Using Refine leaves artifacts

[markimark]

I'm on Photo 1.10.6.1665,  I use Selection Brush Tool, noticed after cut and paste to new layer artifacts were left behind. So then tried Refine tools, set Smooth and Feather to a value that covers edges where artifacts were left.  Copy and Paste to new layer again and still seeing aritfacts, I also set Blend options 'force off' per some advise I saw somewhere.  I have very limited knowledge and want to understand why the artifacts are being left after cut and paste when I can clearly see that those areas are selected.  attached two screenshots of effort.

[markimark]

Also, if this is in the wrong discussion let me know, the forum has changed since I was last here and couldn't determine where to post questions per a product.

[Callum]

Hi Markimark,

This looks like it could be caused by feathering etc which settings are you using within the refine selection window?

Thanks
C

[GarryP]

markimark: When you make a pixel selection you are both telling the software which pixels are to be selected and how much of each original pixel is to be selected to be later copied/cut.

When you Refine a selection you can see in the Preview where there is a ‘gradient’ between the selected pixels and the non-selected pixels. This ‘gradient’ shows you how much of the pixel is in the actual selection.

By Feathering, Smoothing and using other settings you will get a different ‘gradient of selection’.

If you want to make a selection which has sharp edges then you can make the initial selection with Feathering set to 0px, as mentioned above, and not Refine it.

As far as I've been able to tell, it doesn't seem to be possible to Refine the selection without getting at least a small ‘selection gradient’ and leaving some ‘artefacts’, even when using the Basic brushes to do the refining – see attached video for a simple example (X/Y/W/H of pixel layer really are aligned to the pixels of the document, I’m using 3 decimal places in Settings).

I would be interested to know if it’s possible to Refine without these ‘artefacts’.

[markimark]

Guys, thank you so much for this explanation and help, more than I was hoping for. It does seem to be inherent in the Refine functionality, I would think this is something that would be great to hear back from Affinity development on, as to the logic of why it is coded this way, or maybe it's something they need to be made aware of for a bug report. 

@Callum  I was indeed using feather which seems to have been a mistake on my part, with this additional information I can play around with it.  Maybe what I should have done is extended select where I was over transparency and not use the Refine tool at all.

[GarryP]

The main thing that I don’t understand is why ‘some stuff goes missing’.

As can be seen in my attached video below, when I cut a selection from the original black square, and then paste it back into exactly the same place, some of the black colour has ‘gone missing’.

If I have a number and then subtract a second number from that first number, and then add that second number back to the result of the subtraction I would expect to get the original number. However, what I seem to get is the equivalent of: 100 – 50 + 50 = 98.

In the case of the black in my video I’m actually getting values higher than I started out with but it’s the same sort of problem but reversed – you can see the same problem if you use the same process with a white square instead of a black one (see attached image).

I can understand that we may be dealing with floating point calculations on integer pixel values but the result still doesn’t seem right to me and it’s not something I would expect – if I remove something and then immediately put it back exactly where it was I would expect to get the original thing as the result.

[markimark]

I submitted a report requesting this get sent to affinity dev team for bug review.

[GarryP]

Where did you submit the report?

[Leigh]

On 12/16/2023 at 8:22 PM, markimark said:

I submitted a report requesting this get sent to affinity dev team for bug review.

I can see that you reported the post. We'll get it logged.

[markimark]

Forum, I used the report function on post hamburger menu

[GarryP]

The “Report” functionality is (mostly) there to allow users to report to the moderators that a particular post may be in breach of the forum guidelines – e.g. bad language, inappropriate content, etc.

The normal way to make a bug report, or feature request, is to create a new post in the relevant forum section, preferably with a link to the original discussion in the Questions section.

When this is done, it’s easier for all users of the forum to be able to see that a bug-report/request has been created which they can then track (follow) if they want to be kept up-to-date with any progress.

You haven’t done anything bad, I’m just giving information about how you might like to do it if you need to do so in the future.

[Callum]

Hi All,

I have spoken to our QA team regarding this and they have told me that this is by design currently. When you feather a selection it will make a semi transparent selection and when stacking semi transparent layers on top of one another you will never get the sum of the two transparencies, so you're left with this halo effect.

Thanks
C