said jrickards:
| HI:
|
| I have about 20 photos (tripod mounted) that I'd like to blend. I'm | running Linux Mint 19.1 and I know that my laptop, having only 4gb ram | at the moment, is rather weak but let's just go with that. |
| I have tried something similar in the past and it failed so I moved on. | I was exporting from darktable into PNG format and then importing as | multiple layers but I'm wondering if, because JPG files are smaller (not | as good quality as TIFF or PNG even tho I set export quality to 100%), | would my system handle these images better in JPG format? |
| Alternatively, if I have 20 images, could I blend 4 groups of 5 at a | time, then blend the 4 groups into one image, would that be a suitable | compromise. Yes, more steps than blending once but if the result is | similar, for the sake of my system's limitations, might this be a | reasonable alternative method?

if you're using any transparency, as "blend" implies, you'll need to use png -- jpegs don't do transparency. also, png is or can be lossless, unlike jpeg.

dep

Some pictures:
http://www.ipernity.com/doc/depscribe/album

On Thu, 2019-09-05 at 22:41 +0200, jrickards wrote:

but I'm wondering if, because JPG files are smaller (not as good quality as TIFF
or PNG even tho I set export quality to 100%), would my system handle these images better in JPG format?

No. Once ncompressed into memory they are the same size. You may save memory because JPEG images do not have a transparency channel ("alpha"), but if your PNG files are saved without alpha there will be no difference. The jpg files might load into GIMP slightly more quickly.

Alternatively, if I have 20 images, could I blend 4 groups of 5 at a time, then blend the 4 groups into one image, would that be a suitable compromise.

It depends on the compositing (blending) function. Try and see?

For using GIMP on large files with low memory, experiment with setting the "tile size" in preferences to e.g. 3GBytes, and making sure no other programs are running (e.g. no Web browser, word processor, database server...).

Many laptops can be fitted with additoinal RAM, and this is often a cost-effective upgrade - assuming it's a 64-bit OS. Sometimes you can even find a similar model of laptop on eBay more cheaply than the cost of the memory in it.

slave ankh

What type of blending are you looking to do? Is it manual blending with masks in GIMP or combining multiple exposures for some other reason?

I only ask because if it's multiple stacked images to create HDR there's other tools that might be better suited for the job (LuminanceHDR to create an .HDR file, or even something like Enfuse for exposure fusion).

On Thu, Sep 5, 2019 at 8:08 PM jrickards wrote:

Many laptops can be fitted with additoinal RAM, and this is often a cost-effective upgrade - assuming it's a 64-bit OS. Sometimes you can even find a similar model of laptop on eBay more cheaply than the cost of the memory in it.

The Crucial memory website indicates that I can add another 4GB and I will but
for now, this will have to do.

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