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uploaded photos out of focus and with wrong color

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發表於 2014-3-18 17:45:35 | 顯示全部樓層 |閱讀模式
Hi Admin,

The compressed versions of uploaded photos are out of focus and with wrong color.  Clicking on the photos to see the 2MB files show the correct pictures.

Is there any way to improve the compressed files which can be viewed instantly?

Thanks for looking into this.

Vincecharus

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發表於 2014-3-18 22:17:01 | 顯示全部樓層
do you have a link of the problematic photos?
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 樓主| 發表於 2014-3-18 22:26:27 | 顯示全部樓層
Jason 發表於 2014-3-18 22:17
do you have a link of the problematic photos?

Jason:

My threads "A few street shots" and "Today's test shots"

thx!

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發表於 2014-3-18 23:43:10 | 顯示全部樓層
i checked. i think the problems you mentioned is actually unavoidable. There might be some artifacts during resizing, especially using the engine in discuz. its quality certainly cannot be as good as using lightroom's engine, etc. so probably some inaccuracies can't be avoided
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 樓主| 發表於 2014-3-19 00:29:06 | 顯示全部樓層
Jason 發表於 2014-3-18 23:43
i checked. i think the problems you mentioned is actually unavoidable. There might be some artifacts ...

Noted with thx
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發表於 2014-3-19 00:48:04 | 顯示全部樓層

we are now exploring the possibility to improve it.

but we will have to see if it works

點評

It just messed up my iphone pic. Pls have a look!  發表於 2014-3-21 14:59
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 樓主| 發表於 2014-3-21 14:53:53 | 顯示全部樓層
Jason:

Thx for looking into this.  Think about it, could you guys please do something about it coz the compression algorithm doesn't even do an iphone pic right!

Have a look at this:

http://www.mclassic.com.hk/forum ... &extra=page%3D1
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發表於 2014-3-21 15:43:20 | 顯示全部樓層
vincecharus 發表於 2014-3-21 14:53
Jason:

Thx for looking into this.  Think about it, could you guys please do something about it coz  ...

actually i don't see a significant problem in the compressed pic.

you mean the color or sharpness?? and what browser do you use?

點評

I'd say the same about most other ppl's pics.  發表於 2014-3-21 16:13
Firefox 27. On my monitor (Dell U3011) both color and sharpness are way off!  發表於 2014-3-21 16:10
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發表於 2014-3-21 16:29:19 | 顯示全部樓層
Attached is a screen capture of the compressed pic (left) and the downloaded original pic (right).

I don't see a significant color shift. The compressed pic is a little bit less sharp and with less dynamic range (most noticeable on the flowers), but it is normal. The compressed pic is 130K, the original one is 1.9MB. It is more than 10 times of stored information!!

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發表於 2014-3-21 16:31:00 | 顯示全部樓層
vincecharus:

would you screen cap the problematic image along with the full size one, so that we can see how off the color is?
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 樓主| 發表於 2014-3-21 16:38:19 | 顯示全部樓層
本帖最後由 vincecharus 於 2014-3-21 16:42 編輯
Jason 發表於 2014-3-21 16:31
vincecharus:

would you screen cap the problematic image along with the full size one, so that we ca ...

These are screen shots made by the Windows scissors tool.  Even though the screen shots themselves suffer from bad compression, you can see some of the degree of difference!

first one is compressed, second one uploaded


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 樓主| 發表於 2014-3-21 16:41:12 | 顯示全部樓層
first one is compressed, second one uploaded

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發表於 2014-3-21 16:43:24 | 顯示全部樓層
then it should be your computer setting problem.

please go through this:
http://www.gballard.net/psd/go_l ... edJPEGprofiles.html

and it is not just browser setting, but the color space of the image you export. I think you have chosen AdobeRGB, but you should choose sRGB

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 樓主| 發表於 2014-3-21 17:00:41 | 顯示全部樓層
Jason 發表於 2014-3-21 16:43
then it should be your computer setting problem.

please go through this:

Thx I'll look into it and see whether output color space makes a difference.

點評

good good!!  發表於 2014-3-21 17:04
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 樓主| 發表於 2014-5-12 18:03:32 | 顯示全部樓層
本帖最後由 vincecharus 於 2014-5-12 19:07 編輯

I tried and tried and tried and the problem persists.  

It is enough just to look at the watermarks.  The 1st one is cropped from the compressed pic on the thread, 2nd one is cropped from the uploaded 2MB pic.  Both are screen shots.

My thread is messed up: http://www.mclassic.com.hk/forum ... 6103&extra=page%3D1

All my pics are with sRGB output, so it's not a question of color space.

It kind of takes away from the joy of posting photos here. I'm sure some other c-hings here are upset about this, too.  They're just not as vocal as I am.

Please see if anything can be done about it.  If not, please at least advise on the optimal setting (size, resolution, etc.) for posting pics here.

Thanks!

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發表於 2014-5-12 18:59:30 | 顯示全部樓層
the left hand side is the compressed pic. the right hand side is the full size (2mb) pic i downloaded.

i don't see there is any significant difference.

other ppl, thought?

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 樓主| 發表於 2014-5-12 19:02:16 | 顯示全部樓層
本帖最後由 vincecharus 於 2014-5-12 19:07 編輯
Jason 發表於 2014-5-12 18:59
the left hand side is the compressed pic. the right hand side is the full size (2mb) pic i downloade ...

Upper one compressed, lower one 2MB, both screen shots on m-classic webpage.

These are my results.  If you click on the pics the differences are even more apparent.

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發表於 2014-5-12 19:10:52 | 顯示全部樓層
just to make sure we are on the same page.

what do you mean by the compressed picture? you mean the 800x533 pic shown directly on the pic? or the 2400 × 1597 pic after clicking on the image in the thread?
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 樓主| 發表於 2014-5-12 19:12:26 | 顯示全部樓層
本帖最後由 vincecharus 於 2014-5-12 19:13 編輯
Jason 發表於 2014-5-12 19:10
just to make sure we are on the same page.

what do you mean by the compressed picture? you mean the ...

800x533 pic shown directly on the pic = compressed

2400 × 1597 pic = 2MB file

(I know 2MB is also "compresssed" from DNG but that's not what I mean.)
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發表於 2014-5-12 19:14:37 | 顯示全部樓層
but the "compressed" pic you posted above (post #17) has an image size of 1606 × 1071. it should not be that large. it is stretching a 800x533 file to 1606x1071. surely there will be a problem.
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