Fact or Myth: JPEG deteriorates over time


Fact or Myth JPEG deteriorates over time

I have read quite a few things whilst researching articles, and some of those things I have to say I have found alarming. This is a question that people ask which I want to give reassurance

JPEG files do not deteriorate over time. This is a myth. If you open and close a JPEG file a million times this does not degrade the image at all. So do not worry – your precious JPEG files are just fine and not deteriorating quietly in the background. However, every time you edit and save a JPEG you will lose some image quality though, and this is irreversible. So take photos in RAW if you can and save in JPEG and the problems all go away.

But don’t worry – I will tell you all about this and what you should and should not do to protect your images, including a super smart way of getting rid the problem of quality loss forever and a day. YesI have the answer to this problem!!

Who am I to tell you about this stuff?

I am Rick McEvoy, a professionally qualified architectural and construction photographer based in the UK. I have been learning photography for well over 30 years, and on my blog I create content to help people understand the things they need to understand to help them with their photography.

And in doing this I have learned loads myself which has helped me with my photography so all is  good  – we are all in this together!

Photography Explained Podcast

In 2020 I launched the Photography Explained podcast, where I explain photography things in plain English in less than 10 minutes without the irrelevant detail. Yes that is my tagline, which I really need to work on.

Sorry but I would like to bring this to your attention before I go on.

Here is a direct link to my podcast feed.

OK – lets sort this JPEG thing out

What is JPEG?

JPEG is a file format. PDF is a file format, just for other things. So JPEG is just one of the file formats that is used when a digital photo is created.

What does JPEG stand for?

JPEG is the Joint Photographic Experts Group. And that really is not important in the context of the question in this blog post. Sure you can find out more about this group, but I for one will not be doing that, as it will not help me with my photography.

But I do have to say that we should all be grateful that this group came up with a universal file format.

Why are there different file formats?

That is a great question. There are different file formats for different needs and uses. The two main file formats in digital photography are JPEG and RAW. There are lots of others, and to answer the question of this post I need to refer to the RAW file format.

So do JPEG files deteriorate over time?

No. They do not. But there are other ways that JEPG files deteriorate, or lose quality, which I will explain here now that the fundamental question has been answered. And I will add here – don’t worry – it is good to know these things and be aware of them but don’t worry – ok?

How do JPEG files lose quality?

JPEG files lose quality when an image is saved to the memory card every time you take a photo.

What I hear you say?

Yes, every time a photo is taken there is a loss of quality that is caused by the processing of the image. This is in comparison to RAW files where there is (virtually) no processing of the image, and (virtually) no loss of image quality.

And each time you edit and save a JPEG file there is also a loss of quality.

And every time you compress a JPEG image you lose quality.

What about RAW files?

RAW files do not have any processing applied to them when an image is taken, unlike a JEPG file. Well other than taking light and converting it into a digital image that is.

If I edit a JPEG files once do I lose image quality?

Yes. A little bit.

If I edit a JPEG files more than once do I lose more image quality?

Yes – each and every time you edit and save a JPEG image you lose some quality.

And this is the point. Edit an image once and you lose some quality. And if you do not edit the image again you do not lose any more quality. Your file will remain as it is, sat there happily not losing quality over time!

So JPEG files do not deteriorate over time. Just so we are clear!

What is file compression?

Well JPEG processing is a lossy process. That means that each time an image is created or processed (i.e. saved) there is an inevitable loss of image quality in the processing of the image.

When you save an image you can choose the amount of compression. And when you save a RAW file as a JEPG you can also choose the amount of compression – see what I do further on in this post for more on this.

Are there different types of JPEG quality?

Yes there are. On my Canon 6D there are two JEPG settings, fine and normal. Fine is a higher quality than normal.

How to eliminate the problem completely forever

This is what I do.

  • I shoot in RAW.
  • I edit in RAW in Lightroom
  • I export images out of Lightroom in JPEG.
  • A new file is created leaving the RAW file.
  • I choose the appropriate compression for the image use.

If it is for email I use the Lightroom email export preset. A new smaller JPEG file is created leaving the original RAW file where it was.

If it is an edited image for client issue I use 92% compression. A new smaller (but bigger than the email example above) JPEG file is created leaving the original RAW file where it was.

Why 92% compression?

Well this is a magic number from years ago – does it still apply? I still use it. I cannot tell the difference between an image exported at 100% to an image exported at 92%, other then the latter file is much, much smaller.

RAW and JPEG

I don’t shoot in RAW and JPEG – this is just doubling up on the work.

Do I worry about this?

No I do not. Then again it is easy for me to say as I have been using Lightroom for years and know what I am doing with RAW files.

The reality of all of this.

If you can shoot in RAW and export in JPEG the problem goes away. If you are not able to shoot in RAW just edit an image once and be careful with your compression settings and you should not have a problem.

This issue of loss of quality can be managed by learning how to process and compress JPEG files correctly.

And if you need to re-edit an image then you will lose some image quality – just check before you do something with an image like share it.

We talk about lossy processing and loss of quality but the reality is you might not be able to even see it.

How this might be a problem

Edit an image loads of times, or compress the file loads of times and you will have problems – visible loss of image quality.

And then make en A3 print and you will probably get a rubbish print back.

How do you know if there is a loss of image quality?

Zoom into 100%. Compare the image that you have processed and saved or compressed and compare with an image that you have not processed or compressed and just look – spot the difference!

Summary

Don’t worry about this too much. Be aware but don’t worry.

Once you have edited a photo then call it good. Take time over the original edit and you will hopefully not need to come back to it.

Spend more time taking photos than editing them. And learn how to edit photos properly.

Shoot in RAW if you can.

But remember that JPEG files do not deteriorate over time!

And that is my final word on this.

Thanks for reading this blog post which I hope you found helpful, informative and reassuring.

Rick McEvoy MCIOB, ABIPP

Rick McEvoy

I am Rick McEvoy, a professionally qualified architectural photographer living and working in Dorset and surrounding areas. I create high quality architectural photography of the built environment for architects and commercial clients. I do not photograph weddings, families, small people or pets. For more info about me check out my about page here https://rickmcevoyphotography.com/about Rick McEvoy ABIPP, MCIOB

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