Large image size

[swmcl]

Hi,

I am using flatpak 2.10 in Linux Mint 18.3.

My image size that crashes Gimp is around 1.9Gb.  My images are scans from large format photographs.   I scan at 4800 dpi and full 16-bits per channel.  I can scan images from the 3 common film sizes of 4x5 inches, 5x7 inches and 8x10 inches.  I am using a commonly available scanner, an Epson v700.  There is nothing terribly unusual about my setup.  I use Vuescan but can use other scanning software.

I am trying to show that I am not a completely unusual customer.

My 1.9Gb photo results in massive memory usage on disk by Gimp such that I had to re-install my OS onto a larger disk.  I was using a 120Gb SSD but now have shifted to a spin drive instead.  When I tried to do something simple like level shifting Gimp was using somewhere just less than 40Gb on disk ...

The Gimp program is extremely slow to do something like show a histogram at these image sizes.  My problem is 1.9Gb is a small image !  An 8x10 is around 11.2Gb potentially.

Recently, I tried Affinity Photo.  It loads my images almost instantly and any manipulations are smooth and perfectly quick.  It also has no limitations to image size well beyond the 8x10 size (according to a moderator on their forum).

Affinity Photo is not able to use my Nik software plugins so I am not feeling like switching to them yet.  Also I would like to never use a Windows machine again in my life.

I have waited for Gimp to be a serious competitor to Photoshop for years ... make that decades ...

Any idea when these issues will be just a bad memory ?  (given that it has taken something like 15 years to get to 16bits per channel)

I would pay for Gimp.  I do not believe that software needs to be free of monetary cost but I do believe in open source for security reasons.

I would donate images to developers if they didn't have any of this kind of size.

Cheers to you all.

[b60]

I have zero problems using Gimp with Windows!

As I understand it (I do a lot of scanning and photo editing with Gimp but I'm far from an expert) there's no real reason to scan beyond 600 dpi for the print sizes you refer to. If you want to make really large prints you can up it to 1200. Do a search for this information!

[b60]

(11-12-2018, 05:54 PM)b60 Wrote: I have zero problems using Gimp with Windows!

As I understand it (I do a lot of scanning and photo editing with Gimp but I'm far from an expert) there's no real reason to scan beyond 600 dpi for the print sizes you refer to. If you want to make really large prints you can up it to 1200. Do a search for this information!

I just opened a photo in Gimp about 8200x2500 and just to test it I scaled it up to twice that size--no problem at all. Gimp will give you a warning but it will still do it.

[Ofnuts]

Well, you don't state two important things: 1) the amount of RAM you have, 2) how big the tile cache is set in the Preferences>Environment.

Your 4"*5"@4800DPI is 460Mpix, so 2.8GB in memory (assuming no alpha channel). In practice you can double that (2.8GB for the layer, and 2.8GB for the composition of the displayed image). As soon as you change something, Gimp makes copies of the layers, so the memory usage grows fast.

Is this color film? Using grayscale you divide your memory needs by 3.

I wonder what kind of photographic emulsion warrants 4800DPI... And if the V700 can scan at 4800DPI, is that really twice as accurate as the 2400DPI scan? And is the 16-bit channel depths true 16-bit, or is it 8-bit padded with 0s, or 8 bits of usable value and 8 bits of innaccurate noise?