Asking for trouble using color $2D?

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gravelstudios
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Asking for trouble using color $2D?

Post by gravelstudios » Wed Nov 20, 2019 4:50 pm

In my current project, I'm using color $2D quite a bit. I find that I like it better for dark gray than $00, which I find too light most of the time. I know that the RGB PPU from the Playchoice machine will treat this color (as well as all $XD palette entries) as black. Is this going to be a problem for a large number of players? what do you think is the percentage of people with an RGB modded NES on which this color will not display properly?

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Re: Asking for trouble using color $2D?

Post by lidnariq » Wed Nov 20, 2019 6:30 pm

Color $2D should be fine. Not very many total 2C03s / 2C05s were made, and although a higher percentage of them (in the form of Vs. Systems, Playchoice-10s, Famicom TVs and Titlers) have probably made it to the current day than NESes and Famicoms, I think it's still going to be a small percentage.

I'd say that the loss of the color emphasis bits is a much bigger hit than the loss of color $2D ... and I'd still say it's not worth worrying about.

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Dwedit
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Re: Asking for trouble using color $2D?

Post by Dwedit » Thu Nov 21, 2019 3:41 pm

Just don't do naive fades that subtract $10 from the color value, and you won't end up writing $0D (blacker than black) to the palette.
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gravelstudios
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Re: Asking for trouble using color $2D?

Post by gravelstudios » Fri Nov 22, 2019 3:56 am

Dwedit wrote:
Thu Nov 21, 2019 3:41 pm
Just don't do naive fades that subtract $10 from the color value, and you won't end up writing $0D (blacker than black) to the palette.
My fade-out routine checks for $1D and $2D and changes them to $0F, so that's not an issue.

Thanks guys. I think I'll keep using the $XD entries and not worry about it.

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Re: Asking for trouble using color $2D?

Post by Tag365 » Wed Feb 26, 2020 1:00 am

Dwedit wrote:
Thu Nov 21, 2019 3:41 pm
Just don't do naive fades that subtract $10 from the color value, and you won't end up writing $0D (blacker than black) to the palette.
What happens if you use the blacker than black color $0D? Does something bad happen to the system?

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Re: Asking for trouble using color $2D?

Post by lidnariq » Wed Feb 26, 2020 1:15 am

nesdevwiki:Color $0D games wrote: Because the signal created by $0D is outside the specifications for the video signal, there is a lot of variation in how display devices handle it. Here are some possible effects that may be seen when using $0D:
  • $0D appears the same black as the other black colors (e.g. $0F).
  • $0D appears slightly darker than other blacks.
  • The device renormalizes the range when $0D appears, slightly brightening all other colours while it is onscreen.
  • Wobbly or distorted image from loss of horizontal blanking stability.
  • Total loss of picture.

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Re: Asking for trouble using color $2D?

Post by calima » Wed Feb 26, 2020 1:23 am

Your TV may go "no signal", or give a glitchy picture. edit: ninja'd.

Tag365
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Re: Asking for trouble using color $2D?

Post by Tag365 » Wed Feb 26, 2020 12:14 pm

Are there other colors that cause similar issues? I read that some of the colors used by the NES are out of the normal color gamut, and as a result are not rendered consistently on all screens. Apparently this is what caused emulators of NES games to use palettes different from one another.

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rainwarrior
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Re: Asking for trouble using color $2D?

Post by rainwarrior » Wed Feb 26, 2020 2:22 pm

No, only $0D is a problem for loss of picture.

$2D and $3D are only a problem for sharp titler, old RGB mods using specific arcade PPUs, etc. which don't have that colour, and/or a problem with emulators with bad default palettes like FCEUX that make them too close to the other greys.

The failure of emulators to agree on a specific palette is not really an issue with the NES. Colour representation is just fairly subjective, and LCD != CRT and RGB != YUV, so anything you choose is a compromise. The consequences of this is a lot more subtle. Nothing is really "broken" by it, and everybody gets it "close enough" more or less.

As for the $D column, not a lot of NES games actually used it. If someone has a bad $2D in their palette they could easily be unaware of it. The reasons above might be enough justification to avoid it, depending on your perspective, but it will work fine on normal NES and Famicom systems.

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Re: Asking for trouble using color $2D?

Post by lidnariq » Wed Feb 26, 2020 2:34 pm

Also, NTSC has had at least three different Official Rules for how to decode it.

You might find Drag's palette generator interesting.

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