Precisely copy and paste?

[CarrotMan]

I can't seem to get an image to precisely fit over another and would appreciate some guidance. 

I've combined 3 raw exposures of the same scene (+1, 0, -1 EV; shot with tripod) in HDR merge. I should really have taken another, darker shot too, because the highlights are still a bit blown. So I've taken the darkest raw again, and reigned in the highlights. If I copy and paste the HDR merge over this darker layer and then use the Blend Options Underlying Composition Ranges tool, I can get the result I want exposure-wise. The problem is that I'm clearly not overlaying the HDR layer precisely over the darker layer, because I'm getting a bit of ghosting (first image), and in fact I can see a little "checkerboard" pattern to the side of the image . It should look like the second image. (It is a whitewashed stone column behind a wooden bench). Please excuse the poor laptop screen images snapped with iPad. 

Thanks,

Julian

[John Rostron]

2 hours ago, CarrotMan said:

I've taken the darkest raw again, and reined in the highlights. If I copy and paste the HDR merge over this darker layer

Do you mean that you have re-photographed this darkest image, or that you have re-developed your original raw image? You can stack  your new image along with the HDR image using File > New Stack  and tick the Align box. You can then possibly use the minimum option for blending, otherwise use the Blend Ranges as before.

If you have a revised image, why not start again with the File > New HDR Stack?

Your images as posted would have been better done with a Screen Grab. On Windows, use the Snip tool.

John

[lepr]

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[CarrotMan]

Many thanks John. I will try this. Presumably align will align everything perfectly. The blend ranges seemed to do the trick. I was very happy with the conversion I had made until I noticed the weird ghosting. I will try again tomorrow. I’ve spent too long on my laptop today and am going cross-eyed! Thanks too for the tip about the screen grab. I do screen grabs all the time on iPad but I couldn’t think how to do it with Affinity open on the laptop. 

Julian

[CarrotMan]

Thanks for the tip about lens correction. I think I re-opened the HDR merge in Develop to use the CA removal tool, but I will try developing each file individually and then merging them. I’m on my iPad at the moment and haven’t got access to Affinity, but think I can only access the CA removal option in Develop, but that defringeing is available in both Develop and Photo? To get rid of all the fringeing I had to use both tools.

Julian

 

[John Rostron]

1 hour ago, CarrotMan said:

Many thanks John. I will try this. Presumably align will align everything perfectly

As Osgood Fielding III said in Some like it Hot,  "Nobody's perfect!", not even Affinity alignment. It will depend on there being well-defined objects/edges for the alignment algorithm to work on. It does work well most of the time.

John

[CarrotMan]

Thanks John. I suppose it has done a pretty goog job in that case, because the edges are just the fuzzy edges of weak shadows in brighter patches. I wonder whether I might be better to try what I originally thought of, and create a selection around the most blown out area, then just apply the Blend Range manoeuvre to that. Precise alignment would then be pretty irrelevant. I’m really only trying to rescue a fairly small patch of totally blown-out white.

 

Julian

[John Rostron]

14 hours ago, CarrotMan said:

create a selection around the most blown out area, then just apply the Blend Range manoeuvre to that.

I would suggest that you create a feathered selection from your revised (not-blown-out image), copy it and paste onto your blown out image. Set the opacity to around 50% and align it manually. They you can restore the opacity and apply Blend Ranges as you suggest.

Could I also suggest that when you refer to others (such as myself), you use the @ style format. Type in the @, then begin to type the user name. A list of possible names appears below. When the correct name appears, click on the name in the list, If you did it for my name then I would get a notification of a response.

John

[CarrotMan]

@John Rostron

Thanks for this tip, John. I will try it.

Thanks too for showing me how to answer correctly. I did try quoting, as on some other fora, because I wanted to answer you specifically, but thought I was doing it incorrectly, so I’m glad you put me right.

Julian

[CarrotMan]

@John Rostron I think that the non-alignment issue was almost certainly because the darkest raw file, which I was trying to put beneath the HDR merge, seems to have had a slightly smaller pixel size for some reason, than the HDR stack layer. It may be because DPP had apllied lens correction but AP hadn’t (only CA and defringe). I think this is what the poster in post 3 is suggesting. Certainly DPP can make quite a noticeable difference to what appears in the image after lens correction is ticked. I think that DPP preserves all the lens correction parameters once applied until re-set.

Julian