«

[Talkie]

Hello,


It's been a long time I ever asked for technical
help on a forum. I'm a little lost right now
about where to ask, but the problem started
when I realized recently that anything in
Dosbox would be slightly darker in fullscreen
mode, not enough to not be able to play, but
enough for it to be annoying.


I then realized that my computer also gets "darker"
when I change the screen to a lower resolution.
Recently, I had played with my NVDIA settings
to get better brigthness and colors, so maybe
I switched something wrong, but there was never
any difference of brightness before when I switched
resolutions.


In a standard Dosbox config, when I switch
full resolution and windows resolution to my
current computer resolution (1152X864), and
change output from "surface" to "overlay", the
image is perfect. That's nice, but doesn't explain
my problem, and not helpful if I want to run
a Win95 Cd in 640X480 resolution (right now I use
gapa to change the brightness, but I didn't need
this before).


Does this problem ring a bell to anyone?
I could just put all my NDVIA settings to
default, but I want to wait before I do this
to see if there is something else I'm missing.
Thanks!

[Scatty]

Just a guess, but maybe you changed the color channel from all to any one of the three, or the graph in color settings. I never really touch those as the brightness on my laptop is good as it is.

[Japo]

How big is the difference? It can be normal when resizing and applying anti-aliasing that the color gamut gets shifted a little bit.

[Talkie]

Thank you both for your replies.


Scatty:

I checked, but all channels are ok in
NVDIA (you mean red, green and blue,
I think?).


Japo:

If you open gapa, and play with the brightness,
it's like 10% less than 0%. I had never seen such a change
before, and it's annoying enough that colours aren't
fresh. It's like noon looking 7 PM in The Black Gate.
(if you get my drift, lol).


Oh, em: What is anti-aliasing? ;-)

[Japo]

Originally Posted by Talkie

Oh, em: What is anti-aliasing? ;-)

Aliasing is something that can happen when you resize an image, and to fix it anti-aliasing is applied, which can have other modifying side effects.

https://en.wikipedia.org/wiki/Aliasing

Flat screens have only one single resolution, as opposed to old CRTs, so every image is resized to this native resolution. This can be done by software, by the graphic card with whatever settings you have, or by the screen itself if it finally receives an image at a different resolution.

[The Fifth Horseman]

I actually seem to recall old CRTs displaying different brightness depending on resolution.

[Eagle of Fire]

From personal experience, some screens need you to play with the screen option system which is incorporated inside the screen itself and cannot be modified directly thru the OS. Other screens also "remember" different settings for different resolutions.

My advice would then be to try to change the brightness directly on the monitor when you switch to fullscreen or other resolutions and then check if the brightness of your native resolution is affected by this change.

[Talkie]

Thanks, you guys. And I do am using an old
quite large CRT: I just love the "retro" experience.
I just never noticed as important changes in brightness
as of very recently.

I'll look into what anti-aliasing cause might have this effect,
but just to respond to Eagle Of Fire: that's a weird thing, in
that when I use Gapa or NDVIA settings while in Dosbox (or
different rez) and adjust the brightness or gamma, I get a
"whitewashing" effect (or polarization, not sure how to say it).
At max, the screen gets all greyish instead of white, like the
screen refuse to "lighten up", in fact just like a dying monitor.
But if I switch the resolution within Dosbox config, the screen
is as bright as it normally is. So I'm discarding the possibility
that the monitor is simply dying, but...


I see something about "augmenting the PPP" parameters
in the screen prefs, but not sure what it means.



EDIT:

Fixed!!!!

Ah well, it's a little embarassing, but...
It's just the monitor refresh setting in NVIDIA.
It was at 60 hertz. Switched it back to 85 or so,
and everything went back to normal (no diff
whatsoever when switchng resolution). Only
weird size and pincushion effect to adjust on
my main resolution, but all is pretty now.


I recall having changed the monitor refresh
setting to 60 hertz, because of an obscure
Windows 3.1 Cd-Rom that was very difficult
to get playing, and the graphics were always
very polarized. Someone had suggested me
to change the Hertz, though later I realized
I just needed to toggle between desktop
and program to have the graphics look fine.
And of course I forgot about the 60 Hertz,
but maybe something else is involved because
I only noticed the problem above quite recently.


At any rates, in case anyone comes up with
a similar problem, you can check that or color
channelling first.


Cheers! And thanks!


Edit2: Well, ok, a couple hours later, I can notice a slight
difference in Dosbox from small window to fullscreen (using
ALT + Enter), but not as bad as before. The Dosbox image
is never as good as when I just config it to my current resolution. Something else I noticed about the text in Dosbox when it begins to run: when I ALT + Enter to fullscreen (or config to fullscreen=true and resolution to original), the text has slight lines into it, a little like a old "interpolated" monitor effect (I'm thinking of the graphic options in the emulator Gens), and it is slightly greyish, and when I just config to
my current resolution, the text is paper-white, very
vibrant and clear. It's probably always like this, but
I never noticed that before. I guess it's really best in
Dosbox to always configure to current resolution, but
then you can't reduce the window. Ah welll....

If anyone want to experience this, tell me if you see
graphic differences (in the quality of the Dosbox
command text when it starts). Thanks!

[Smiling Spectre]

Originally Posted by Talkie

when I ALT + Enter to fullscreen (or config to fullscreen=true and resolution to original), the text has slight lines into it, a little like a old "interpolated" monitor effect (I'm thinking of the graphic options in the emulator Gens), and it is slightly greyish, and when I just config to
my current resolution, the text is paper-white, very
vibrant and clear.

When you config it to "current" resolution, DOSBox interpolate screen to your resolution, "fixing" different gaps and everything. Of course, 320x200 or even 640x480 will be less spectacular on your big monitor.

But you can try to check DOSBox settings, "output" in particular. Maybe it will give you some difference, but I cannot guarantee anything.

Also, as already was suggested here, try to tune monitor - CRT ones usually remembers individual settings for every mode (resolution+frequency).

[Talkie]

Thanks, people.

Yeah, I should've mentioned my CRT (which is a late 1990's chunky
AOC model) always has its analog brightness at max, no matter what.
I just think we can be too demanding of old systems.

I hope the brightness change in Dosbox doesn't happen in
modern systems or I'll be thoroughly disappointed. I don't
see that change when I use other emulators (well, not
with Gens, and I'm talking of my old CRT again). It's very
head-scratching, that problem.

But really, the best solution (for an old CRT) is to config
Dosbox to current resolution: you get the clearest results,
and in fact I think I should have used this in the past,
because it all looks better than ever, now. It almost feels
like discovering SVGA over VGA. I'm surely exaggerating,
but it's like I wiped-clean an old dusty monitor after I
do this.


Cheers!