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Discarding jpegs due to multiple edits?
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Apr 4, 2019 16:18:49   #
AndyH Loc: Massachusetts and New Hampshire
 
hassighedgehog wrote:
I always have the original JPG because I always use "SAVE AS" for my edited versions. No possibility of having to delete except for bad copies.


As long as you do all your edits in one session, that's lossless. It's only when you do a partial edit, and then want to edit the edited version after saving that you run into problems. In that case, you would have to save as TIFF, PNG, PSD, etc. Each time you open your original JPEG you are starting over. I understand the need that some have for JPEG originals, and I understand that some don't desire to do much post processing, but editing and JPEG just don't seem to go hand in hand to me.

Andy

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Apr 4, 2019 16:19:39   #
wdross Loc: Castle Rock, Colorado
 
burkphoto wrote:
For some professionals, JPEGs are an absolute necessity. We take precautions to ensure accurate exposure and white balance, and we take advantage of all the menu settings we’ve tested, with one goal: to maximize adjustment latitude by minimizing the NEED for it.

Then, minimal adjustment does little damage, and minimal compression leaves few or no visible artifacts.

Obviously, raw capture can provide far more adjustment latitude. What it can’t do is add value in situations where time to end use and labor costs must be minimized. There are MANY such situations.

I use both raw and JPEG capture. I have very well-defined use cases for each, and no snobbery regarding which is “better.” Both serve a purpose. Use the right tool for the job...
For some professionals, JPEGs are an absolute nece... (show quote)


"Use the right tool for the job..."
There are lots of people, UHHs and others, that really need to learn and understand this concept. It really cannot be stated enough times.

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Apr 4, 2019 17:50:17   #
imagemeister Loc: mid east Florida
 
BboH wrote:
When editing JPEGs do NOT edit and resave the original - make the edited image a "Save as..." (a new name) and then only edit that.


Yes, you CAN do this - just takes up more memory unless you delete the first ....I would consider doing this for something very critical - but I still do not worry or loose sleep ....

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Apr 4, 2019 17:50:51   #
pminyard Loc: Bartlett, Tennessee
 
I borrowed both the 1.4x and the 2x Canon extenders before making a purchase. I tried them on my Canon 100-400L zoom and comparisons between the photographs steered me to the Canon Extender EF 1.4X III. I am pleased with the purchase, even though I paid $429.00 for it.

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Apr 4, 2019 17:57:56   #
imagemeister Loc: mid east Florida
 
dsmeltz wrote:
Every time you save a jpeg you loose information even if you have not made any edits. Saving as a JPEG applies compression algorithms to the file. SO even if you have made no changes the save process will alter the file and re-compress the file resulting in degradation. If you edit a jpeg, save it to a new name. If you want to do something different, go back and edit the original and save the new edits under another new name. That way you are always starting with the same information.
Every time you b save /b a jpeg you loose inform... (show quote)


Yes, very simple if you are that concerned ....

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Apr 4, 2019 18:00:10   #
bwana Loc: Bergen, Alberta, Canada
 
pminyard wrote:
I borrowed both the 1.4x and the 2x Canon extenders before making a purchase. I tried them on my Canon 100-400L zoom and comparisons between the photographs steered me to the Canon Extender EF 1.4X III. I am pleased with the purchase, even though I paid $429.00 for it.

I think you responded to the wrong thread??

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Apr 4, 2019 18:07:49   #
Dean Sturgis
 
At risk of adding to this conversation I will add comments.
Years ago I took a jpg files from a negative scanned by a commercial processor of less than 3Mp, I opened it resaved it with out any changes I think 30 times. The last image did not look any different than the first, and after the 2 image the file size remained the same to the end. Some changes should not effect the image quality such as rotating by 90 degrees since the 4x4 blocks of the Bayer conversion of the pixel output remains unchanged.
But other changes I would think can destroy the image if resaved after every step. If you open the image & find it to dark go to Brightness & Contrast make the image brighter but with less contrast, save.

Open again correct the color and so on to make changes each step I will think the image will end up bad and probably smaller than the original file.
I lost where I put the pictures for the above files so I can't put them with this email

Dean Sturgis

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Apr 4, 2019 18:17:03   #
k2edm Loc: FN32AD
 
every time you SAVE a jpg it degrades [somewhat], BUT if you copy the jpg. screw with the copy and want to go back, fine, discard it and just go back to the original and copy another... i.e. copy means copy, only saving degrades it... in the digital world, ones copy as ones, zeros as zeros...only in the analog world do copys degrade..... Ed

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Apr 4, 2019 18:58:42   #
GrandmaG Loc: Flat Rock, MI
 
dsmeltz wrote:
Every time you save a jpeg you loose information even if you have not made any edits. Saving as a JPEG applies compression algorithms to the file. SO even if you have made no changes the save process will alter the file and re-compress the file resulting in degradation. If you edit a jpeg, save it to a new name. If you want to do something different, go back and edit the original and save the new edits under another new name. That way you are always starting with the same information.
Every time you b save /b a jpeg you loose inform... (show quote)


That sounds like a good plan!

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Apr 4, 2019 20:54:27   #
htbrown Loc: San Francisco Bay Area
 
This is why you should always save the original untouched, and only edit a copy. If you use LR or something similar, it doesn't actually change the file, so you're good.

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Apr 4, 2019 20:54:58   #
Traveller_Jeff
 
Blenheim Orange wrote:
Why intentionally degrade images to any degree?

Why edit JPEG files? Serious question.

Mike


I believe that LR does not do some things that PS can do. E.g., eliminate an element in a photo which I do with the clone stamp. (Perhaps some can do this in LR, not sure about that), Also, creating layers for photo-montageing elements not in the original image, photomerging (a very much used technique I make use of frequently), stacking several photos to create images in perfect focus; I'm sure other hoggers can offer additional uses for PS after completing stage 1 adjustments in LR.

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Apr 4, 2019 21:38:15   #
OleMe Loc: Montgomery Co., MD
 
1. As others have suggested, since there is progressive degradation, keep a copy of originals. That has saved my butt several times - and the copies are on a separate drive.

2. I use The GIMP to edit. The default save is in .xcf format, which as with PShop, saves the edits so one can go back. For the web, I scale-down / save the image as a jpg. It's not worth saving in a high-pixel-count format for the web as the resolution is "lost" on most monitors. Unless: the images are going into a photo album application that keeps the un-scaled image for download and initially displays the image(s) at a lower resolution.

3. As for the MAIN question, if one is not blowing up to poster size, modern digital cameras normally put so many bits into an image that, even tho jpgs are lossy, in my personal experience, it's rare that is reflected in the final, edited image.

/Roger

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Apr 4, 2019 21:57:53   #
AndyH Loc: Massachusetts and New Hampshire
 
Here's a test, so you can see for yourself. It's a simple JPEG, opened and lightly edited (Exposure, color, and clarity) three times using Windows photos, and saved over itself. The original is SOOC, the second image has been resaved three times. Download and compare. If the IQ is satisfactory for you, you don't need to worry about editing in JPEG format. If you don't like it, well, you now know how to avoid it.

Focus isn't perfect in the either one. Lossy elements are in the darker areas and the details, as in the grass. These are small images, so
you do need to zoom in to see the difference. In my judgement it would be visible, although not a complete deal killer, at about 8x10 or larger.

You be the judge. Remember, this is only the third generation. Under no circumstances do you want to go more than about double that.

Andy

Original version unedited
Original version unedited...
(Download)

3 saves
3 saves...
(Download)

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Apr 4, 2019 23:07:53   #
burkphoto Loc: High Point, NC
 
davyboy wrote:
Praise the Lord!👍


Puh-puh-puh-PASS thuh Loot!

(If you were in Charlotte, NC, in the early 1980s, you might get that inside joke about Jim and Tammy Faye Bakker’s ‘PTL Club.’)

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Apr 4, 2019 23:19:24   #
Blenheim Orange Loc: Michigan
 
Traveller_Jeff wrote:
I believe that LR does not do some things that PS can do. E.g., eliminate an element in a photo which I do with the clone stamp. (Perhaps some can do this in LR, not sure about that), Also, creating layers for photo-montageing elements not in the original image, photomerging (a very much used technique I make use of frequently), stacking several photos to create images in perfect focus; I'm sure other hoggers can offer additional uses for PS after completing stage 1 adjustments in LR.


Understood. I am not asking why a person would edit an image file, let alone suggesting that there is no reason to ever edit any image file. But why do edits (and by implication multiple saves) on JPEGs when it is so easy to work on a lossless copy of the image?

Folks have offered lots of alternative methods, any of which will prevent multiple save operations and potential degradation of image quality.

Mike

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