Jump to content
mthompson

--gfx-palette flag

Recommended Posts

Stupid question, but has any component inside the Intellivision aged in the past nearly 40 years so those would produce slightly different colours today? Would replacing said components then make a difference on what you see on screen?

 

It's conceivable. I'm not sure how likely it is, though, at least for NTSC units. Typically, you worry about electrolytic capacitors, and there aren't really any in the video path. There's a 200pF (or 220pF, as I've seen on one board here) ceramic capacitor on the board, and some smaller ceramic caps inside the RF modulator. IIRC, ceramic caps don't have quite the same aging issues that electrolytics do.

Share this post


Link to post
Share on other sites

 

Doesn't Frank have one? Perhaps he'll be willing to help.

 

I'm sure he would. He's quite busy also these days, and at present I believe he's traveling for awhile.

 

I've certainly kept him in the loop on my investigations.

Share this post


Link to post
Share on other sites

Interesting. Don't have anyone here a capture card so colors can be get that way?

 

I don't, but I worked with someone who does. That said, the capture card produced results that were objectively different from what I see on my own TV, specifically on the more problematic purple and magenta, as well as a slightly-too-dark grey. NTSC's nickname "Never The Same Color" is well deserved.

  • Like 2

Share this post


Link to post
Share on other sites

A couple thoughts:

 

Any set of colors on an NTSC TV will be at least a little subjective. One advantage PAL has over NTSC is that PAL can accurately transmit color information such that it will look the same on any PAL TV. NTSC cannot do this, which is why all NTSC TV's have a tint control. NTSC stands for National Television Standards Committee, but it's also been referred to as Never the Same Color. I had no problem achieving a true brown, for instance, merely by adjusting the tint. The nice thing about a direct numerical conversion is that you are calculating what it should look like on an ideal NTSC TV.

 

Much of the color bleeding you see on TV's has a lot to do with how color information is encoded in an NTSC signal. The color bandwidth is far less than the black-and-white bandwidth. I'm not sure if it's an exact division by two or by some other value. The Inty's color chip treats color information as having exactly half the bandwidth: every set of four timeslices corresponds to a single fat pixel, with 160 pixels per scan line (the same as the Atari 2600). In such a scheme, if the NTSC signal expects an exact division by two AND if the TV's display circuitry is perfectly calibrated to extract color information EXACTLY every other black-and-white pixel, there should be no color bleeding. Any deviation from either - if the NTSC standard specifies something other than an exact division by two or if the TV's color clock is not perfectly synchronized with the black-and-white clock, you'll see color bleeding.

Edited by JohnPCAE
  • Like 3

Share this post


Link to post
Share on other sites

Hi, just bumping this thread with my own choices of palette... after several days of tweaking and experimenting. I know this is not an exact palette, however, it looks very good (what I mean by that is balanced, easy on the eyes) on my TCL Roku TV. With any palette, they'll change with the TV brand, settings, power, lighting in the room...etc. But I wanted to share this just in case anyone was looking to change theirs and needed the actual color codes I used, maybe to start as a base point to tweak their own.

 

While experimenting, I created palettes that matched an actual INTY running on my old 80's 13" TV.. well.. on a 40" LED.. it was unbearable to look at. So I began with JzINTV's original base palette, some of the palettes mthompson posted, then screen shots of videos of CRT's, other INTV images... my own... etc. Until I came up with this that I felt I could look at and not have my eyes burn out... LOL.

 

I used AD&D CM, AD&D ToT, Microsurgeon, Chip Shot Golf, Bomb Squad, Armor Battle, TRON Deadly Discs, and Frog Bog to get a good feel of the colors and see how bright/washed out they look. Also, consider my TV setting will be different than yours... so that will effect the look for sure.

 

If you do decide to use it and tweak it, by all means... post what you come up with. I'm curious to see what others have an what they think.

 

Happy Gaming...

 

JR

 

 

post-21138-0-01498200-1548557913.jpg

Edited by IMBerzerk
  • Like 1

Share this post


Link to post
Share on other sites

Hi, just bumping this thread with my own choices of palette... after several days of tweaking and experimenting. I know this is not an exact palette, however, it looks very good (what I mean by that is balanced, easy on the eyes) on my TCL Roku TV. With any palette, they'll change with the TV brand, settings, power, lighting in the room...etc. But I wanted to share this just in case anyone was looking to change theirs and needed the actual color codes I used, maybe to start as a base point to tweak their own.

 

While experimenting, I created palettes that matched an actual INTY running on my old 80's 13" TV.. well.. on a 40" LED.. it was unbearable to look at. So I began with JzINTV's original base palette, some of the palettes mthompson posted, then screen shots of videos of CRT's, other INTV images... my own... etc. Until I came up with this that I felt I could look at and not have my eyes burn out... LOL.

 

I used AD&D CM, AD&D ToT, Microsurgeon, Chip Shot Golf, Bomb Squad, Armor Battle, TRON Deadly Discs, and Frog Bog to get a good feel of the colors and see how bright/washed out they look. Also, consider my TV setting will be different than yours... so that will effect the look for sure.

 

If you do decide to use it and tweak it, by all means... post what you come up with. I'm curious to see what others have an what they think.

 

Happy Gaming...

 

JR

 

 

Cool. Now try Congo Bongo on that screen and see how it looks on the first game screen. It's tricky balancing the brown, orange, tan, and yellow. I haven't tried yours yet, but a quick eyeball suggests it would look pretty reasonable.

Share this post


Link to post
Share on other sites

This being a pic through my cell phone, it washes out a lot of color, but to my eye, it looks good in person on my TV.

post-21138-0-19113300-1548568372_thumb.jpg

Share this post


Link to post
Share on other sites

This being a pic through my cell phone, it washes out a lot of color, but to my eye, it looks good in person on my TV.

 

That looks really good. The orange is maybe a tad strong, and the brown is a shade dark, but that's about it. I'd chalk it up to camera and lighting differences. Your palette looks really good!

 

These things are notoriously hard to photograph with any sort of accurate color, especially with a cell phone camera. I'm sure a pro photographer could make it work.

 

With my older palette, the orange positively glowed and the tan was way too flat. It was an assault on the eyes.

 

For reference, here's what my Intellivision looks like on that screen in the game. You can see the orange is slightly more muted, and the brown stands out slightly more.

 

post-14113-0-72899000-1548569884_thumb.jpg

Edited by intvnut

Share this post


Link to post
Share on other sites

From my limited experience, I found intellivision looked different on 80s televisions compared to 90s crts or newer televisions. The water in congo bongo should look more blue than pink/purple. Orange should be pale; yellow darker rather than brighter. The default titlescreen should be dark. It's good you're using an 80s tv for reference.

  • Like 1

Share this post


Link to post
Share on other sites

This being a pic through my cell phone, it washes out a lot of color, but to my eye, it looks good in person on my TV.

 

Which one is Cyan in there? I believe it is the one used by the sprites, but the water looks "Light Blue." The actual Light Blue in your palette above looks purplish.

 

-dZ.

Share this post


Link to post
Share on other sites

On my TV, it looks more like Joe's. It's not as blue, but more purple. The trouble with using screenshots from CRTs is that the colors are not true to the actual data... meaning that you are seeing the results of the data after being boosted through an RF xmitter, then a projected on a tube with really 3 guns...Red, Green, and Blue. The Pi3 pushes signal on HDMI to a screen with a bazillion color pixels. If I make a palette based on the RF results, it looks horrendous, and hard to look at.

It might be more to the original look of the game as we saw it, but again, it's not true to the way the game was supposed to look by the actual data.

 

I'll tone down the orange a little, as I think you're right, but other than that, I'm pretty happy as to the results on the set I have the Pi3 hooked up to.

 

The cyan in Congo Bongo is the monkey. The cyan I made shows really well on Frog Bog... while I also color matched the light blue/lavender to match the grey background for TRON Deadly Discs. I don't know that it's supposed to be light blue, when I made it an actual blue shade, it looked terrible in game. Once I moved towards the lavender, it showed a lot better on Armor Battle, Auto Racing and any other games using lavender on green like water.

Share this post


Link to post
Share on other sites

On my TV, it looks more like Joe's. It's not as blue, but more purple.

 

That's how I recall that color.

 

The trouble with using screenshots from CRTs is that the colors are not true to the actual data... meaning that you are seeing the results of the data after being boosted through an RF xmitter, then a projected on a tube with really 3 guns...Red, Green, and Blue.

 

But that's just the thing, right? The palette was designed with that in mind, where the colours blend and bleed in special ways on a CRT. In my opinion, we should strive to emulate that, not perfect technical values. Or better yet, like MAME clients try to do: close-to-perfect emulation with artificial overlay effects.

 

-dZ.

Share this post


Link to post
Share on other sites

I agree with you.

 

That should be the ultimate goal of any emulation. It should be to get as close as possible...however.. it's just not easy to do based on how a modern LED TV works. It will require a lot of filtering and palette adjustment. The end result might not be so pleasing on a large scale as well.

 

In my Retropie build, I have Vice64 set up with CRT filtering and NTSC emulation. Looks really good, but still not as it would on a 1702 monitor. Mostly because of the sheer size of the pixels being played on a 40" screen as compared to a 13" monitor. Same for Stella. I added in old TV backgrounds to make it look like it's on a real CRT based TV. Even with all the filtering, it's still not as the original...BUT...a very good likeness.

 

Testing with a palette based on what the colors project as on a CRT was nothing shy of difficult to look at on an LED. When I hooked up my 13" Sony CRT, the map screen in AD&D was awash in green because the yellow-green was almost neon. The cyan used for the rivers was lost and there was a lot of bleeding. So I created a palette in that likeness for the LED TV and it nearly made my eyes BLEED. Lol. Maybe with a CRT filter over the image it would better, but without it...it was LOUD.

 

I do think this this is a very important aspect if emulation and should be given proper attention. I'm happy to keep playing around with it as others have as well. But until JzIntv has filters built into it...or gets ported to the Retroarch format, I'm going ro keep using a palette that I can stare at without retna burn.

 

JR

Share this post


Link to post
Share on other sites

Also... I found the best game to pull color info from believe it or not was Microsurgeon. It has all 16 colors active on the screen and gives you the best images to color compare on a broad scale, especially in the intestine/abdominal area.

Share this post


Link to post
Share on other sites

Lavender is not a bad way to describe light blue, aka the 14th colour. It's used for the sky in several cartridges so a blueish-lavender would be good.

 

Isn't the background in deadly discs grey, and the other guys colour light-blue/lavender. Isn't the water in armour battle cyan.

Edited by mr_me

Share this post


Link to post
Share on other sites

Yes, and even gray has shades of red, blue, green, purple. It was difficult to get the two colors right. I found a happy medium of neutral gray which made the lavender pop. Before that, any color shade of grey I would loose the lavender, or it was hard to look at with games like ML Baseball and TRON.

Gray, green, yellow-green, brown and purple/maroon were the hardest to pinpoint as they are used as backgrounds, borders and artifacts more than others ON many of the older/original games.

 

JR

Edited by IMBerzerk

Share this post


Link to post
Share on other sites

Isn't the background in deadly discs grey, and the other guys colour light-blue/lavender. Isn't the water in armour battle cyan.

I noticed with Armor Battle it depends on the ROM version. I am using the Sears exec rom, so not sure it effects how the game looks, but I found the "slow" tank Tom version has a green background with lavender water. The "fast tank" rom actually uses the yellow-green background and cyan for rivers. It's a lot louder in the color scheme.

 

Also, my title screen for Shark Shark is brown/Olive drab with black letters, while the Mattel exec should give you the normal cyan title screen with black letters. Toning the cyan was based on Shark Shark and Frog Bog.

Share this post


Link to post
Share on other sites

 

But that's just the thing, right? The palette was designed with that in mind, where the colours blend and bleed in special ways on a CRT. In my opinion, we should strive to emulate that, not perfect technical values. Or better yet, like MAME clients try to do: close-to-perfect emulation with artificial overlay effects.

 

Indeed, I want to emulate the NTSC artifacts and get as close as possible to the original 1980s colors. It requires having accurate I/Q measurements to feed to the NTSC equations. I've literally spent weeks trying to derive the NTSC waveforms, including SPICE simulations. (It's a rathole I climb down every few years.)

 

I think the only way I'm going to get there is to get a digital scope and hook it to the composite output of a VCR tuned to an Intellivision, to get the full AY-3-8915 => RF Mod => RF DeMod transfer function.

 

It doesn't help that the NTSC gamut is larger than the RGB gamut, so even once we have proper NTSC values, we'll need to compress the gamut to maintain the full dynamic range. Compressing the gamut means most colors will look a little too dim, in order to preserve the over-the-top yellow-green and pink colors.

 

EDIT: I should add, the most recent palette in jzIntv was derived with the assistance of TV capture cards. While not perfect, it's much closer to getting the full transfer function, plus some attempt at reasonable gamut compression.

 

 

I noticed with Armor Battle it depends on the ROM version. I am using the Sears exec rom, so not sure it effects how the game looks, but I found the "slow" tank Tom version has a green background with lavender water. The "fast tank" rom actually uses the yellow-green background and cyan for rivers. It's a lot louder in the color scheme.

 

Also, my title screen for Shark Shark is brown/Olive drab with black letters, while the Mattel exec should give you the normal cyan title screen with black letters. Toning the cyan was based on Shark Shark and Frog Bog.

 

The Sears EXEC does not affect the color palette itself. That's defined by the AY-3-8915 color processor + related circuitry.

 

The Shark! Shark! title screen is brown on Sears due to a timing-related bug in the Shark! Shark! title screen code. It directly pokes the STIC border color and color stack registers as part of its title-screen "fixup" code. On the Mattel EXEC, this succeeds. On the Sears EXEC, this fails.

 

This is due to the fact that the Mattel EXEC adds a vertical blank synchronization step, so it can copy the "Copr @ 1984 Mattel" string out of GROM. (That's the exact string. It then overwrites "84" with the correct year.) The Sears EXEC skips this step. This affects the title

 

The title-screen code I wrote for Chad's Intellicart has this same bug.

Edited by intvnut

Share this post


Link to post
Share on other sites

One thing I notice with intellivision on modern displays, even late model crt tvs, is that the default titlescreen looks green. As a kid I would never have described it as green. I might have described it as gold, but olive is a good way to describe it. The pal version looks completely different, so a pal palette would be nice too.

Share this post


Link to post
Share on other sites

One thing I notice with intellivision on modern displays, even late model crt tvs, is that the default titlescreen looks green. As a kid I would never have described it as green. I might have described it as gold, but olive is a good way to describe it. The pal version looks completely different, so a pal palette would be nice too.

 

That's how I remember it. I kind of remember the title screen kind of like a greenish golden colour, not the actual green we get today.

 

-dZ.

Share this post


Link to post
Share on other sites

I call the brown color Olive Drab, because I used to build a ton of airplane models back in the day and Testors sold that color. Lol.

 

My palette is built to display on my TV, so not sure how it will look on any other TV. The title screen color was tweaked to make it as close as I can get to the color of olive drab I remember and what shows on any CRT I hook my real Inty to.

Share this post


Link to post
Share on other sites

Yep, I always considered the color "olive drab" as well.

 

Unfortunately, I got rid of my 1983 Sharp Linytron and my TI-99/4A composite monitor years ago. I did a major CRT purge at some point as I needed space. The 1983 Linytron is what my brother and I played countless games on back in the day. (Well, not quite: We each hand one, and we both had the same model. We played Intellivision on his, and and TI-99/4A on mine.)

 

Since moving to CA, I'm even more cramped for space, and may need to get rid of more things. :(

Share this post


Link to post
Share on other sites

I call the brown color Olive Drab, because I used to build a ton of airplane models back in the day and Testors sold that color. Lol.

 

My palette is built to display on my TV, so not sure how it will look on any other TV. The title screen color was tweaked to make it as close as I can get to the color of olive drab I remember and what shows on any CRT I hook my real Inty to.

 

Yeah, "olive drab" sounds about right.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...