Correcting distorted rectangle

[John Dowell]

I've a pic of a poster but the camera wasn't parallel to it so the shape is distorted – it's wider at the top than the bottom. It's easy enough to rotate it or stretch it but how do I undistort it? I tried the way I would have done it in Photoshop but that didn't work and I've watched all the videos that might have given me a clue.

Edited November 26, 2020 by John Dowell
to make the problem clearer

[GarryP]

The Perspective Tool or Mesh Warp Tool, or a Live Perspective Filter, in Photo might be useful here but I don’t know how ‘clear’ the result will be.

[John Dowell]

Thanks. The perspective tool sounds obvious but I can't get anything to happen. At the bottom of the screen it says drag handles to apply perspective, but I can't see any handles to drag!

[PaulEC]

Click "Show grid" and change mode to "Source".

[John Dowell]

I've clicking show grid, but all it does is show a grid. Still no handles!

[PaulEC]

Just click on the corners. Move them to the corners of the picture. Click "Apply"

[markw]

Well, something odd has happened there?
You should have a white bonding box around the image with a white node/handle in each corner.
Have you tried just restarting AP?

[John Dowell]

I've tried restarting – still no handles

[PaulEC]

That is odd, the grid should just be on the image!

[Alfred]

Just now, PaulEC said:

That is odd, the grid should just be on the image!

Yes, given that the grid extends way beyond the document bounds it’s hardly surprising that the handles aren’t visible. I think we need to see what’s selected in the Layers panel.

[markw]

8 minutes ago, Alfred said:

Yes, given that the grid extends way beyond the document bounds it’s hardly surprising that the handles aren’t visible. I think we need to see what’s selected in the Layers panel.

I was just about to ask the self same thing!

[John Dowell]

Sorry – I'm not sure what you mean by the layers panel unless this is it – I'm very new to this after using Photoshop for 30 years.

[PaulEC]

Same as in Photoshop - a panels showing the layers used in the image, with thumbnails. (Usually on the right).

[MickRose]

Accessed from View/Studio/Layers

[markw]

@John Dowell In your screenshot;  click on the tab marked Lyr next to the Adjustments tab you are currently showing on the right of your screen.

[John Dowell]

OK thanks  – got it. The writing is so small I didn't recognise Lyr as the layers panel. There's only the background layer. But I've now found that if I save the cropped file then reopen it before using the perspective mesh it works OK, which seems a bit odd. Do I have to save the file after using each tool?

[PaulEC]

The cropping is non-destructive. You don't need to save and reopen, just flatten it.

[firstdefence]

Once straightened be mindful of the original dimensions of the poster, because straightening will likely distort the aspect ratio of the poster. measure the poster and change the height and width accordingly.

[John Dowell]

Thanks – I realise that. Constraining helps. And now I've discovered that I can colour the grid to make it visible I think I'm getting there. Thanks everyone for your help.