Save JPEG at original quality

[bpedit]

I have massive numbers of digitized slides to process. I'd like to open each, make a few adjustments, then save as a JPEG. But when I do the file size bloats tremendously from, say, 1.3 Mb to 6 Mb. I suspect this is due to saving at 100% quality. If I export the file instead at, say, 95% quality I get a reasonable file size. But what a hassle invoking Export, changing the quality (I think it then remembers this) then entering a file name and saving. 

Is there any way to set the default quality as applied to simply using the Save button on an open JPEG? 

[walt.farrell]

That's not easy to do, and in general not really possible, as the Quality setting is not saved in the JPG file.

There are applications that will try to infer the quality setting when saving, but the Affinity applications don't do that.

[NotMyFault]

31 minutes ago, bpedit said:

I have massive numbers of digitized slides to process. I'd like to open each, make a few adjustments, then save as a JPEG. But when I do the file size bloats tremendously from, say, 1.3 Mb to 6 Mb. I suspect this is due to saving at 100% quality. If I export the file instead at, say, 95% quality I get a reasonable file size. But what a hassle invoking Export, changing the quality (I think it then remembers this) then entering a file name and saving. 

Is there any way to set the default quality as applied to simply using the Save button on an open JPEG? 

When opening the Export menu, you can choose export format (JPG) and within that format, a preset. To create an own preset, click on the little burger menu. You need to adjust any settings like Quality to a different value before you can save a new preset. In my experiments, Affinity remembers the last used preset.

 

[bpedit]

Thanks. I was aware of that feature in Export, you're correct that it seems to remember the setting (until closed anyway). My question was directed at trying to avoid the Export menu and just saving directly. But on further investigation it appears  that, at least,  the name is preserved as the default save name in Export. So this means three extra button pushes and two extra mouse moves per image compared to a simple save. Times 3,600 images!

Walt: I understand there's no inherent metadata of the saved quality, I was hoping for a way to set a default quality applicable to the Save function. Poor titling on my part, sorry.

[NotMyFault]

1 minute ago, bpedit said:

Thanks. I was aware of that feature in Export, you're correct that it seems to remember the setting (until closed anyway). My question was directed at trying to avoid the Export menu and just saving directly. But on further investigation it appears  that, at least,  the name is preserved as the default save name in Export. So this means three extra button pushes and two extra mouse moves per image compared to a simple save. Times 3,600 images!

Walt: I understand there's no inherent metadata of the saved quality, I was hoping for a way to set a default quality applicable to the Save function. Poor titling on my part, sorry.

To save some mouse moves and clicks, there are two alternatives:

• use keyboard shortcuts (one for Export, plus enter)
• use macros and/or batch processing. If you have the task to edit 3600 images: are these edits same/similar to many images, or specific to every single image?

To be honest, Affinity apps currently do not shine for mass-edits. Other tool might be better suited. Never the less, in certain cases you can simplify or improve the workflow or automate it partially or fully even with Affinity apps. Can you give some more insights about what edit steps you are planning?

[NotMyFault]

Another aspect to consider: 

Affinity apps tend to corrupt files occasionally in many ways. I would recommend to never save directly over a source file.

My best practice is to always save in new files, inspect the results, and delete source file only after checks. If you spot an issue, at least you have the chance to try again.

[bpedit]

The edits will very depending on the image. Dust removal, white point adjustment, contrast, dozens more possibilities unique to each photo. Color correction for wash-outs from the 1960's. While I understand the philosophy of keeping the "original" archived, with 3600 photos I won't be saving to new files and doing the comparisons you suggest. These are scanned to begin with, some uneditable editing was done then. This is a 'get it done' operation, its why I was looking to save 10,000 keystrokes and 7,000 mouse moves.

I guess my original question should have been a simple "can you adjust the JPEG quality as applied to the save button when a flattened JPEG is active". The answer appears to be no.

[NotMyFault]

Thanks for clarifying. Nothing to add from my side.

[carl123]

9 hours ago, bpedit said:

I guess my original question should have been a simple "can you adjust the JPEG quality as applied to the save button when a flattened JPEG is active". The answer appears to be no.

The answer is no but what you could do is process all the JPGs using the Save button, then, when done, run a batch job (File > New Batch Job) to reprocess those JPGs with the compression (quality) value you want, overwriting the original JPGs

[walt.farrell]

6 hours ago, carl123 said:

The answer is no but what you could do is process all the JPGs using the Save button, then, when done, run a batch job (File > New Batch Job) to reprocess those JPGs with the compression (quality) value you want, overwriting the original JPGs

I like that idea, except that every Save operation loses information when saving JPG files. Even with a 100% Quality setting there is lossy compression involved while Saving. Perhaps, for most photos, one extra Save operation won't be noticeable when looking at the images later, but it's not an optimal workflow in my opinion.

(On the other hand, it may be acceptable for a user who's not using 100% Quality anyway.)

[bpedit]

16 hours ago, carl123 said:

The answer is no but what you could do is process all the JPGs using the Save button, then, when done, run a batch job (File > New Batch Job) to reprocess those JPGs with the compression (quality) value you want, overwriting the original JPGs

Interesting. Would this be the same, quality wise, as saving from the original opened file at the new resolution? I may test this.

Walt: I can't tell the difference between saving at 100% and saving at 95%, even at magnification. I would challenge others to point out the difference. Remember, I'm not working with high resolution digital originals but images of 35 mm slides taken with a 12 Mp scanner. The memory savings for my collection would be on the order of 25 GB.

[NotMyFault]

The point is that repeated saving of the same unedited file with jpeg compression can degrade quality dramatically. The basic advice is to not use JPG as intermediate format, (or any other format with lossy compression) when you want to edit the file later. The compression eliminates all the "headroom" required for editing, and causes artefacts.

JPEG is ok to store the final version using 85% quality (in Photo) for export.

Even with 3600 images, you should not bother about file size, a current 1TB SSD cost about 100 bucks.

https://fstoppers.com/education/about-jpeg-images-and-their-quality-degradation-435235

 

If you intend to produce images for social networks where dramatic over saturation, fake HDR and sub-second attention period predominates, quality it does not matter. If you intend to produce images for e.g. books, printouts, or e-Books with focus on image, those details matter. A question of personal preferences.

[bpedit]

6 hours ago, NotMyFault said:

The basic advice is to not use JPG as intermediate format, (or any other format with lossy compression) when you want to edit the file later.

The scanner offers no choice but JPEG. 

[carl123]

The quality loss argument when saving a JPG file with compression is severely overhyped and best left in the pro-photography world

Overwriting a 100% JPG file once, twice or even three times is unlikely to display any noticeable difference to the average human

I frequently download JPGs from the internet, work on them and export them with compression (85% quality) then later on I may have to tweak that exported JPG and export it again and I see no visible degradation in the image when doing this.

Don't believe the hype for general JPG usage - unless you are a professional photographer and need/want to squeeze every ounce of quality from an image that you can

 

7 hours ago, bpedit said:

Interesting. Would this be the same, quality wise, as saving from the original opened file at the new resolution?

Technically no.

If you open the JPG and export at 85% quality that is what you get

If you open and save the JPG it uses "100%" quality. Which in reality, due to the lossy nature of JPG files, is probably 99% or 98%

So, if you now export that file at 85% (via the batch job) you're probably looking at an overall quality of 84-83% of the original JPG file

But it's so small a drop versus just exporting the file (at 85%) it's hardly worth worrying about for the benefits of being able to batch process your files rather than doing an export for each one.

 

 

[laurent32]

Hope you won't mind, i'm a little curious @bpedit, did you use one of those scanner :

 

If so, how is the quality of the scans ? and does it work fast ?

Thanks for your feedback.

[bpedit]

9 hours ago, laurent32 said:

Hope you won't mind, i'm a little curious @bpedit, did you use one of those scanner :

If so, how is the quality of the scans ? and does it work fast ?

I used a Kodak scanner, a SLIDE N SCAN, it reviewed a bit better than the Kodak you pictured.

It's fast at snapping the pic, the time is mostly in giving the slides a blast of air and feeding them into the scanner. The quality was mostly pretty good, some batches ("trips") not as good but that appeared, after examination with a scope, mostly a matter of the quality of the original. If you just have a few to do a professional job would probably be better, they pay more attention to cleaning and have better scanners, too expensive for a one-off use. This was adequate for my use. Remember to keep an eye out for specks lodging on the platen and use the included brush to remove them.

[laurent32]

I think I'm going to buy one…

In the attic, I guess I have more than 300 rolls to deal with…

So many memories…

[debraspicher]

You could set the Export dialog shortcut to one of your F-keys (except F1) since those are usually left open for user-assignments. It will make it at least a bit more accessible.. and then hit Enter.