Color Bar Program?

[Tempest]

Is there a nice color/gray scale bar generator for the Atari 8-bit that I can use to adjust my monitor?  Also something for maybe adjusting colors for artifacting?

[xrbrevin]

load the SALT program

 

Salt 2.04.xex

[Tempest]

Ah ok.  The reason I ask is that I'm using an Atari 800 with an Incognito set to XL/XE.  When using S-Video everything looks alright, but the color for composite looks off.  You can see it in this picture.

 

This is how Lode runner should look through composite (I think anyway):

 

This is how it looks on my 800:

 

Notice how the background is a maroon color and the lines around the title have weird banding issues?

[ClausB]

This gives grays. For colors change line 1 to GR. 11.

 

Edited December 22, 2019 by ClausB

[FULS]

Here is one in Basic that I used to use.

COLOR ALIGNMENT GENERATOR.bas

[Roydea6]

colorx.xex

 

horizontal color and then horizontal grey scale.

credit goes to ClausB and Fastbasic..

[Tempest]

Thanks, I'll run this on my 800 and take a picture of what comes up.

[Tempest]

Ok this is what I get. The colors look fine, but the last three or so greys are missing.  No amount of fiddling with my monitor would get them to appear.

 

 

[ClausB]

Looks like we'll have to change that resistor. ?

 

How is it on your other monitor?

[Tempest]

I'll check tomorrow.  I have a few I can try.

[Tempest]

I tried this on two other monitors: a 1702 and a sony PVM.  Both had less washed out colors than the JVC monitor I'm using and showed the two missing grey bars (kinda) but I'm not sure the colors were all correct.  I can't believe it's my monitors fault as that JVC is really good for everything else. 

[Faicuai]

For color-calibration only two utilities seems worth the effort and attention:

 

1. ACP

2. ColorMap from Altirra's extension disk / ATR.

 

When adjusting color-POT resistor, ColorMap is the way to go, because it shows a replica of Color hue/row 01 right underneath hue 0F, which is absolutely essential to ensure a progressive hue-scale that will yield 256 colors (not 240, etc.)

 

The 800 will highly unlikely deliver full on-screen dynamic-range without first replacing R189 for 200-220 Ohm. It is probably the sole and permanent video upgrade worth performing directly on main MoBo. This has been extensively mentioned, so far.

 

When adjusting colors, there are at least two (exclusive) rendering intents that will need to be individually chosen:

 

a) get as close as possible to 1980-1983 color renditions, or

b) get as close as possible to modern NTSC "correct" colorimetric rendition.

 

It seems, at this point, impossible to get both of the above. I chose a), and a quick test to determine if things are on the right track is SCRAM:

 

 

The key areas to check are the yellow-hue of first water-reservoir, the red-orange hue of the generator on the top-right, and the brownish info-window that the bottom.

 

In order to get the above rendition, ACP output should look like this:

 

Notice that such color rendition iS NOT error-free, as perceptual error has been shifted to hue-rows 0E and 0F, although ensuring 256 colors rendition. Titles that expected brownish-colors from hue 0F will be out-of-luck, such as award-winning Fernando Herrera's My First Alphabet (Cow, Queen, etc.) and others.

 

There are even more precise and objective checks of color-rendition, such as NATIONAL FLAGS program. Flags like Spain, Venezuela, Mauritania, Kenya and others MUST be rendered relatively close to their well-known appearance. If they don't come out correct, it is virtually guaranteed that your color-rendition is OFF (perceptually-speaking).

 

Lastly, saturation-wise, colors should come out rich and creamy (not "bright" or "electric" looking). A rendition of GTIA rainbow should look something like this:

 

 

As a side note, you can compare the difference between a synthetic rendering via emulation (my Avatar) vs. actual HW on analog-to-digital video-path. Notice the significant difference in color density and overall vividness.

 

F.

 

 

 

Edited December 26, 2019 by Faicuai

[Tempest]

Wow, thanks for the in-depth tips. I'm sure they'll help once I get that resistor replaced.  Is there a dsk or xex for SCRAM?  All I can find is a cas file which does me no good.  Also where can I get the ACP program?

 

Any tips for composite? When I tried out my 800's composite (for games with artifacting) it was rather dark and muddy.  I know composite isn't the best, but it should have looked better than that.

[Tempest]

I found another color bar program here and here are my results

S-Video

 

Composite

 

 

As you can see the second bar should be yellow but it's a light green/yellow on the S-Video and actually light green on the composite.  The fourth bar is supposed to be a nice green but it's more of a blue green.   I assume this means that there's something wrong with the color pot on my 800?

 

[Faicuai]

With respect to your attempts, above:

 

1. I have already tried the synthetic SMPTE approach, and it will require a) good generation of R,G,B primaries, and b) a BLUE filter to confirm optimal HUE adjustment. There is even a Turbo-Basic program for it, with an on-screen real-time. Even though I have several BLUE-filters (as well as RED and GREEN ones, for saturation), our Ataris do not really generate R/G/B primaries (nor a 75% brightness reference-level) with enough accuracy to run this calibration reliably. Furthermore, color calibration on the Atari involves a mandatory color-POT adjustment (with a minimum warm-up of 180 minutes), and the color-charts required for that adjustment are different (and sufficient, on their own). You could run these pluge-tests as FINAL confirmations, though, instead of the starting points (that would assume you chose path B, which is colorimetric accuracy of modern NTSC color decode).

 

2. If you chose Path A (e.g. reproduce 1980-1983 titles as accurate as possible), you will need to (first) RETARD phase (dial a negative HUE) on your monitor or video-processor, in order to get HUE 01 (on ACP chart) "GOLD" color (not greenish-yelow). THEN follow with Color-Pot adjustment, so you get 1) Hue 0A as blue-grayish (Start Raiders shields) and 2) Hue 0F moss/muddy so it distances itself from plain-green but does not fuse itself with Hue 01 (GOLD). If your monitor already shows hue 01 as GOLD / GOLDEN, then no phase-adjustment is required (I would be surprised if the PVM requires phase adjustment).

 

3. There should NOT be any HUE or LUMA difference between s-Video and Composite renderings. You need to make sure your monitor is not holding PHASE adjustments separately for each input-type (e.g. it remembers Phase for s-Video and then Phase for Composite). As a starting point, PHASE (Hue) adjustments should be exactly or very-close for s-Video and Composite. Brightness levels should also be very close, and maybe just a tad more Contrast for Composite. You will SURELY need to increase COLOR (saturation) and SHARPNESS for Composite. The image should not be darker, washed out, etc., it should just look similar to s-Video, but with intense reddish/blue artifacts (for rendering Flight Simulator correctly) as typical from 800, and a bit less sharp. Examples:

 

 

 

 

 

 

 

To the above extent, please NOTE that your LODE RUNNER (Composite) color background is the CORRECT rendering (perceptually speaking, in terms of legacy titles). It should also show identical on S-VIDEO.

 

I will try to post pictures of it later (I already tested it).

 

Edited December 26, 2019 by Faicuai

[Tempest]

Here are my Ultima IV pics.  My colors are different, but not 'wrong'.  In fact I think the greenish color looks more correct than the brown you have in your pics.  I wonder if it's doing XL/XE artificating because of the Incognito?

 

 

[Faicuai]

20 minutes ago, Tempest said:

Here are my Ultima IV pics.  My colors are different, but not 'wrong'.  In fact I think the greenish color looks more correct than the brown you have in your pics.  I wonder if it's doing XL/XE artificating because of the Incognito?

 

 

 

In the same token, tree-trunks are not green (guaranteed).

 

However, it is better to look at the artifacts-rendition by firing Flight Simulator. A more accurate (real-life) rendition of Artificial Horizon should show BLUE and ORANGE-RED face. Any other color rendition is not true to its original intent.

 

You are rendering tree-trunks green because your Phase-adjustment is set for a different NTSC rendering intent. That's all.

Edited December 26, 2019 by Faicuai

[Tempest]

1 hour ago, Faicuai said:

 

You are rendering tree-trunks green because your Phase-adjustment is set for a different NTSC rendering intent. That's all.

Can you explain what you mean by that?  My monitor does have a Phase adjust but I swear it didn't do much, but maybe that was in S-Video mode.  Are you saying your brown grass pics are the correct ones?

[Faicuai]

17 hours ago, Tempest said:

Wow, thanks for the in-depth tips. I'm sure they'll help once I get that resistor replaced.  Is there a dsk or xex for SCRAM?  All I can find is a cas file which does me no good.  Also where can I get the ACP program?

 

Any tips for composite? When I tried out my 800's composite (for games with artifacting) it was rather dark and muddy.  I know composite isn't the best, but it should have looked better than that.

Seems I missed this one.

 

ACP: acp.xex

ColorMAP: colormap.com

SCRAM: scram.bas scramcod.bas

 

That should allow you to adjust and verify, accurately.

[Faicuai]

3 minutes ago, Tempest said:

Can you explain what you mean by that?  My monitor does have a Phase adjust but I swear it didn't do much, but maybe that was in S-Video mode.  Are you saying your brown grass pics are the correct ones?

Please, grab ACP from above link, and post a screen-shot.

 

I will confirm and explain, as soon as I can see it.

[Tempest]

1 minute ago, Faicuai said:

Please, grab ACP from above link, and post a screen-shot.

 

I will confirm and explain, as soon as I can see it.

Will do.  Give me a bit though. 

 

Can you run .bas files directly from the Incognito?

[Faicuai]

6 minutes ago, Tempest said:

Will do.  Give me a bit though. 

 

Can you run .bas files directly from the Incognito?

You would be better off inserting them on an .ATR with Altirra's Disk Explorer tool, and then copying this .ATR to your Incognito's CF card.

Another (quick) option is to mount your PC's directory of choice on RespeQt, as PCLink device (and then read from Atari running SDX 4.47+, by loading first PCLink device driver)

[Tempest]

Yeah I'll have to put it into an atr file then.  I can't believe no one has done this before as SCRAM is a classic game.

[Faicuai]

28 minutes ago, Tempest said:

(...) Are you saying your brown grass pics are the correct ones?

Yes.

 

Or said in a different way: if I want to make sure that Flight Simulator II's instrument panel (flying horizon) comes out rendered as it was intended, you will invariably have to extract brownish / orange-ish artifacts (not greenish).

 

Here are some samples from my flights on Cessna 172 and more recently on glass-cockpit Piper (you can see for yourself how an old and modern horizon-display looks, as well as colors):

 

 

Edited December 26, 2019 by Faicuai

[Tempest]

1 minute ago, Faicuai said:

Yes.

 

Or said in a different way: if I want to make sure that Flight Simulator II's instrument panel (flying horizon) comes out rendered as it was intended, you will invariably have to extract brownish / orange-ish artifacts (not greenish).

 

Here are some samples from my flights on Cessna 172 and more recently on glass-cockpit Piper (you can see for yourself how an old and modern horizon-display looks, as well as colors):

 

Nice!  I assume you know ClausB? He took me up in his plane once and it was amazing.  Flying a plane blows my mind, so much to know and understand...

 

I digress...  I'll get you those screen shots as soon as I can and I really do appreciate the help.  My goal is to get my 800 to have correct colors through S-Video and composite as close as possible.  I don't know if the Incognito affects the artifacting or not, but I'd like everything to be as authentic as possible.