Re: [Gimp-user] Optimize jpegs

2014-05-23 Thread Jernej Simončič
On Thu, 22 May 2014 02:20:31 +0200, weswood wrote:

 What do you think is
 the best setting to bring down the file size with no noticeable loss of 
 quality?

95 is the maximum you should use - there's no perceptual difference between
95 and 100, but the size increase is huge.

Anyway, with most images you can go even lower - when exporting a JPEG,
tick the Preview checkbox, and play with the settings. You should always
enable both Progressive and Optimize, as those losslessly reduce the file
size, and switch the DCT mode to Floating point (slightly improves quality,
and usually reduces the file size). Try also different subsampling options
- depending on image content, you can get quite a size reduction while
having very little visual difference.

-- 
 Jernej Simončič  http://eternallybored.org/ 

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Re: [Gimp-user] Optimize jpegs

2014-05-22 Thread Søren Pilgård
On Thu, May 22, 2014 at 2:30 AM, Owen rc...@pcug.org.au wrote:

 I'm creating some textures for 3d models using gimp.  I've been
 exporting as jpg
 with quality set at 100, but the file sizes are humongous.  What do
 you think is
 the best setting to bring down the file size with no noticeable loss
 of quality?





 Well, I would simply experiment and decide what is best for you

 Open original, export as new-name1.jpg at say 70%
 Then reopen original, and export as new-name2.jpg at say 60%
 and so on

 Most of my saves are at 50%

 Why jpgs? What sizes do you get with pngs?


It is indeed hard to give a perfect number out of the box.
The overall visual quality is very much dependent on what the image
actually depicts and on what kind of compromise you can tolerate.
A dirt texture can probably pull off a much lower quality than a
smooth gradient.
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Re: [Gimp-user] Optimize jpegs

2014-05-22 Thread Gary Aitken
On 05/22/14 07:08, Søren Pilgård wrote:
 On Thu, May 22, 2014 at 2:30 AM, Owen rc...@pcug.org.au wrote:

 I'm creating some textures for 3d models using gimp.  I've been
 exporting as jpg
 with quality set at 100, but the file sizes are humongous.  What do
 you think is
 the best setting to bring down the file size with no noticeable loss
 of quality?





 Well, I would simply experiment and decide what is best for you

 Open original, export as new-name1.jpg at say 70%
 Then reopen original, and export as new-name2.jpg at say 60%
 and so on

 Most of my saves are at 50%

 Why jpgs? What sizes do you get with pngs?


 It is indeed hard to give a perfect number out of the box.
 The overall visual quality is very much dependent on what the image
 actually depicts and on what kind of compromise you can tolerate.
 A dirt texture can probably pull off a much lower quality than a
 smooth gradient.

First, make sure the image is down-sized to something like 1280 x 1024 or
less.  Then turn on the preview in the jpeg export dialog.  That will tell
you both how large the file will be, and you can view the preview to see
what it will look like.  Decrease or increase the percentage until you're
happy with the compromise.

Gary
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[Gimp-user] Optimize jpegs

2014-05-22 Thread weswood
First, make sure the image is down-sized to something like 1280 x 1024
or
less.  Then turn on the preview in the jpeg export dialog.  That will
tell
you both how large the file will be, and you can view the preview to
see
what it will look like.  Decrease or increase the percentage until
you're
happy with the compromise.

Gary

Thanks, I'll try all these suggestions.  This one was very helpful, at least
I'll see what I'm getting.

-- 
weswood (via www.gimpusers.com/forums)
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[Gimp-user] Optimize jpegs

2014-05-21 Thread weswood
I'm creating some textures for 3d models using gimp.  I've been exporting as jpg
with quality set at 100, but the file sizes are humongous.  What do you think is
the best setting to bring down the file size with no noticeable loss of quality?

-- 
weswood (via www.gimpusers.com/forums)
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Re: [Gimp-user] Optimize jpegs

2014-05-21 Thread Owen

 I'm creating some textures for 3d models using gimp.  I've been
 exporting as jpg
 with quality set at 100, but the file sizes are humongous.  What do
 you think is
 the best setting to bring down the file size with no noticeable loss
 of quality?





Well, I would simply experiment and decide what is best for you

Open original, export as new-name1.jpg at say 70%
Then reopen original, and export as new-name2.jpg at say 60%
and so on

Most of my saves are at 50%

Why jpgs? What sizes do you get with pngs?



-- 
Owen

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