Using the phone camera stand

 A couple of weeks ago I bought myself a 3D camera stand off of ebay.

At the time I said that the component fit was a little loose.

This means that the stand does not hold the phone at exactly 90°, which could lead to perspective distortion.

Using it to photograph small objects like coins this not a serious issue

any slight perspective distortion is hardly noticeable.

With larger objects such as postcards, it's a bit more of a problem

producing pictures where the top is a little wider than the bottom.

For practical purposes this does not matter, it's still perfectly legible for transcription purposes, but, aesthetically ...

Now I do a lot of my image transcription and manipulation on J's old imac, which runs Ubuntu, so any solution would have to be Linux based.

Googling mentioned perspec as an automatic utility, or as an alternative Darktable which is interactive, in that you manually select the image, run an automated perspective analysis tool, and then, if you like the result, bascially click on 'fix this please'.

After a little bit of trial and error I managed to produce this fixed image

which, I think you'll agree, is a bit better as regards perspective.

Quietly pleased, and certainly something I'll use again when preparing images for use in presentations and so on...