Using PhotoLab 4 with 1.8 GB Images

Before embarking on a project to have 4x5 negatives drum scanned with resulting images up to 1.8 GB in size, I’m wondering if my system and PhotoLab 4 can handle the resulting files for post-processing.

I have a 2013 Mac Pro, 6-core Xenon E5 with 64GB RAM and dual 3GB graphics cards running macOS 11.0.1 (Big Sur) and the latest version of PhotoLab 4.

Does anyone have any idea what to expect when opening and processing my first very large image?


One question - why do want such large files? What size are you planning on printing to?

I scan at 2400ppi and that allows me to print up to 50" x 40" at 240ppi.

I do have some B&W TIFFs that are about 1.8GB, but that’s with 3 curve layers, and they load into PL fine, in a couple of seconds.

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That seems like impressive performance.


I just did a timing test. With PL4 closed, I opened the TIFF file from en external drive with PL4 and it took 11 seconds before the image was showing. That’s on a MBP 16" 16GB memory 1TB disk.

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OK. weird stuff can happen with TIFF files that include adjustment layers.

It might load fast but PL4 really doesn’t like that image. Here’s a screenshot of the tone curve palette

Capture d’écran 2020-11-23 à 21.16.59

As you can see the upper limits are no longer 255 but 6502!!! What’s more, what you can do with the curve is very limited and you can’t reset it.

I tried loading a TIFF without any additional layers and it works fine.

@StevenL I think I have just discovered a bijou buguette :nerd_face: That is, unless PL was never meant to handle such files?

One question - why do want such large files?

It is not necessarily what I want. It is simply that the guy I trust the most to do scans does drum scans and that is the output resolution. I do have another source lined up to do flatbed scans that I certainly want to try, but would still want a couple of drum scans of special images to compare. It is good to know that hardware and software should not be a problem.

But since you mentioned having some of the 1.8GB files, have you compared them to something like 80-100 MB flatbed scans? Can you tell any difference at all when viewed on a large monitor or a 50x40 print, or see any difference in post-processing?

And finally, if you do have your own scans, what scanner do you have, and are you happy with it? At this point, I want to see some professional scans, but financially that probably isn’t the best long-term strategy.

Sorry for all the questions. Just trying to wrap my head around all the options.


I don’t know too much about individual drum scanners but I would have thought he could scan at lower resolutions - unless you really want to print at humungous sizes.

I have never had drum scans done, being satisfied with the results I get from an Epson V700 with a BetterScanning film holder. If I want to, I can scan up to 2400ppi to give me 50" x 40" prints but, normally, I’m only interested in 25" x 20" prints at the most, so scanning at 1200ppi is fine and considerably reduces the file size.

Yeah, PL is not really meant to read multi-layered TIFF files which contains adjustment layers…

And why not? :crazy_face: :roll_eyes: :hugs:

Nonetheless, it seems perfectly happy to read and display the image, and most adjustments I have tried seem to be fine, it’s just the tone curve that’s a bit “off”.

Hopefully @Ajoe’s scans will not have adjustment layers and from my experience so far, PL seems perfectly happy with single layer larger TIFF files.

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For the record, if you do come across a multi-layer TIFF file and you want to edit it in PL, all you need to do is open it in macOS Preview and then export it to TIFF under a different name/directory. Then you will have a single layer file and PL will be quite happy.

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Hi Joe,
I stack and stich (panorama stitching) and have taken PL to its limits regarding file size. So long as your TIFFs do not exceed 2GB then PL should read it no problem. Generally working at this size is fine no problems that said some tools such as local adjustments will be a little laggy which is understandable.
Let us know how it goes!

Just messing around further with some of my large TIFF files.

I used macOS Finder to simply duplicate a file to play around with - it was one of the multi-layer files that was causing weird numbers in the tone curve.

Believe it or not, just by duplicating it, the tone curve on the duplicated file now displays 255 as the maximum value and yet, if I go back and open the duplicated file in Affinity Photo, all the layers are still there.

So it looks like there was something whacky in the original file that, somehow, got fixed simply by duplicating it :crazy_face:


Finally found it. The duplicate didn’t yet have a dop file. When I deleted the dop file for the original, the tone curve numbers turned out normal. Seems like it may well have been simply a corrupted dop file.

@StevenL, it might need further verification but it seems that PL can deal with multi-layer TIFF files after all :nerd_face:

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Awesome :v: