P: TIFF compression settings have no effect when Lightroom sends image to Photoshop for editing

It sounds like the Lightroom team made some changes (incompatible with their earlier wishes) that they failed to communicate to the Photoshop team. I'll have to check with them once I get back to the office.

Thanks very much, Chris - but then why is there an option in LR (Edit > Preferences > External Editing tab) that enables you to explicitly choose ZIP or LZW compression for files to be edited in PS?

It's this option that I've set to ZIP compression, but which seems to be ignored ...

Lightroom explicitly tells Photoshop to save the TIFF images with no compression when Lightroom opens the images in Photoshop for editing. Photoshop is just doing what the Lightroom team told it to do.

Suspected as much with your first para (though still prefer to have the 'render by LR' option), and completely agree with your second para - that's the problem.

Would be great to get a comment from the LR and/or PS teams to give their thoughts on this (when they're back from their holidays 😉 )

It is normal (and intended) that it is displayed as .NEF in PS. This is the normal way it should work when LR's and PS's ACRs are compatible: LR does not pass a pre-rendered TIF, but instead only passes a reference to the original raw to PS, plus the development settings. The ACR of PS is then responsible for rendering the image. When that is done, the original filename is disyplayed in PS (the image is now just in-memory, and is not yet a TIFF or PSD). Only when saving, PS uses the file type (PSD or TIFF) specified by LR to save the actual file (the image name displayed in PS changes accordingly).

What is still not normal is that the compression settings are ignored in the last step by PS (or perhaps they are not correctly passed by LR to PS).

This issue is still present with LR5.3 and ACR8.3 when opened in PS CS6. CTRL +S (Save) saves the TIFF file with NONE for compression. I would imagine it's the same with PS CC. Did you compare file sizes with CTRL S and then a 'Save As' with a different name selecting ZIP compression?

I think I can see what's happening. When I had incompatible versions of LR and ACR (LR5 and PS CS5 - no idea what ACR version that is but pre-LR5), the 'edit in PS' option in LR led to a box asking if I wanted to render with LR. Choosing this option exported a tiff to PS with the settings chosen in the LR preferences (e.g. ZIP compression), which came back into LR upon closing in PS. Perfect.

Now, I'm trialling PS CC with LR 5. The 'render with LR' option doesn't appear, and the file shows as .nef (not .tif!) in PS. When I subsequently save it, it's saved as a tif but with no options to choose compression settings. Significantly less than perfect.

Or am I missing something or doing something wrong?

My objective is to save all my tiffs with ZIP compression, without having to do a manual 'save as' which interrupts the round trip from LR --> PS --> LR.

that's odd, they come from the same company. they should be able to compatiable with each other. and tiff compression vb.net is an easy job for them too.

I checked the files using EXIFToolGUI and there isn't a significant difference in the metadata, so there's something else going on that remains a mystery.

I'm trying to provide you with some additional information. I don't know why the sizes differ, exactly. Also, the metadata may vary with your system setup and steps you've applied in editing the image.