about /screenshot lossless

[bilbous]

Looking on the pswiki I see that this is supposedly without compression, is that a mistake as PNG supports compression (losslessly), is there some way to specify compression level, or is it just as it says?

[ThomPhoenix]

You get better quality, but the file size is also bigger.

[Manar]

They're definitly compressed, otherwise the lossless screenshots would be megabytes in size.
I never take lossy screenshots... if necessary it's easy enough to convert afterwards.

[bilbous]

Then it is an error on the wiki as I suspected. That is all I wanted to know.

and the "lossless" option can be used to save without compression to PNG instead of JPG.

here

[Nikodemus]

png is compressed file format, only the compression doesnt make to loose details, thus is called lossless compression. Its always the same compression, as good as possible, without loosing details of the image.
with jpg you can manipulate with the compression and thus have less or more lost details.

[bilbous]

Png supports variable compression rates all of which are lossless, it is a lossless standard. Anyway, I've gone ahead and corrected the pswiki page which was my main purpose in starting this thread. 

[Nikodemus]

whats the point of using different compression if every is lossless but one is worse than another?

[Raleigh]

whats the point of using different compression if every is lossless but one is worse than another?

When I can convert an image to .gif without losing too much quality, I go for it. Otherwise I prefer .png over .jpg simply because I really use lots of transparency when I make images and .jpg doesn't support transparent backgrounds.

[Nikodemus]

you do realise png is always, always and always better than gif? Unless you wish to have one color transparent while having 256 colors.

you didn't realy answer my question, but it doesnt matter.

[bilbous]

whats the point of using different compression if every is lossless but one is worse than another?

The difference is the speed of the compressing, it is similar to zips or rars, the more you compress the longer it takes the algorithms to complete. For my part I usually compress png's maximally though if I was working on gigabit sized images with limited processing power I might choose  a lesser compression rate. The JPG standard also allows for no compression and there is an extension, jpg2000 (I believe) still covered by patents which allows for lossless compression as well. PNG is open source but typically does not perform well for photo quality images.

[Raleigh]

you do realise png is always, always and always better than gif? Unless you wish to have one color transparent while having 256 colors.

you didn't realy answer my question, but it doesnt matter.

     That was exactly what I was referring about. I  Use .gif only for images that still look good on 256 colors + transparency.

whats the point of using different compression if every is lossless but one is worse than another?

The difference is the speed of the compressing, it is similar to zips or rars, the more you compress the longer it takes the algorithms to complete. For my part I usually compress png's maximally though if I was working on gigabit sized images with limited processing power I might choose  a lesser compression rate. The JPG standard also allows for no compression and there is an extension, jpg2000 (I believe) still covered by patents which allows for lossless compression as well. PNG is open source but typically does not perform well for photo quality images.

"If I was working with gigabit sized". Only people who work with such sizes of images are probably those inside organizations like NORAD and NASA, as really high resolution maps of Earth or other planets. But such images don't require much photoshopping.

[bilbous]

I don't know, try scanning a 5"x4" negative at 9600 resolution and see how big it is. Lets see that would make it 48,000x38,000 pixels or 1.8432 billion pixels then *24 bits per pixel would be about 44 gigabits or ~5 GB, suitable for fine arts reproductions and then you need to remove scanning artifacts. Certainly would not like to use jpg but you might use tiff instead of png. Of course tiff doesn't compress...