How can I compensate for the fine dot pitch of a PC crt?

[Jack Burton]

So, my main gaming display these days is just a regular old run of the mill Dell E770p crt computer monitor. 

Running Soft 15khz with some custom modelines and it does a very good job of displaying arcade resolutions, but the scanlines are pretty thick.  If I set back from the monitor a good way it largely eliminate the problem and it looks very nice. 

But I'm wondering if I can't do some kind of trick with the screen sizing.  This is a fairly fine pitched monitor.  It's listed as being 0.27 mm and I believe it uses dot trios. 

What will happen if I use monitor controls and shrink the image?  If I'm right as the image shrinks the relative dot pitch will increase.  I know I can't get the real .78mm or whatever a 'true' arcade monitor will display, but I think I can probably get .5 and a big improvement in brightness and color by shrinking.  But just how much?

Right now I've got it shrunk about 3/4 of an inch on all sides and that is looking closer to "right". 

[qrz]

back off the focus a tad.

[Gray_Area]

If not qrz's suggestion (mind, remember to size the screen image back up beforehand), I suggest doing effects in software. Especially with the advent of the HLSL feature.

[MonMotha]

If you shrink it down to the point where you have the same number of scanlines across the same number of dots as an arcade monitor, it should look similar.  Unfortunately, given the drastic difference in dot pitch between a TV tube and monitor tube, the image will be tiny at this point.  It's also usually impossible to get the low res modes used by old games out of a PC CRT anyway unless you double the refresh (which can be an option).  Keeping the refresh rate the same will generally require the use of doublescan, which destroys any scanline effects in their entirety since each original scanline is actually two.

[Jack Burton]

Yeah, I'm doing the double scanned modes so I actually have real 384x224.  


I'm just having a hard time wrapping my head around the math necessary here.

I have a 17" display with a dot pitch of .27mm.  I need it to approximate the looks of a 19" display with a pitch of .50mm.  

I'm thinking that I need to do a little less than a 50% reduction in overall size of the image.  Just using some very rough calculations that translates to a 13" image on my 17" screen.

Doing that it just becomes way too small.  The pixels get smushed together, and a lot of detail is lost.  And not in the good way that comes from having an actual coarse-pitched display.  It just looks like you lost half the resolution.  

Ah well.  I'm going to leave it at 1/2" all the way around.  That's good and bright, and sharp as possible.  

[MonMotha]

224 lines doublescanned is actually 448 lines to the monitor.  It will draw 448 scanlines per frame.  What happens is that the video card simply scans out each line of the framebuffer twice.  Getting 100% authentic scanline effects using the monitor alone in this manner isn't going to be possible, but you may have some luck doing the double refresh trick (224 lines at exactly double the native refresh of the game to bring things within the 30kHz capable range of the monitor).

[Jack Burton]

I should have been more careful with my terminology.  I am doing double refresh, not double scan. 

My exact resolution is 384x224@119.4hz