New iMac very slow to render large TIFF files

dialabrain wrote:

Just curious where people are finding 500MB TIFF files?

I'm using satellite imagery. A 500 MB image is medium size. I used band 8 from one of my Landsat 8 test scenes, which is 473 MB. Here are various ways to download: https://landsat.gsfc.nasa.gov/data/data-access/

vasileios225 wrote:

The problem of slow rendering ( TIFF PHOTO FILE 500MB) appears to apply ONLY TO PREVIEW! My photo Apps AFFINITY PHOTO, DxO PHOTOLAB 6, TOPAZ GIGAPIXEL AI, they ALL, open and render instantaneously, same file on disk or external drive! PREVIEW takes 2 1/2 minutes to fully render! Any thoughts on that? Hardware ( I doubt it) or Software?

The physical size on disk of any modern image format isn't very significant due to compression. This can be a problem for JPEG files which are very highly compressed. The problem is that the physical dimensions of the image may be very large.

Most professional apps are prepared for the possibility of such enormous images and will load the image in chunks. Preview is relatively simplistic. It will simply try to load the entire image at once, causing high levels of swap usage. On top of that, it may still try to divide the image into chunks because the video buffer isn't large enough. So if you are only seeing the problem in Preview, that is the most likely cause.

A contributing factor is likely the differences in operating system versions. Apple tends to rewrite the Preview app every year. And every year, they get it wrong. I've already confirmed that Preview doesn't even handle colorspaces properly. That's really bad. So it wouldn't surprise me if there are other parts broken too.

Most TIFF files don't have very high levels of compression, so this usually isn't a big problem. However, there really isn't any true "TIFF" format. It's more of a specification. There are ways to construct TIFF files with extremely high levels of compression. In fact, you can construct TIFF files using JPEG compression. I've even seen TIFF files with WebP compression. Those images are unbelievably slow to render.

You have a lot of junk apps installed guaranteed to slow down disk access. The Mac OS does not, in any way, need help with its own file system. Add-on software included with third party drives only succeed in adding complexity to data access. Which means everything is slower, and greatly increases the possibility of corrupt data.

Remove anything to do with:

Western Digital (WD)

Samsung

Never install any of the junk that comes with third party drives. Ever.

Do you actually have a RAID set up? If not, remove the LaCie junk.

Do you really need software like Citrix? As a general rule on Macs, any and all AV / security software is a waste of money and system resources. I would strongly suggest you remove it.

Remove Chrome and its launch daemons. I really don't get what people think is so great about Chrome. It's a known, massive resource hog. On top of that, from the moment you turn your Mac on to the time you turn it off, it is constantly sending anonymized data of your computer and web usage to Google's servers. Chrome doesn't even have to be running. The keystone agents…

/Library/LaunchDaemons/google.keystone.agent.plist

/Library/LaunchDaemons/google.keystone.xpcservice.plist

…do that by launching apps buried within the Chrome app, which load at startup. And then there's this.

We don't allow any software written by Google on our Macs. Not Chrome, Google Earth, or anything else. Google's real business is collecting marketing data. You are their unwilling and unpaid source for it when you use any of their junk. If Safari isn't a browser you care much for, try Firefox or Brave. If you have one, you do not need Chrome to access your Google/Gmail account. You can do that from any browser.

Brave in particular is an excellent replacement for Chrome. It’s built on the same open-source Chromium web code, but without any of Google Chrome’s intrusive data harvesting. What makes it a better alternative are dumb web sites (like some banks) which insist you use Chrome for access. In almost all cases, Brave also works.

And yet another reason to never allow any app written by Google on your computer.

Google told users that when using incognito/private mode, Chrome would not track your usage, or collect data. They lied. It did anyway. Google has now agreed to settle the 2020 lawsuit with a five billion dollar fine.

But even so, according to another article on the lawsuit, that 5 billion is still a drop in the bucket to what Google has made on the collected data.

Remove Chrome and its daemons. Never install it again.

vasileios225 wrote:

• Used a LACIE HD external drive to load another LARGE PHOTO TIFF FILE 350MB / no improvement

• Downloaded AFFINITY PHOTO, a photo application, and yes I confirm that LARGE TIFF FILES open instantly!! But I have noticed that a 500MB TIFF FILE opens as a 100MB FILE with AFFINITY! So this could be misleading

So the basic problem with PREVIEW remains and I am now suspecting the graphics card! My iMac is still covered by Apple Care, but I would imagine that I would have some hard time to convince them to replace the card, especially after they have declared the iMac as OK, passing all diagnostics successfully!

All of these file sizes are irrelevant. I don't know what you mean by "opens as". Let's circle back around here. Where are these TIFF files coming from? Can you download a similarly sized TIFF file from some public source and experience the same problem? If not, then the problem is likely in the file.

Apple didn't name "Preview" incorrectly. It's not "Apple Super Pro Photo Editor". It's "Preview". It's not going to open every file under the sun. It's designed to open those cute AI-generated files that people post on Facebook - and that's it.

And yes, I've done it once again. I've asked more than a single question in a post. I don't understand why people feel that it's easier to erase a computer, restore the operating system, and take it to Apple for hardware repair than to simply respond to a question or download a file from the internet.

What you describe is, indeed, well within what most people would call "total failure". However, it's really odd that you would experience this kind of 1985 performance only on one specific operation with one specific kind of file with one specific app. And you haven't noticed any other anomalies after using this computer for some unspecified "long standing" amount of time? Again, really odd.

I'm afraid there is one, and only one explanation for this. Your TIFF files are corrupt or unusually encoded to the point where one specific, consumer-grade, known-buggy app is struggling to open them. And you think replacing internal components with some factory-return, second-hand refurbished parts is going to fix it?

Per etresoft, we need to back up a bit. Forget hardware for the moment.

As mentioned, Preview is a free, and is (let's just say it) a junky app. It is very simplistic and has never been very good. There always seems to be something goofed up from one major upgrade to the next. Such as about five OS versions back, if you opened a CMYK image, it either displayed green or solid black.

It wouldn't be an unfair guess to say the version of Preview in Sequoia has a bug the Ventura included version does not. Which could easily be the reason you see such a difference between them. Especially when Affinity Photo opens the exact same image instantly.

Try this. Open the image in Affinity Photo. Choose Export (an export is the only way to save a non-native Affinity file format from their apps). Choose TIFF as the format and save it with a new name to the desktop.

Now, open that newly exported TIFF in Preview. Does it still open glacially slow, or does it snap open?