Photoshop does not allow to save as JPEG 2000

[Alfred5E88]

I have created a large panorama stich (45K pixel wide) which I would like to save as JPEG 2000.

But Photoshop only allows the following formats: JPEG, PSB, JPS, MPO, RAW, PNG, TIFF, WEBP.

Not JPEG 2000 - why?

[davescm]

It would appear Photoshop's implementation of JPEG2000 saving uses a maximum width of 30,000 pixels (the same as PSD).

That is the what but, not being an Adobe developer or employee, I can't answer the why.

Dave

[Trevor.Dennis]

Can you tell us why you need such a large document, and save in that particular format?

[Alfred5E88]

When you stich a large enough number of images, you can get pretty large image files (up to  the gigapixel range).

The idea was that perhaps JPEG 2000 could store such a file in less space (i.e. more compression, but same image quality).

But why on earth wouldn't Adobe fully support JPEG 2000?

[D Fosse]

Yes, but the thing is, you don't need it for any real-world purpose, unless you work for NASA.

As for the JPEG 2000 format, it doesn't seem to be used much. You are the first person I can remember here asking for it. Not that the jpeg specification didn't need improvements, but now we have better alternatives that are actually used, like HEIC, AVI and WEBP. Proper Photoshop support for those seems more urgent. The JPEG 2000 initiative seemed to just sink without a trace.

[Alfred5E88]

I captured a scene of a far away place (1 day of travelling including a 12 hours flight to get there) at highest possible resolution, because if I need more pixels of something later, it's not an option to get back to that place and capture a new image.

In any case, there is a need to store large image files in a compressed format. If not JPEG 2000, what should I use?

[Alfred5E88]

Ok... Irfanview is able to convert the TIF file to JPEG 2000, but then Photoshop can't read it.

Then I saw that something called "JPEG XL" exists. Irfanview can convert the TIF image to JPEG XL and Photoshop can at least open the JPEG XL file created by Irfanview.

But perhaps this JPEG XL is even more "exotic" than JPEG 2000? So what format should we use to save very large images in a compressed format?

[Stephen_A_Marsh]

So what format should we use to save very large images in a compressed format?

By @Alfred5E88

When I created a 45K square RGB 8 BPC flattened file, good old JPEG was still offered as a standard Save A Copy format.

[Alfred5E88]

Ok, but what to use when the image has more than the JPEG limit of 65K?

[Trevor.Dennis]

OK, you need the max res files as a fall back, but that's not to say that that's your only option for merging them.  You could batch resize them with Image Processor, and plan for a more manageable resolution and file size. 10K pixels on the long side would make a decent sized print, for instance.

You mentioned gigapixel.  Did you mean that strictly in terms of file size, or the extreme zoom capable images like on Jeffry Martin's site, or the more famous Bert Monroy Times Square illustration?  (I actually can't find a link to the gigapixel Times Square image.  You can see the making of it here  If anyone knows where to find the zoomable image, that would be cool).

[Alfred5E88]

"Gigapixel" simply means an image with more than one billion pixel, i.e. 1000000000 pixel.

With today's high resolution cameras it's not too difficult to stitch together an image in that range.

For this 45K image I used a modest 20MP camera and merged 16 images. If somebody uses a more sophisticated camera with 40, 50 or 100MP, it's easy to create a panorama image which exceeds 30K or 65K pixels in a dimension.

So, Photoshop should support a format capable of storing such image files in a compressed way. Right now to my knowledge it only offers JPEG and that is available until 65K. I was thinking that JPEG 2000 would be better, but I also noticed that there is a lack of support of JPEG 2000 in most image browsers. JPEG XL exists on paper, but seems to be even less supported.

[davescm]

Have tried simply turning on compression for PSB files to use as 'master' files. It uses lossless compression and supports all the functionality of Photoshop such as layers, alphas, higher bit depths etc . Personally I turn compression off as I prefer faster saves and opening times, to smaller files (disk space is relatively cheap these days) but it does have its place.

Dave

[D Fosse]

Indeed. If you're going to have these pixel sizes - for whatever reason - then obviously file size isn't an applicable parameter at all. This is going to be huge simply by being what it is, and you just need to make room for it.

In other words, PSB is the only format that makes any sense to use here. 

If you turn on compression, it will take an extremely long time to open and save.  I'd save this uncompressed.

[Alfred5E88]

Well, this 45K wide image (the JPEG of it) opens in 2 seconds in Photoshop on this PC. Fast enough in my opinion.

PSB is not supported by the ACDSee image browser I'm using (i.e. I can't open this 45K PSB image file with ACDSee).

Photoshop (I'm using version 25.6.0) doesn't offer the option to save PSB compressed (only uncompressed, which results in too big file sizes).

[davescm]

Psb and psd file compression is set by the same checkbox in Preferences - File handling.

Standard jpeg is lossy - so the image deteriorates every time it is re-saved.

Dave

[NB, colourmanagement net]

@Alfred5E88 

A few notes on Jpeg:

Jpeg files have compression applied, changing resolution or cropping and re-saving enhances the compression artefacts - this means that Jpeg is only really suitable for final file delivery/transfer - with the Jpeg created only once size and resolution (and any sharpening) have been completed. 

So,Jpeg is a far from ideal for editing and not OK for archiving or for any file that may need to be resaved, resized or cropped down the line.

Jpeg is the worst possible format if you want to keep high quality - you should always archive a copy of your original, ideally with any adjustment layers intact - if you work with layers.

Jpeg compression (at any setting*) really is "lossy”, irreversible and cumulative, so Jpegs should ONLY be used only for final delivery and only created from the original file format AFTER resizing & cropping to the FINAL size and crop.

To explain: any edits to size or crop, or even just re-saving a Jpeg file means further compression, potentially that’s very damaging.

The JPEG compression damage is not always immediately apparent, which is perhaps why it's still widely used - however, that compression will soon cause issues if you do further work and save again. That’s when you’ll see a Jpeg with some real issues.

*don’t imagine that selecting maximum quality for your Jpeg is preserving the original data, it’s still compressing a lot which discards information.

SO, don’t reuse Jpegs if any resizing or resaving is needed. Always go back to the PSD/ Tiff originals, Jpegs are essentially a 'use once and trash' file type.

I hope this helps
neil barstow, colourmanagement net - adobe forum volunteer - co-author: 'getting colour right'
google me "neil barstow colourmanagement" for lots of free articles on colour management

[Alfred5E88]

Right, and JPEG is limited to 65K x 65K pixel. So, which compressed format would one use for very large images?

[Lumigraphics]

Adobe is apparently phasing in JPEG XL (which is different thatn JFIF/JPEG and JPEG 2000) as an internal file compression method (DNG Converter can use it currently.) I'd probably use PSD/PSB or TIFF with ZIP compression if possible.

[D Fosse]

PSB.

You're deliberately creating these huge images, which I still maintain is massive overkill for any practical real-world purposes, so you just have to accept that the file size is also going to be huge. You can't buy a car and worry if it will fit in your shoe rack. So to speak.

[frazzlesnap]

@NB, colourmanagement net 

That's a very concise and helpful assessment of the jpeg format. I always save originals as tif/psd/psb, and use jpegs as proofs. I've spent so many hours over the past 27 years explaining compression artifacts and the problems of re-saving jpegs to customers that I think it amounts to a few months of work.

Anyone who needs an extremely large image without degradation should use psb, and never use compression, unless it is truly lossless.

Thank you for posting that.