Asha

The Transform panel in the Studio will show the dimensions of the selected object. You can also use it to rescale objects.

I have been asking for this type of behavior for a long time.
Professional compositors, color calibrators, photo retouchers, use channels A LOT !
So, we need ways to deal with channels in a more flexible and powerful way.
I was told that it will come to it. Can't wait :D

I was exploring the channels a bit today. One thing I would have liked is the ability to directly copy the contents of a channel and paste them into a layer or a new blank channel. In other words, it would be more intuitive if the channels had behavior a bit more like layers. I was able to work around, but it was a bit tedious.

Just wanted to add to the already excellent replies--AP doesn't do focus stacking, which is one of the stacking features in PS. However, it is on the "frequently requested" list, so hopefully it will be added in a future release!

in general, a threshold setting defines a minimum value in an image's parameter for a filter to be applied. the higher the threshold, the subtler the effect, since it is applied to smaller portions of the image (the ones that fall above the threshold value).
if you think about the threshold filter, it allow to set a value in the tonal range (i guess) of the image: any pixel that falls below that value becomes black; any pixel above becomes white.
about the unsharp mask threshold, it is related to the difference between the original image and the blurred mask used to generate the effect. you may be interested in the "digital unsharp masking" chapter of the wikipedia article about unsharp mask (https://en.wikipedia.org/wiki/Unsharp_masking).

Welcome steve-halloween--there are both vector and raster tools available in Affinity Designer, so AD may be all you need. There is a free 10-day trial, so it is worth a try. If you need more options for pixel painting, Affinity Photo is great for raster editing, and it also has a 10-day trial.

I see there are many tutorials on YouTube, so I'm sure the OP can get some good info from there, even though it is usually PS that is featured. I watched a couple of them, and they can get to be very involved with many layers and masks. The basic approach I would take is similar to what JFisher wrote, and includes Madame's technique.
 
1. Create a duplicate layer of the photo and turn off the background layer
2. Create 2 child adjustment layers on the duplicate photo--1st, Black and White, 2nd Curves. Adjust the Curves so it is an S-shape to bring up contrast.
3. With the photo layer selected, choose Blur>Diffuse Glow, adjust to taste
4. With the photo layer selected, choose Filter>Noise>Add Noise, adjust to taste
5. Create a blank layer above the photo layer and fill entire layer with red using paint bucket tool
6. Change layer blending mode of red layer to Soft Light
7. Add a layer mask to the red layer, and make sure the mask is selected. Again using the paint bucket tool, fill the mask with black paint.
8. Make sure the red layer mask is selected, and using the paint brush and white paint, paint the areas you want to be red. If the red is too intense, you can reduce the opacity of that layer in the layers palette. You can also switch between white and black paint to refine the mask edge.
 
ETA: This can be automated when AP is updated with macro capability

I have been trying to use the channel separation method for selecting the tree, and in AP it is a bit convoluted, but it will allow you to get decent separation of the tree from the background. Here is what I did:
 
--convert the file to CMYK (for this photo, RGB and LAB did not have sufficient contrast in any of the channels)
--check for highest contrast channel--in this case it was the black channel
--duplicate the background layer and change the name to something more unique
--right click the black channel of the duplicated layer and select "Invert"
--right click the black channel of the duplicated layer again, and select "Create Grayscale Layer"
--add layer adjustment "Threshold" above the new grayscale layer, adjust so that tree is distinct from the sky, then "Merge Down" so the threshold is applied to the grayscale layer.
 
Since your file has a difference of exposure due to the backlighting, you may need to do 2 grayscale layers with different threshold settings. You can use editing tools to remove most of the the background way more easily once the threshold is applied, and you can use the finalized black and white to create a mask for masking or selection of the tree. Creating a mask has the added benefit of allowing you to refine it with powerful tools within the layers panel ("Refine Mask") to get even better edges around the tree.
 
barninga already answered the issue of the inpainting needed for your 2nd photo--that should be corrected before you merge with the first photo.

I certainly hope plugin support greatly improves.  I have an older copy of Photoshop that I have to hang onto in order to use any of a number of Photoshop-compatible filters and plugins.  I love Affinity and I'd like to never open Photoshop again but until plugins work in Affinity, I have to keep using it for certain processes.

AP 1.4.x is leaps and bounds above where Photoshop was at v1.5...

Actually, I was thinking about it--if there is a desire to have gradations in the mask based on the varying tone of the image, then selecting fully transparent won't work. I drew an airbrushed shape onto a transparent pixel layer, then chose Select>Select from Layer, which selected my shape with the feathered edges. Once the selection was made, I just clicked on the layer mask button to get a mask. It also works with the Quick Mask button at the top toolbar. Obviously, if the inverse is desired, then Select>Invert Pixel Selection should be done before the mask is made.

Does Select>Alpha Range>Select Fully Transparent get you close enough?

Everything is great but I'm wondering how making tool settings sticky is coming along? It's painful to retouch 20-30 images in a row and have to setup every single tool for every image! I'm still using it over photoshop but just remembering my flow settings or the current sampling layer setting would be really awesome.
 
Oh, also, it would be awesome if the lowest setting for opacity and flow on brushes was 1% and not 0%. That would make dragging to the left quickly to reach 1 - 3% a lot friendlier. As it stand sometimes you hit 0% and wonder why nothing's coming out.

I really only use photo editing software, but I occasionally use vector drawing software, and wanted to support the developer, so I bought both.

I really only use photo editing software, but I occasionally use vector drawing software, and wanted to support the developer, so I bought both.

PhotoNewbie, you can always paint on the highlights within AP ;)
 
ETA: For future photographs, I remembered this tutorial I saw on the web. The photographer achieves some truly wonderful lighting with some basic adjustments to his flash. http://neilvn.com/tangents/about/black-foamie-thing/

I really only use photo editing software, but I occasionally use vector drawing software, and wanted to support the developer, so I bought both.

Just tried out the masking with great success and satisfaction. Just what I wanted. Using black and white was the revelation. I'll check out the tutorials too.
 
Thanks all for the tips. 
Luke

Not yet. 
Will be possible when Opacity Jitter comes out.
 
In the mean time you can try these workarounds
 
https://forum.affinity.serif.com/index.php?/topic/11067-digital-painting-brush-opacity-pressure/?p=67292
 
https://forum.affinity.serif.com/index.php?/topic/11067-digital-painting-brush-opacity-pressure/?p=68992

That technique is called photo compositing, and there are many tutorials out there. Most will be for Photoshop, but there are analogous tools in AP. Here is a link that is generally about photo compositing:
 
http://www.zevendesign.com/photo-compositing/
 
There is no one way or prescribed order of steps, but the main gist is that you need to bring the new photo into a separate layer of the main photo, and mask out the background.

Hardouken, that thumbnail you posted looks like a glossy varnish to me. That is done in the printing stage. To prepare your file, you should have a 100% stroke on your circle in a special varnish color from your palette. It will be color separated similarly to how a Pantone color would be.

I fully sympathize with the issues of a "broken" CS6 and extortionate subscription for CC. However, I think the iPad has such a gaping hole with respect to professional illustration and photo tools, that it is very sound reasoning to try to get there ASAP.

My impression is that it is a quick way to get some punch out of a raw image before converting it to something like a tiff or native AF file. It reminds me of the sharpening control in Camera Raw. In that sense, I don't see it as being any better than the pixel based unsharp mask, but just convenient if you have raw in your workflow.

I fully sympathize with the issues of a "broken" CS6 and extortionate subscription for CC. However, I think the iPad has such a gaping hole with respect to professional illustration and photo tools, that it is very sound reasoning to try to get there ASAP.

I watched the stacking tutorials for the latest 1.4 release and didn't see one for focus stacking...hopefully that is a feature that is yet to come, and one I would definitely use.