Re: Exact VIC-II colour palette

From: Richard Atkinson (
Date: 2001-03-23 02:13:01

Excuse my lateness; I've only just got around to going through my backlog
of emails after my stay in Texas.

On Mon, 19 Mar 2001, [ISO-8859-1] Marko Mäkelä wrote:

> Last year, I promised to borrow my VIC-II collection to this guy for
> measurements, but for some reasons I never came around to sending it.
> Now it seems that he managed to come up with very good results anyway.

I'll say! His page is *exactly* the sort of thing I've dreamed of for
emulators for years. The results are entirely consistant with what I would
have imagined about the VIC-II design process. Is Philip on the
cbm-hackers mailing list? I'd like to congratulate him on this outstanding

> Now we'll have to convince him to do the same research for the VIC-I and
> the TED.

Personally speaking, I think TED should be next. I'm biased, of course,
but the TED chip is much closer in design philosophy to the VIC-II than
the VIC-I, so I think it would be a logical "extension" of the project. I
expect the luminance values of the TED to be slightly different than those
of the VIC-II; at least that's the conclusion of my visual inspections.
The chrominance values should present an interesting challenge as there
are 14 of them; these must all be different as there is a seperate
luminance control anyway, and they can clearly be seen on the monitor as
distinct over all luminance values. One problem is that the three blues
are *very* close together, but still 3 different colours on every TED I've

> I've noticed that some VIC-20s have very bright white colour, while the
> white background on others looks more grey (C64 colour 15 or 11).  I
> wonder if there are other palette differences.  My main VIC-20 has the
> darker variant of white.

I noticed some curious effects on my old 1802 monitor, with the white and
red colours on a VIC-20 causing some curious waves in the horizontal
raster display, as if the colours were in some way "too bright". This is
less of a problem on the TV sets I use today, as I believe they can cope
with higher input voltage ranges. Out of spec voltage ranges are also a
problem on some of the Atari 8 bit computers.

How many VIC-I variants are there? I've noted 6561Es in my very earliest
VIC-20s (including the ones with PET keyboards), 6561-101s in the later
VIC-20CRs, 6560-101s in NTSC VIC-20CRs and 6560R2s from the batch of chips
Marko distributed. Is there such a thing as a 6560E, maybe inside the
original NTSC VIC-20s? It's curious that the 2 pin American power plug
design is incompatible with the 2 pin European one.


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