Why is my image file coming out so large after using photoshop?

[JMR Photography]

Hello
I got a new mac laptop and everything has been upgraded, updated etc but noticed something unusual when I recently did some clean in photoshop. 

1. I have LR classic and had a couple of files - one was a jpeg 5MB and the other a raw file 24 MB

2. I clicked edit in photoshop with LR edits

3. The only thing I did non each of these images was a little bit of clean up with the clone tool - removed some spots on a wall, a light etc. Minor.

When I looked at the new psd file version both were around 88 - 90MB. 

Why is this so large? This was not happening on my older laptop/desktop. 

Running Mac OS Monterey 12.0.1

Thanks.

[dj_paige]

Conversion to TIF or PSD can cause this.  

https://feedback-readonly.photoshop.com/conversations/photoshop/photoshop-why-are-psds-so-much-large...

[JMR Photography]

But.... this never happened before when I select and image from LR and edit with LR changes. Those files were always coverted to psd and stayed close to the original size. Why would this be so massive with minor clean ups and how do you keep this from happening on future files?

[dj_paige]

But.... this never happened before when I select and image from LR and edit with LR changes. Those files were always coverted to psd and stayed close to the original size. Why would this be so massive with minor clean ups and how do you keep this from happening on future files?

By @JMR Photography

Then something else has changed. Maybe before you were working with JPGs sent from LrC to Ps.

But whatever was happening before, PSD files will be much much larger than the original RAW or JPG files, that was the case 10 years ago and it is still the case now. 

As far as keeping it from happening, I don't think you can 

[JMR Photography]

Thank you will try keeping the file as a jpeg when saving in PS. I do expect them to be larger but not that large! 

Have a good one. 

Julien

[dj_paige]

Thank you will try keeping the file as a jpeg when saving in PS. I do expect them to be larger but not that large! 

By @JMR Photography

Well, no, I wasn't recommending you use JPG at all. I was saying that was a possible reason for you not noticing this problem in the past. PSD files allow Photoshop to work with more information than an 8-bit JPG, resulting in higher quality results.

[Per Berntsen]

You may find these articles useful.

File formats

What is a digital image?

[Ranjisha Sengupta]

Hi there,

Thanks for reaching out; we're here to help.

How many layers do you have before saving the PSD.? Does this happen with images directly opened in Photoshop, or does only editing in Photoshop give these results?
As suggested, you can try and change PSD to TIFF or vice-versa and check the results.

Let us know how it goes,

Regards,

Ranjisha

[JMR Photography]

Hi

The computer is new and I think my tech may have mentioned that this was now in 64 bit which would make sense. Will check that. 

Thank you!

[Conrad C]

No, actually it wouldn’t make sense. I think I get what the tech is saying…if you upgraded from a much older Mac running a 32-bit version of macOS and Photoshop, and you got a new Mac (all of them now run 64-bit macOS and applications). Some system files may be larger because of that difference between 32-bit and 64-bit macOS. But that does not change the file sizes of any user documents, including any photo documents. When talking about any computer OS, 32-bit vs 64-bit refers to how many bits are used for processing, not how many bits are stored in user files.

The proof? If you open one of your “too large” Photoshop files and choose Image > Mode, the submenu will probably show that the document is 8 bits per channel or 16 bpc. It will definitely not say it is 64bpc, because that basically isn’t done today.

[JMR Photography]

Hmmmm. that still leaves me to wonder how a 5MB file goes to 88MB with only one layer. Yikes

[Conrad C]

If you read my longer reply, it explains that:

It isn’t that a 5MB JPEG shockingly expanded to an 88MB Photoshop file, it’s that the 5MB JPEG is so unnaturally small.

The Photoshop file size is closer to the natural file size of an image, and the JPEG is so small because so much of the original quality has been thrown out of it. But when opened in any pixel-based image editor (not just Photoshop), a JPEG file must be expanded to the natural image file size for it to be editable.

[JMR Photography]

Forgot to mention - one layer only. 

[Conrad C]

It may be counterintuitive, but this is normal, and it should have always been happening on any computer with any application. The file size will change even if no edits are made, because the change is about the nature of each format you are moving it through.

The short answer is that both JPEG and raw are not the “normal” size of any image. JPEG is highly compressed, and raw requires development before it can be used. Those compromises allow the file sizes to be much smaller than normal. We get used to these small file sizes, so we think they get too large when converted to Photoshop or TIFF format. But the truth is that the file size of Photoshop or TIFF format is the real file size for a fully editable, full quality RGB image.

The natural file size of any image is:

Number of bits * number of bits per pixel * number of pixels

Suppose you have a 24 megapixel file (6000 x 4000 pixels).

If you run it through that formula, you get from roughly 70 to 140MB depending on what bit depth you chose and what file options were set. That’s the natural file size of that image, and that’s why it’s the size range you get if you save in Photoshop or TIFF format.

The JPEG file is much smaller because a lot of the original quality has been squeezed out of it, but if you convert it from JPEG to Photoshop format and save, it must be expanded to a full uncompressed document for normal editing. That is what causes the file size increase from JPEG to Photoshop.

The raw file is much smaller for several reasons: It doesn’t have three RGB channels (yet), it’s one channel of raw data. And some cameras compress the raw file, although not as much as JPEG to preserve more quality. But you can’t edit or print that raw file until it’s expanded to three RGB channels. A raw editor such as Lightroom Classic does that expansion behind the scenes as you edit so you don’t see the file size increase there (until you export to Photoshop or TIFF), but Photoshop converts it to three channels up front before editing, which is a big reason behind the file size gain there.

One thing that could be happening with raw files: If Adobe Camera Raw on the old computer was set to convert to Photoshop at 8 bits per channel, but on the new computer is set to convert at 16bpc, the converted file size on the new computer could be twice as large.

[richardplondon]

One thing that could be happening with raw files: If Adobe Camera Raw on the old computer was set to convert to Photoshop at 8 bits per channel, but on the new computer is set to convert at 16bpc, the converted file size on the new computer could be twice as large.

The same may happen for the external editing options that are set inside Lightroom Classic. These govern how Photoshop is going to receive images for editing, and also set the defaults for how those will be saved to disk.