Can you pick another rendering intent? If you can, this product is kind of silly as how would you know what to pick without a soft proof? And if it doesn't allow other RI's, it's kind of silly that it doesn't.
Yes, you can select the rendering intent. And of course, it does change the color on the screen. So for a start, that answers your two questions here.
Soft Proofing (in both Spyder5Elite and SpyderXElite software) is a nice, advanced feature for anyone who wants to soft proof images through printer profiles.
It implements a full and technically correct color management workflow.
You can choose: any printer profile (and/or actually any other profile on the system if you want to cross-proof onto a different display or device profile). You can select rendering intent. You can turn out-of-gamut warnings on and off. You can toggle soft proofing itself on and off. Etc.
You load image file(s) into a list in the left side of the UI interface window and the file list (whether it contains one or many files) is the basis of which file(s) you can switch to, load, and view this way. The starting contents of the list are loaded from any individual file (or folder) on your system that you designate as the starting point (this is remembered between application launches). By default, it's set to load a single image into the list - the "standard" Datacolor set of 16 images - in this case, they're all part of the same large image file so that this "matrix" of 16 images is loaded as a complete set, and the initial scaling is best fit so that you see all of them in the viewer window.
While the window is open: you can drag-and-drop (or click buttons to load) any image(s) or folder(s) that you want into the file list. Image file(s) are appended to the list. Folder(s) will have their contents scanned and files they contain will be added to the list. (See notes on recursively scanning subfolders below)
ALSO (and this is a nice power user feature) you can change that starting point to any file or folder on your system; and if it's a folder, optionally, all of the subfolders can also have their contents scanned and added to the list recursively (this is either "on" so this happens, or "off" so that you only get the top-level items in the folder). So what you can do, if you want, is set up a folder structure of your own images, any way that you like, and every time you invoke this feature, ALL of the images in the top level folder and its children will appear in the list.
You can load images that are physically very large, by pixel dimensions. There's a VM system implemented under the hood so that images too large to fit in memory are automatically handled that with VM to whatever your startup drive is (an SSD is obviously a good thing here). On modern systems this would typically be the case only for larger than normal image files, such as multi-gigabyte TIFF files - but even in those cases, it does work; it'll handle multi-GB JPEG and TIFF if you want it to.
Once an image is selected in the list on the left, it gets loaded and displayed in the viewer section. Initially with best it scaling. You can use use the usual magnifier tool to zoom in/out and a hand tool to pan around. You can zoom in either by clicking, or by dragging a selection rectangle, and then the zoom expands the image crop to fit into the viewer. You can zoom way in, down past the pixel level, on images if you want (or more typically, zoom way in on very large/high resolution image files). You can immediately get back to best fit scaling to see the entire image through a tool click. (There are also keyboard shortcuts for all of these things).
Multiple displays are supported, including wide gamut, and/or mixes of wide and standard gamut displays. If you have more than one display attached, you can drag the Soft Proof dialog to a different display, it will automatically pick up that display's profile and adjust its color managed display accordingly. (You'll immediately see the effect of display gamut on highly saturated colors, as you'd expect to).
There's also a full-screen mode you can switch to which expands whatever you're currently viewing to fit the entire display, where you can use a key command to toggle soft proofing on and off.
Hope that answers questions about this particular feature.
David Miller
Manager/Lead Developer, Consumer Graphics
Datacolor