GregoryOR

You have mixed color space (RGB and CMYK) images placed in a CMYK document with the default US Web Coated target profile. All images however are relatively low res so it is unclear whether CMYK output is really wanted, but let us assume that CMYK was really intended. The PDF created is also mixed color space file, and retains the involved transparency of the topmost image so the color values have not been resolved. 
How the color values will be resolved when the image is ripped (and the transparencies flattened) at print time will depend on in which transparency blending color space flattening will happen. Affinity apps do not allow the user to explicitly specify this, but there are ways to resolve the problem so that you more or less get what you see and can reasonably expect.
One part of the problem is that whenever you use CMYK document color mode, everything in the document will be shown as if proofed to simulate the target CMYK profile, and this view is not necessarily realistic as regards the final output you will get. 
One way to resolve this is to explicitly export to CMYK color space and additionally use "Convert image color spaces" option:

This still leaves the file somewhat ambiguous, leaving the transparency blending color space in RGB mode, but the result on paper would already be pretty much what you expect based on what you see on the display:
SketchTest_master_forced_cmyk.pdf   
The safest choice is to flatten transparencies, either by merging the involved raster images before exporting, or at export time, using either PDF/X-1a or PDF/X-3 based exports, which both do the job. Using PDF/X-1a will make the exported file DeviceCMYK, while PDF/X-3 can optionally leave non-flattened images in RGB color space.
SketchTest_master_pdfx1.pdf
SketchTest_master_non_forced_pdfx3.pdf
Without having PDF preflight tool like Adobe Acrobat Pro, IMO it is safest to go with PDF/X-1a, but there are some serious flaws [within Affinity apps] with this production method whenever placed PDFs are involved, or when needing to flatten vector-based transparencies. Neither are involved in your job, so forcing flattening and going DeviceCMYK is a safe choice.
 

+1 for me.  Transform objects separately is a great feature that I just read about on this thread, but it resizes proportionately, and I would love to resize all to the dimension I type in the Transform text field.

Thanks for the suggestion. I tried deselecting "Enable Metal compute acceleration" in settings under Performance>Hardware acceleration, but there was no change in the behavior.

A key object can be nominated for the alignment. After at least two objects have been selected, opt/alt-click (in the view or Layers Panel) one of them to mark it as key - its highlight will be thickened in the view and become brighter in the Layers Panel.
 

+1 for me.  Transform objects separately is a great feature that I just read about on this thread, but it resizes proportionately, and I would love to resize all to the dimension I type in the Transform text field.

Hi Lewis. Put your text frames on the master page - Publisher doesn't create them for you automatically. If using facing pages, link the left and right text frames together.
Then, with just page 1 in your document (don't create more pages manually), import your text into the frame on page 1. That frame is from your master. Shift + Click the overset text icon and Publisher will create all of the additional pages required and link all the text frames together for you.
More information here:
https://affinity.help/publisher2/English.lproj/index.html?page=pages/Text/flowingText.html?title=Flowing text through frames https://affinity.help/publisher2/English.lproj/index.html?page=pages/Text/linkingTextFrames.html?title=Linking text frames Cheers

It's been added in beta. It'll be in 2.1 when it's released.

Yeah, @Xakiru, I saw your post as well.  Wasn't sure which thread it belonged in, but in this thread, it was supposedly being bumped up to the dev team in 2018, if it is indeed, the same bug.  Could be user error though, so wanted to confirm first.
@walt.farrell, I'm using 1.10.6.  File attached.
Thanks!
PaddedPNG.afdesign

I would prefer that the 3 options (selection, selection area and document) have different keyboard shortcuts, kind of like all the different kinds of paste options.  I always use opt+shift+cmd+s to export.  I'd be happy to learn a new combination to export selection.  Since I use that option roughly 99.99% of the time, that would be the only export shortcut I would need to memorize.

Go to the Layers panel, select the image layer and click on the 'Blend Ranges' gearwheel at the top of the panel. In the Blend Options dialog that pops up, drag the left-hand end of the Source Layer Ranges graph all the way down to leave white text on a transparent background.

I put together a quick video that can get you started but is by no means a comprehensive tutorial. I do go over using Add Noise and Levels.
 
 

Sorry to be slow in making a reply. Sure, you can have the letter "S' in an improved version. I've been working on a whole alphabet in caps, and when finished, if anyone want it, they're welcome to it.
 
I'm learning a lot, not only about AF, but fonts and chiseling. I've become much better at breaking the font letters into chisel cut sections. Still not quite clear on what the carving standard in reality is, if there is one. Also, fussing w. adding chisel marks within the cut sections.
 
For now, I hope the portioned letter shape can be made to work w. gradient effects to simulate light from a specific direction.
 
Letter_S_parted.afdesign