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GT64/GT65 colour palette in WinAPE

Started by tastefulmrship, 11:08, 20 November 11

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tastefulmrship

Hola tout le monde!

I'm looking into an 'obsession project' that requires me to use the grey-scale abilities of the GT-64/GT-65 monitors, but because I use WinAPE exclusively I have a little problem; grey-scaling in WinAPE is easy, so long as you know the RGB values of the source image. However, this produces interesting colours when the 'Linear Palette' option is set in the Display Settings, but produces the correct colours when it is not set.
What I need to know is which of these 'colour' scales is correct to real-hardware? 'Linear Palette' on or off.

Here are two pictures with the complete grey-scale in both 'palette modes'. Can someone tell me which is closest to reality?
(obviously, I'd prefer the 'NoLinearPalette' to be right!)

Muchos thankos!

Morn

So, how are we supposed to test this on a real machine? Couldn't you provide a BASIC program that draws this INK pattern on the screen?

tastefulmrship

Quote from: Morn on 15:43, 20 November 11
So, how are we supposed to test this on a real machine? Couldn't you provide a BASIC program that draws this INK pattern on the screen?

Well, if you cycle the first 15 colours;

5 REM BASIC PROGRAM #1
10 MODE 0
20 FOR n=1 to 15
30 INK n,n
40 PEN n
50 PRINT CHR$(143);
60 NEXT n
70 END

Does it look like a proper gradient? Or is INK #9 actually darker than INK #8?

(... and yes, ignore lines 5 and 70!)

Morn

Quote from: tastefulmrship on 18:13, 20 November 11

Does it look like a proper gradient? Or is INK #9 actually darker than INK #8?

They're almost the same brightness, but #9 is slightly brighter. So it does look like a pretty smooth gradient to me.

I've never really noticed this property of the first 16 INKs on the GT65 before. Fascinating!  :)

MaV

#4
Quote from: tastefulmrship on 18:13, 20 November 11
Does it look like a proper gradient? Or is INK #9 actually darker than INK #8?

Looks like a nonlinear palette to me. (GT65 + CPC464/6128)

Take a look at the Climax G demo for some juicy pictures that exploit this fact (green screen only).
http://sylvestre.cpcscene.com/demo_productions.html
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tastefulmrship

#5
Quote from: Morn on 18:34, 20 November 11
They're almost the same brightness, but #9 is slightly brighter. So it does look like a pretty smooth gradient to me.
I've never really noticed this property of the first 16 INKs on the GT65 before. Fascinating!  :)

Quote from: MaV on 18:36, 20 November 11
Looks like a nonlinear palette to me. (GT65 + CPC464/6128)

So I'll make sure that LINEAR PALETTE is not ticked in the Display Options.

Thank you muchly, sirs.
- JTMS...


EDIT: In the same vein as CLIMAXG, here's Kaley & Jim in WinAPE-esque grey-scale in overscan!

TotO

Quote from: tastefulmrship on 11:08, 20 November 11Here are two pictures with the complete grey-scale in both 'palette modes'. Can someone tell me which is closest to reality?
If fact, both gradians are done by displaying the same inks... So, it's just a "display" problem and don't have any incidence on your code?

On pictures, linear fail... Really strange. :D
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

tastefulmrship

#7
Quote from: TotO on 21:12, 20 November 11
If fact, both gradians are done by displaying the same inks... So, it's just a "display" problem and don't have any incidence on your code?
On pictures, linear fail... Really strange. :D
The problem stems from knowing which INK represents the real 'shade' on real hardware... as it were! If the LINEAR palette is how real looks, then I need to change all my palettes to match, otherwise they're fine.
And it will change the code, as I'll have to move the fade-in INKs to a LINEAR set (0, 1, 2, 3, 4, 5, 6, 7, 9, 8, 11, 10, etc) to look like a proper fade in. Presently it's just 0-26 and then 26-0 to fade out.

My grey-scale images look terrible in LINEAR, yet fine without.
It's strange alright!

TotO

The CPC palette is like I quoted some posts before. (code)
It's a proportional dark to light steps. (first Bleu, then Green, finaly Red)
So, you may try to increase by changing the RGB order to see if you get better ???
"You make one mistake in your life and the internet will never let you live it down" (Keith Goodyer)

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