k. Is dithering really that bad?
Then I converted the picture to indexed color mode. I converted it with GIMP. I let it generate optimized palette of 255 colors and turned dithering off. The resulting file was 64 kilobytes.
Finally, I converted the original picture to indexed color mode again. Again, I used GIMP and allowed it to generate an optimized palette of 255 colors. This time I used Floyd-Steinberg dithering. The resulting file size was 546 kilobytes, i.e. over twice as large as the original picture!
My YouTube channel | Release date of my 13th playlist: August 24, 2020
Re: Dithering in PNG files?
Okay I'll recheck using GIMP. Thanks for testing.SYSTEM wrote:Then I converted the picture to indexed color mode. I converted it with GIMP. I let it generate optimized palette of 255 colors and turned dithering off. The resulting file was 64 kilobytes.
Re: Dithering in PNG files?
Unless you have jumbled up your units (eg kilobits vs kilobytes), my math skills tell me that 546/64=8. Technically, you are correct in saying that is over twice as large, but your are understating it quite a bit.SYSTEM wrote:Then I converted the picture to indexed color mode. I converted it with GIMP. I let it generate optimized palette of 255 colors and turned dithering off. The resulting file was 64 kilobytes.
Finally, I converted the original picture to indexed color mode again. Again, I used GIMP and allowed it to generate an optimized palette of 255 colors. This time I used Floyd-Steinberg dithering. The resulting file size was 546 kilobytes, i.e. over twice as large as the original picture!
Re: Dithering in PNG files?
I said "over twice as large as the original picture" which was 253 kilobytes large.romulous wrote:Unless you have jumbled up your units (eg kilobits vs kilobytes), my math skills tell me that 546/64=8. Technically, you are correct in saying that is over twice as large, but your are understating it quite a bit.SYSTEM wrote:Then I converted the picture to indexed color mode. I converted it with GIMP. I let it generate optimized palette of 255 colors and turned dithering off. The resulting file was 64 kilobytes.
Finally, I converted the original picture to indexed color mode again. Again, I used GIMP and allowed it to generate an optimized palette of 255 colors. This time I used Floyd-Steinberg dithering. The resulting file size was 546 kilobytes, i.e. over twice as large as the original picture!
My YouTube channel | Release date of my 13th playlist: August 24, 2020
Re: Dithering in PNG files?
Fair enough, I thought the whole point of the exercise was to compare dithered (546KB) vs non-dithered (64KB). I was mistaken obviously.
Re: Dithering in PNG files?
Not the whole point, just a part of the point.romulous wrote:Fair enough, I thought the whole point of the exercise was to compare dithered (546KB) vs non-dithered (64KB). I was mistaken obviously.
There are three options regarding image quality and file size:
- 24-bit colors: highest quality, but relatively large
- indexed colors, not dithered: lowest quality, but also smallest file size
- indexed colors, dithered: quality somewhere in between. Also relatively large.
It only added an insult to the injury that "indexed colors, dithered" was also larger than "24-bit colors" with my test sample. Dithering that picture makes no sense at all, because the original picture is both smaller and of higher quality.
My YouTube channel | Release date of my 13th playlist: August 24, 2020
Re: Dithering in PNG files?
Right, now I understand
Now that causes my eyebrow to raise! Would never have predicted that - would have always went for the 'full 24bit will always be larger' option.SYSTEM wrote:It only added an insult to the injury that "indexed colors, dithered" was also larger than "24-bit colors" with my test sample.