Hi David,
Welcome to the forum.
Yes, it is simple.
You can view an image full screen by hovering the mouse over the thumbnail and pressing the space bar. To soft proof. hold CTRL and press the space bar. Successive pressing of the space bar will then switch between soft proof and normal view.
Of course this requires a good monitor profile to be set up in QU and the appropriate printer profile to be set too.
You mentioned "filters", it's nothing to do with any "filter" but double conversion of the image to the printer profile and then the monitor profile. Double conversion does mean soft prof can be un-reliable. You cannot beat a real print!
NB. the term "filter" in QU refers to image edit filters that enable non-destructive editing of images.
Any more questions, just ask here  
Terry

Fred and Terry,
Thanks for the replies. But from your replies, I can see that I wasn't clear in my question.

I understand how to look at the original image and the simulated (soft proofed) print image (<ctrl><space> while hovering over the thumbnail). I understand about the monitor and printer/paper profiles. I understand that the space bar goes between displays of the screen and simulated print versions of the image.

The question comes when the simulated image is not so good that it cannot be improved by making a modification to the file just so the printed image will be closer to the desired image. (I've often found that goosing the saturation, contrast or brightness improves the image especially when printing on fine art paper.)

When I mentioned filters, I was attempting to use Qimage terminology. As I tried to explain, in Photoshop, I would make an adjustment layer(s) and match a before and after (the one with the adjustment layer) to each other with the one showing the adjustments simulated printed copy. Then if I am printing, I turn that layer on and if I'm setting up the file for display on a monitor, I turn it off. If I am printing to canvas, the tweaks I make might well be different from those that I want to make if I'm printing on glossy paper which might be different from those I want to make if I'm printing on fine art matte paper.

I'm wondering whether the problem I'm having might be in the definition of soft proofing.

I think of soft proofing as conditionally adjusting an image for purposes of printing. I'm getting the feeling that that's not how Qimage defines it.

So I'm getting the feeling that there is no way that I can process an image so it looks good when set up for display on a computer display (presumably using a jpg for web or email) and then have some tweaks to that file that are only applied to the file when it's being printed.

If that's the case, I still kind of wonder what the point of soft proofing in Qimage is. It's got kind of a look-but-cannot-touch feel. ...or did I misunderstand your answers?

Thanks again,
David

This issue you bring up (see above) is not a Qimage issue, but a questionable  value to softproofing.
Qimage does it properly, and was added to satisfy the old PS users who wanted to use it and who thought it had purpose.


This quote is the crux of the problem, David

You see, the point is that we should end up with the same image appearance whether it is showing on a computer monitor, a projector, email, or a print.
Granted that a print is somewhat different as in the way it is lighted, but using a dedicated light source to view the print (like an OTT light), we should be so close as to be able to say it looks the same.
Colors, the same, tone, contrast, and saturation.

So what do I get from reading your second explanation (which I have to thank you for), is simply,,,,,  (and many of us go through this) The Print Doesn't Match The Monitor Screen.  

Now we pop back to Terry's point.   Profiling!!!    If you are determined to do this correctly, then you must have a correct Color Management loop.
Making your own printer profiles is easy. If you are into that, have one made for you commercially if you would rather not.

FineArt paper usually comes with a downloadable profile. What Brand?
What printer?
  
Hypothetical  :::      You use a profile, and you set the driver properly to the required settings for the profile, and the print still comes out needing more contrast, or more color, etc...
This says that your monitor is too contrasty and with that, too much color....  which causes you to improperly set your adjustments based on the monitor "LOOK".

But in MOST cases, the Print is correct, but the image you feed the printer is really flatter than you think it is.

Let's look at your other comment about web size or email images... they look ok.    Well, maybe because they are being judged on a too brightly colored monitor?

It has been done many times, successfully, I might add, where people make a test print using a test image, (I can email one to you if you need one) (Not colored squares) (I hate those) and adjust the brightness and contrast of the monitor based on a print.

In other words, David, I am suggesting that you accept my test image. Use the profile. Set the driver to the correct paper, correct quality, NO COLOR ADJUSTMENT, set to OFF, and make a test print using this image.
NO TWEAKING! NO Meddling!
Just print.
Now evaluate,,, looks how... looks perfect?
It should!  
Now you can judge honestly how far or close the monitor looks.

If you have been using a PS layer to compensate for printing only, it is likely you are putting a band aid on a problem that should be corrected properly.

... and yes, layers do the same job that Qimage filters do.  
Except that layers bloat the image and are clunky. Get to use Qimage (a learning process of course) properly, and it will feel like the first time you drove a car with power steering!!  

Now I will turn it back to my friend Terry, who can probably add more on this vein, and do a better job too.

BTW, Dave, don't mean to sound hard, but you did say you were looking for an alternative to Adobe.
If so, then you will have to divest yourself of some of the Photo Shop myths.

See some of the videos.... http://www.ddisoftware.com/qimage-u/learn.htm

Ask anything here and you will get honest answers.

Also, if you live in the US or Canada, I can call on the telephone for some one on one if you prefer.
Terry is in the UK if you live there.

Fred

David,
I took some shots a year ago of an outdoor train museum with old trains and some that still run and  are used for excursion rides.
There was a RED caboose. Lot's of cabooses are red. This was fresh paint red!
With my Epson R1800, that sucker would come out orangy .  
That printer recently died, and I replaced it with an R 2000 which has chrome ink plus a different color configuration.  It has an orange cartridge and a red and a magenta.
Now I reprint that caboose shot and I get the correct red.

Sometimes, certain printers have deficiencies, and can't be absolutely corrected.

I can show you how to make a print filter easily.... just want to make sure that you aren't using that in place of a proper printer profile.
Now that you explained that you do use a profile, we can move past that.
My email address is wathree.ssz@verizon.net
Let me know your phone number and the best time to call...   I am in Sarasota, Fl. Same time zone.


By the way, part of your problem is prophoto....

looking forward to talking to you.

Fred