I am not sure if many of you who have used Lightroom's slideshow have noticed that getting the quality to look right on a smaller monitor (i.e. perhaps your client's monitor) than the one you process your pics on is not necessarily intuitive.
I have found that exporting the pics you want in the slideshow as the size jpegs you want in the slideshow is the first step, then import those jpegs as a child-collection of the collection (if you had one) you had for your slideshow. After importing these jpegs, then go to the Slideshow module, setup your template (if you haven't already), and export at the same size at 100% quality. This works great. Just before you size the jpegs to be either larger or the same size as what your client will see them at on their monitor.
I found that when taking the raw files (as modified in Lightroom) and going directly to the Slideshow and then exporting at the size jpegs, etc..., the sharpness that appeared in Lightroom wasn't coming out after I exported the pics and viewed them on my same monitor at 100% quality and at the same screen resolution.
Also, I think that you have to watch the PPI setting in the export module because it defaults to 240 pixels per inch. I think the export part of the Slideshow module uses this as well.
I am going to email NAPP and see what they say about this as well.
Any other thoughts?
Pat


