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Forums > CSDb Discussions > colodore is the new pepto
2016-12-12 00:26
pepto
Account closed

Registered: Nov 2004
Posts: 35
colodore is the new pepto

Hey guys, I remeasured the video-signals of my VIC-II's and slightly updated my 15 year old attempt at calculating an rgb-clone. While at it, I also measured VIC & TED and made a little website about it, that allows you to adjust brightness, contrast and saturation as you like and then save your own custom palette to a png-file.

http://www.colodore.com


I took extra care to make sure, that the brightness, contrast and saturation sliders behave the same way as my 1084s.

While closely comparing my LCD to the 1084s, I found that making the transparency of scanlines dependent on YUV's Y (so they are less visible for brighter colors) looked a lot more like the real thing. I also noticed that the phase-shift on odd-lines happens for YUV's V only and there's even a name for it in video-lingua: hanover bars.

After implementing this, I'm happy to say that the images on my LCD and 1084s are remarkably close.


I will write a more detailed article about it in January, but seriously need a christmas-break first...

Cheers,
pepto
 
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2016-12-14 15:23
chatGPZ

Registered: Dec 2001
Posts: 11108
the bass/music analogy is a very good one, thanks for coming up with that - must remember.

VICE also phase shifts all colors a bit (4.5 degrees iirc) already :)
2016-12-14 18:00
jailbird

Registered: Dec 2001
Posts: 1576
No offence towards Pepto, as the old palette seemed to me as the golden ratio and it is just fabulous, but this new thingie looks like someone got wild on the color settings of a TV set and set it to the highest value. Or maybe I am just going blind as I get older... Dunno. I get it that it is measured and technically more correct but for some reason it doesn't feel right to me...
2016-12-14 18:13
chatGPZ

Registered: Dec 2001
Posts: 11108
i just hacked it into chameleon.... and what can i say? looking at the VGA and 1701 side by side, they look surprisingly similar now. although the yellow _IS_ SCREAMING YELLOW =D

edit: one thing i noticed - it looks a lot less SCREAMING when you actually configure the output how it should be, ie enable scanlines and everything else.
2016-12-14 19:06
pepto
Account closed

Registered: Nov 2004
Posts: 35
Quote: No offence towards Pepto, as the old palette seemed to me as the golden ratio and it is just fabulous, but this new thingie looks like someone got wild on the color settings of a TV set and set it to the highest value. Or maybe I am just going blind as I get older... Dunno. I get it that it is measured and technically more correct but for some reason it doesn't feel right to me...

Have you tried setting the sliders to something more pepto-like? For example brightness 50, contrast 85, saturation 40 (these are no scientific numbers, I just quickly tried by hand to come up with a pepto-ish look)...

And to get even less scientific... Here's the real 1084s vs. colodore on iPad, photographed with a phone, which has a hard time as brightness of crt vs. lcd-backlight is pretty different for the lense and the original image is also interlaced...



Great image btw., also loved it on the bigscreen at Breakpoint... :)
2016-12-14 20:38
v3to

Registered: Feb 2005
Posts: 150
I am quite pleased of the Colodore colour approach. It is not because of discussing which saturation is right, it is because the control bars lead to an result comparable to my 1084s. Dark blue stays dark blue even with extreme settings.

The PEPTO palette is a similar basis, but if I try to adjust saturation or brightness this tends to unwanted undertones.
2016-12-14 20:41
ilesj

Registered: Jun 2012
Posts: 27
Awesome! Thanks for this - this here addresses many issues around (especially) C64 colors and picture reproduction. And what Groepaz said, the bass analogy is excellent. With these dials both the ‘bass-heads’ and ‘audiophiles’ can set up a palette that looks right.

I have been using the ‘“classic” pepto palette always when working on C64 graphics. Sure, it’s dim and muted, but it represents very well how the colors relate to each other. If colors of a picture looks balanced with ‘pepto’, it looks balanced with real HW. Some of the more saturated and bright palettes around have the colour relations off sometimes in wild proportions. That makes any well crafted picture look like a dog barf and at least my eyes bleed. This is a proper way to crank up brightness and saturation!

And whoever is seeking “one true palette” there’s also the catch that any two random displays won’t look the same. Colour reproduction between different displays just won’t be the same - that would call for colour profiles, calibration etc. So no, those default COLODORE colors may not be anywhere near a good match with 1084 on _your_ display, even though for pepto it is.

And by the way, I think not many laptop displays, for example, can reproduce the spot brightness of a small CRT display, no matter what’s the brightness and contrast setting. Only recently dynamic range has become a thing with HDR standards for UHD TVs.
2016-12-14 21:41
chatGPZ

Registered: Dec 2001
Posts: 11108
Quote:
And by the way, I think not many laptop displays, for example, can reproduce the spot brightness of a small CRT display, no matter what’s the brightness and contrast setting. Only recently dynamic range has become a thing with HDR standards for UHD TVs.

color gamut is another thing - VGA can not reproduce all colors that a PAL-CRT can (and the other way around)
2016-12-14 22:34
Oswald

Registered: Apr 2002
Posts: 5017
I was satisfied with the 'pepto' palette, but if this would make it into vice, in a user friendly way (realtime manipuation) that would be nice.
2016-12-14 22:41
soci

Registered: Sep 2003
Posts: 473
Quoting pepto
Great image btw., also loved it on the bigscreen at Breakpoint... :)


This picture has several errors (on the right) compared to the compo version I know (on the left). The most noticeable is a group of purple pixels near the upper left corner.
2016-12-14 23:05
pepto
Account closed

Registered: Nov 2004
Posts: 35
Quote: Quoting pepto
Great image btw., also loved it on the bigscreen at Breakpoint... :)


This picture has several errors (on the right) compared to the compo version I know (on the left). The most noticeable is a group of purple pixels near the upper left corner.


Interesting, I wonder how that happened... thanks for noticing!

I just ripped a fresh copy - you might have to clear your browser-cache if you don't see it immediately.
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