Affinity Photo - Stacking to remove people leaves partial ghosts

[roadcone]

I have two Nikon raw files taken of the same subject from the same spot. Each one has some people on it but where there are people on one image there are none on the other.

When I stack the two files in AP and use the Median combine I am left with partial ghosts. They are neither complete people shapes, but only partial (for example, the left side only of someone), nor are they solid partials, but ghostly apparitions. I have seen the same effect with two different pairs of images, taken of very different subject in different locations (one was inside a museum and the other was of a statue outside a cathedral, with many visitors).

I know this works with both pairs because I have loaded them as layer pairs into Gimp and removed people from the top layer to reval spaces from the lower layer.

Can anyone offer any enlightenment please?

Clive

 

[walt.farrell]

You may need more images.

Consider that you have two images, and in one you have a person, and in the other (in the same spot) you have a sidewalk. If you take an average of the two (which would be the median with only two images) that area will be half person and half sidewalk. Basically, an 1/2 opacity person over a 1/2 opacity sidewalk.

On the other hand, if you had 5 images, where 1 had the person and 4 had the sidewalk, the median would be much closer to completely sidewalk.

This Serif Tutorial on Image Stacking for Object Removal may be helpful.

[roadcone]

Hello Walt and thank you for your prompt reply.

That makes a load of sense, and means that I cannot use the AP process for those two pair of images (actually, the one outside the cathedral used four, but there was still a shoulder of one person and a leg or hip segment of another).

Is there a blend mode other than median which would achieve the desired result? I guess not else you might have said.

Oh well, back to layer mask erasing.

Clive

[walt.farrell]

3 minutes ago, roadcone said:

Is there a blend mode other than median which would achieve the desired result? I guess not else you might have said.

I'm not sure, as I haven't used that function very much. The Tutorial might suggest other possibilities, but it's been awhile since I viewed it.

But here's a thought: If you one spot that's still giving problems, and one picture where that area is clear of people, you could select that part of the image, copy it, and paste it onto the composite after you finished the stacking operation.