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filtered jpgs
#59210 07/24/21 12:50 PM
Joined: Aug 2009
Likes: 1
jaybass Offline OP
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Joined: Aug 2009
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OS 10.14.6

Is a filtered jpg better than a jpg? After reducing noise using noise ninja, the size of the image in MB is reduced. Expanding the image before and after, I see no difference.

I submit images to dreamtime both filtered and unfiltered and if refused, they have never mentioned this point.

Thoughts anyone?

jaybass


OS 10.14.6 iMac (Retina 5K, 27", 2017, 3.4 GHz Intel Core i5, 24 GB RAM, 2400 MHz DDR4. SuperDuper. 1 TB Lacie HD, Noise Ninja.
Re: filtered jpgs
jaybass #59211 07/24/21 01:13 PM
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By its very nature JPEG compression is a lossy process. According to the site resizer.app: "The quality of a JPEG image decreases as its file size decreases, and constantly editing and re-saving JPEG photos may further cause the quality to degrade."

To me, the real question is whether I or the person using the JPEG will notice the loss of quality. If it is noticeable, using the RAW format of the image for editing is recommended.


On a Mac since 1984.
Currently: 27" iMacs, Macbook Air, macOS 10.15.x,; iPhones, iPods and iPads galore!
Re: filtered jpgs
jaybass #59212 07/24/21 03:18 PM
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You will find a highly technical scientific comparison between jpeg and filtered jpeg in this International Journal of Computer Operations article. If you are not interested in the mathematics and comparison tables in the article, the conclusion is:
Originally Posted by International Journal of Computer Operations
However, all the decoded images resulting from this approach and original images are almost the same in human perception point of view.
In other words you are not the only one that can tell little, if any, difference in jpegs and filtered jpegs other than a reduction in the file size. There are other factors that can and will have a highly noticeable effect on jpeg image quality.

If image quality were important, JPEG would be at or near the bottom of my list of choices.



"Sacred cows make the best hamburger"

- Mark Twain
Re: filtered jpgs
Ira L #59213 07/24/21 03:28 PM
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jaybass Offline OP
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Ira,

I always edit the RAW image but as you probably know, dreamtime want the submission as a jpg. I always enlarge the image a minimum of 3 x to see if it's a keeper.

I have been using Noise ninja after converting to a jpg but I can reduce noise in affinity photo and then export as a jpg. Better.

Thanks Ira,

jaybass


OS 10.14.6 iMac (Retina 5K, 27", 2017, 3.4 GHz Intel Core i5, 24 GB RAM, 2400 MHz DDR4. SuperDuper. 1 TB Lacie HD, Noise Ninja.

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