People,
I am trying to work out why there is such a large file increase when I
edit a file and save it. The background info:
Original file (from digital camera) - format, size, depth, geom:
JPEG 680590 8 2048x1536
After opening and saving original file with defaults (85% quality):
JP
Hi Philip,
On 15 Jan 10 10:56 Philip Rhoades said:
> - When saving as JPG with 85% quality am I losing information?
Yes!
> - How can saving as JPG with 100% quality increase information (file
> size)?
It doesn't throw so much info away. It's not actually bigger than the
the raw data (i.e. to
Hi Philip,
Philip Rhoades wrote:
> - When saving as JPG with 85% quality am I losing information?
JPG utilizes lossy compression, which means you'll loose information
every time you save as JPG, even at 100% quality setting.
That value does not specify the percentage of information stored
in th
People,
On 2010-01-15 23:33, yahvuu wrote:
> Hi Philip,
>
>
> Philip Rhoades wrote:
>> - When saving as JPG with 85% quality am I losing information?
>
> JPG utilizes lossy compression, which means you'll loose information
> every time you save as JPG, even at 100% quality setting.
>
> That value
Philip Rhoades wrote:
> What still doesn't make sense is that if the original file is JPG and
> one simply opens it and then saves it as another JPG file with 100%
> quality - you are saying that introduced artifacts are adding about 150%
> to the file size? (681 KB to 1.618 MB) How could the compr
On Fri, 15 Jan 2010 21:56:40 +1100, Philip Rhoades wrote:
> - Why is PNG so inefficient?
PNG is not efficient for real life images (ordinary photos).
PNG is very efficient for computer generated images (like a snaphot of
a program window, or a relatively simple paint, or vector graphics, or
some
Hi Philip,
On 15 Jan 10 12:53 Philip Rhoades said:
> What still doesn't make sense is that if the original file is JPG
> and one simply opens it and then saves it as another JPG file with
> 100% quality - you are saying that introduced artifacts are adding
> about 150% to the file size? (681 K
On Fri, Jan 15, 2010 at 4:56 AM, Philip Rhoades wrote:
> People,
>
> I am trying to work out why there is such a large file increase when I
> edit a file and save it. The background info:
Google the difference between "lossy" and "lossless" image
compression. Once you understand the fundamental
People,
On 2010-01-16 00:11, yahvuu wrote:
> Philip Rhoades wrote:
>> What still doesn't make sense is that if the original file is JPG and
>> one simply opens it and then saves it as another JPG file with 100%
>> quality - you are saying that introduced artifacts are adding about 150%
>> to the
Philip Rhoades writes:
> What still doesn't make sense is that if the original file is JPG and
> one simply opens it and then saves it as another JPG file with 100%
Because JPEG isn't meant to be saved at 100% quality.
The JPEG FAQ, http://www.faqs.org/faqs/jpeg-faq/part1/section-5.html, says:
Hi Philip,
On 15 Jan 10 18:27 Philip Rhoades said:
> - when the JPG is uncompressed by GIMP into RAM, there is no loss of
> information (?)
No further loss, but the restored image is subject to those averages
created when the image was originally compressed.
> - when GIMP then saves the same
On Fri, Jan 15, 2010 at 12:27 PM, Philip Rhoades wrote:
> - there was a loss of information when the first JPG was saved in the
> digital camera memory from the CCD
Correct
> - when the JPG is uncompressed by GIMP into RAM, there is no loss of
> information (?)
Since JPG is not lossless, there
Hi,
On Sat, 2010-01-16 at 05:27 +1100, Philip Rhoades wrote:
> I guess what is confusing is this:
>
> - there was a loss of information when the first JPG was saved in the
> digital camera memory from the CCD
>
> - when the JPG is uncompressed by GIMP into RAM, there is no loss of
> informati
Actually, you get almost no further degradation if you save the image
> again with the same settings that were used for the first save. The JPEG
> plug-in even stores information in the image when the image is opened
> and it will use that information to save it in the best possible way
> when you
On Fri, 15 Jan 2010 21:56:40 +1100, Philip Rhoades wrote:
> - When saving as JPG with 85% quality am I losing information?
Yes, but still with the same 85% quality you may obtain different
results by changing other parameters.
Just look at the following example. Note the file size for each, but
On 15.01.2010 19:59, Greg Chapman wrote:
>> - when GIMP then saves the same image as a new JPG at 100% quality
>> (I would have thought that this meant not losing any more
>> information),
>
> You shouldn't take 100% too literally.
Especially if the value is not a percentage.
Regards,
Michae
Frank Gore píše v Čt 14. 01. 2010 v 21:35 -0500:
> Sorry, those were links to the version of the pictures as displayed by
> Picasa, which has the metadata stripped. The direct download links are
> as follows:
>
I thought your camera would be very unusual to provide JPEGs w/o
metadata...
> Adobe R
Frank Gore píše v St 13. 01. 2010 v 18:20 -0500:
>
> In any case, like I mentioned in my original post, I specifically have
> it set to "Ask what to do" in the Preferences, and it doesn't ask.
>
I agree with you, it is definitely a bug. GIMP should not assume that
JPEG is in sRGB colour space whe
On Fri, 2010-01-15 at 13:32 -0600, Paul Hartman wrote:
> On Fri, Jan 15, 2010 at 12:27 PM, Philip Rhoades wrote:
> > - when the JPG is uncompressed by GIMP into RAM, there is no loss of
> > information (?)
>
> Since JPG is not lossless, there is always a loss of information. Or
> more specifical
On Sat, 16 Jan 2010 10:54:23 +1100, David Hodson wrote:
> I'm fairly sure this is not true - there is only one way to uncompress a
> JPG file, so all programs should create the same uncompressed version.
Not true - I know that at least different versions of ImageMagick will
decompress the same JP
On Fri, Jan 15, 2010 at 5:54 PM, David Hodson wrote:
> On Fri, 2010-01-15 at 13:32 -0600, Paul Hartman wrote:
>> On Fri, Jan 15, 2010 at 12:27 PM, Philip Rhoades wrote:
>
>> > - when the JPG is uncompressed by GIMP into RAM, there is no loss of
>> > information (?)
>>
>> Since JPG is not lossless
Philip Rhoades wrote:
> I am trying to work out why there is such a large file increase when I
> edit a file and save it. The background info:
>
> Original file (from digital camera) - format, size, depth, geom:
>
> JPEG 680590 8 2048x1536
[..]
> After opening, cropping and saving or
On Fri, 2010-01-15 at 18:07 -0600, Paul Hartman wrote:
> On Fri, Jan 15, 2010 at 5:54 PM, David Hodson wrote:
> > On Fri, 2010-01-15 at 13:32 -0600, Paul Hartman wrote:
> >> [...] the same JPG can be interpreted differently by
> >> different software, so opening it in GIMP might look different th
Bob,
On 2010-01-16 11:32, Bob Long wrote:
> Philip Rhoades wrote:
>
>> I am trying to work out why there is such a large file increase when I
>> edit a file and save it. The background info:
>>
>> Original file (from digital camera) - format, size, depth, geom:
>>
>> JPEG 680590 8 2048x1
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