Cut out piece of photo softens, loses sharpness

[DanH]

 

Edit: Solution is given further below by DM1.

Process:

Load photo, rasterize so it can be cut with marquee tool, cut out desired area of photo, deselect.

At this point, all looks well. Then if I move the cut out piece of photo, or rotate it, the cut out piece of the photo softens or loses sharpness. Opacity is 100%. Normal blend mode.

Can be easier to see the issue if you have two copies of the cutout piece of photo, comparing the un-moved copy with the moved or rotated copy. Rotating might be expected to have a perceived difference of appearance due to square pixels having to change how they "describe" the image in response to a new orientation of the image (but perceived sharpness should not suffer), however, the softening issue still occurs even if the cut out piece of photo is simply moved up, down, left or right, without rotating.

Oddly, after moving or rotating it, if I realign it with an un-moved copy, the sharpness returns. Again, opacity 100% and blend mode normal.

Does this on iPad v2.0.3.321

Also on Mac v1.10.6

Perhaps I am missing something?

[Paul Mudditt]

1 hour ago, DanH said:

Process:

Load photo, rasterize so it can be cut with marquee tool, cut out desired area of photo, deselect.

At this point, all looks well. Then if I move the cut out piece of photo, or rotate it, the cut out piece of the photo softens or loses sharpness. Opacity is 100%. Normal blend mode.

Does this on iPad v2.0.3.321

Also on Mac v1.10.6

Perhaps I am missing something?

I am guessing you did not open the photo directly, instead you created a document then placed the photo into that document?

When you place an image layer it remains as a high resolution image regardless of how large or small you scale it. However, for any pixel operations to work on an image layer, you must first rasterise it so that the image pixels match the underlying document resolution. Sometimes this rasterisation is done by selecting an ‘image’ layer and then rasterising directly, and other times the image will be rasterised automatically for the tool you are using.

That is what is happening, you created a pixel selection and moved the selection out of the image, at that point it would be rasterised to the same resolution as your document which is of lower pixel resolution than your image.

The solution then is to increase the pixel resolution of your document  to avoid loss of sharpness. Use the hamburger icon then resize - document and try doubling the number of pixels to observe the effect in action prior to cutting out your image.

[DanH]

Thank you, although I opened it directly.

Like so: right clicked a tif file in a folder on my computer, chose from the pop-up menu: "Open With> Affinity Photo."

After some testing, looks the exact process I described is primarily a Mac v1 issue (don't have iPad v1 to test), but it sort of still is a v2 iPad bug too (read on to see why).

This exact opening, cutting, deselecting, moving process shows no softening in v2 (iPad or Mac) when I initiate this process on v2 apps. The reason I thought it was an identical issue with v2 iPad is because I am experiencing it on v2 iPad but only after using a file first created on Mac v1. The Mac v1 file was created and edited as previously described (in short: open image, cut, move, it then softens). Saved this file in Mac v1. Then opened this v1 file in v2 iPad. The softening effect persists when editing on the iPad. Not just the cut piece originally created in Mac v1. Using this same file in iPad v2, when I cut a new piece of the image, this new cut piece also softens when moved or rotated.

So, it sort of still is a v2 iPad bug, since it persists from a v1 file imported into the v2 iPad app.

Curiously, the same Mac v1 file opened in Mac v2 does not exhibit the same problem. It only persists when opened in v2 on iPad.

Note: I can create the same softening effect in v2 if I move or rotate a cut out piece of photo *before* I deselect. In v2, if I deselect first, then rotate or move, sharpness is maintained. But if I don't deselect, but first move or rotate, it softens.

 

[Paul Mudditt]

16 minutes ago, DanH said:

Thank you, although I opened it directly.

Like so: right clicked a tif file in a folder on my computer, chose from the pop-up menu: "Open With> Affinity Photo."

After some testing, looks the exact process I described is primarily a Mac v1 issue (don't have iPad v1 to test), but it sort of still is a v2 iPad bug too (read on to see why).

This exact opening, cutting, deselecting, moving process shows no softening in v2 (iPad or Mac) when I initiate this process on v2 apps. The reason I thought it was an identical issue with v2 iPad is because I am experiencing it on v2 iPad but only after using a file first created on Mac v1. The Mac v1 file was created and edited as previously described (in short: open image, cut, move, it then softens). Saved this file in Mac v1. Then opened this v1 file in v2 iPad. The softening effect persists when editing on the iPad. Not just the cut piece originally created in Mac v1. Using this same file in iPad v2, when I cut a new piece of the image, this new cut piece also softens when moved or rotated.

So, it sort of still is a v2 iPad bug, since it persists from a v1 file imported into the v2 iPad app.

Curiously, the same Mac v1 file opened in Mac v2 does not exhibit the same problem. It only persists when opened in v2 on iPad.

Note: I can create the same softening effect in v2 if I move or rotate a cut out piece of photo *before* I deselect. In v2, if I deselect first, then rotate or move, sharpness is maintained. But if I don't deselect, but first move or rotate, it softens.

 

Ah ok, think it would help if you can upload a screen recording and/or an example .afphoto file where you are seeing the problem. You can attach affinity files directly in your post.

[DanH]

Edit: this comment is no longer relavent because the explanation and solution is given below by DM1.

Well, I was mistaken. An almost identical form of the problem does exist when using v2 iPad when initiating this process within v2 iPad (and not only when initially creating the file on v1 Mac). Why I missed it may be because when moving the cut out piece around in v2 iPad, in some positions on screen it looks sharp as the original, but move it to another location and it might look soft. It softens and sharpens again depending on the exact location it is in. However, on the file created in v1 Mac I only observe it softening no matter where I position the cut out piece on screen.

Whether created on v1 Mac or v2 iPad, any apparent softness in the cut out piece remains when exporting to jpeg, so it's not just the way it is presented in the .afphoto file.

Being that I am working on photos of people I can't post here I might post a different photo later. But maybe not.

Easy to replicate, if you're interested. I am doing it with an eye (to replace a closed eye with an open eye.)

Perhaps another way to describe it, is the contrast lessens, rather than saying it is softer or less sharp. To my eye, both ways of describing it are saying the exact same thing with different words, at least when you're looking at an image at the pixel level.

My solution: apply unsharp mask to the softened cut out portion till it seems to match the original.

[DM1]

19 hours ago, DanH said:

in some positions on screen it looks sharp as the original, but move it to another location and it might look soft

 

This answer may address your issue.

 

 

[DanH]

Yes! Thank you!

When is it beneficial to have pixels not be forced in alignment? Edit: as noted by loukash below, probably not desired when working with pixels, but maybe sometimes when working with vectors.

Request for Preference setting: Edit: not necessary. See next two comments.  I'd like a preference setting that always forces pixel alignment even if I do not have snapping enabled. And then if some scenario requires un-aligned pixels I can temporarily turn it off.

For those just learning about this "feature" :

This fixes the issue only if "force pixel alignment" is enabled before cutting and moving, but not after doing it. So, if a cut is made, then moved, and pixel alignment is not being forced, then enabling forced pixel alignment at this point does not cause the cut piece to realign to the original pixel alignment. You'd either have to start the process over again, or alternately, you could de-select force pixel alignment, then manually try to move the cut piece until it appears to be as sharp as it originally was (at which point you have successfully moved it to be in the original pixel alignment). Then once in alignment, select "force pixel alignment" so all future movements of the cut piece will maintain its sharpness.

 

[loukash]

18 hours ago, DanH said:

a preference setting that always forces pixel alignment even if I do not have snapping enabled

Force Pixel Alignment is independed on snapping on or off, hence it has its own toolbar button. When you turn it on, it will stay on between launches. 
Unless you deliberately switch to a snapping preset that has Force Pixel Alignment set to off. In that case turn it on again and save it as a custom preset.

18 hours ago, DanH said:

This fixes the issue only if "force pixel alignment" is enabled before cutting and moving, but not after doing it.

Of course. This is "by design".

[DanH]

A toolbar button on the desktop version for forced pixel alignment independant of snapping? Perfect. Did not see that. Thank you!

The iPad version allows forced pixel alignment independant of snapping being on, but no toolbar button specifically for it (unless I am not seeing it). On testing it, I see that the toggle switch within the “snapping options” menu (next to the magnet icon in toolbar) turns forced pixel alignment on even if snapping is turned off. Unintuitive to me, but does what I’d like it to.

What use case is there for not having forced pixel alignment?

[loukash]

6 minutes ago, DanH said:

The iPad version allows forced pixel alignment independant of snapping being on, but no toolbar button specifically for it

My bad, I didn't notice this is in the iPad section. I'm reading forum posts in a custom "activity" stream where they appear chronologically, not sorted by forum sections.  

9 minutes ago, DanH said:

On testing it, I see that the toggle switch within the “snapping options” menu (next to the magnet icon in toolbar) turns forced pixel alignment on even if snapping is turned off. 

Exactly. It's supposed to behave like this.

10 minutes ago, DanH said:

What use case is there for not having forced pixel alignment?

Perhaps not much in context of editing photos.
But since Affinity is a universal document format for all three apps, and the exchange between apps is meant to be seamless (at least on desktop), the option not to align to pixel grid is important for vector work: Sometimes you may want exactly 11.1 mm, and that value doesn't necessarily match a pixel grid.