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+--- Thread: Accurate colours (/thread-549.html)
Accurate colours - Under4Mhz - 12-08-2022
I created a new thread for our discussion on colours.
I noticed from the previous photo that cyan comes up as dark blue. Is that an effect of the vga adapter, or what would be seen on an original system? And does it matter, if nobody has original monitors anymore?
I've written a test app to show the colours on a Microbee. Here is Mame and uBee:
It would be interesting if someone (or Chickman) could run this on a your real system and post a photo?
PS. I can't see the images in this post, they come up as tiny squares.
RE: Accurate colours - MbeeTech - 12-08-2022
>PS. I can't see the images in this post, they come up as tiny squares.
This is being worked on at present.
See this thread for details : https://microbeetechnology.com.au/forum/showthread.php?tid=548
EDIT : now fixed
RE: Accurate colours - Robert - 18-08-2022
Still little squares.
EDIT: now fixed
RE: Accurate colours - MbeeTech - 19-08-2022
Can we please talk about the forum problems with images & attachment download problems
in this thread : https://microbeetechnology.com.au/forum/showthread.php?tid=548
from here on in?
I'd rather have it all in the one place instead of spread across various topics and posts.
Thanks.
RE: Accurate colours - Robert - 19-08-2022
Thanks for the colours program. It seems the colours themselves are largely correct, the issue being the amount of shading of certain ones.
From Chickenman's observations, real colours are somewhere between those of the 2 emulators, would that be correct?
RE: Accurate colours - ChickenMan - 20-08-2022
I'm now home, so will run the program on my real bee tomorrow.
RE: Accurate colours - Ernest - 20-08-2022
Just thought I would throw my hat into the ring on this.
Looking closely at the differences here, it looks to be that the difference lays in the half intensity implementation.
Light Grey and Dark Yellow are the most affected.
The Dark Yellow was an issue even with real hardware depending on the Monitor used, some would show as Dark Yellow others as Brown, I don't recall if the Dark grey was also affected.
The Dark Yellow has something to do with the Green half intensity implementation. I remember reading something about this some time back, but don't recall where.
Ernest
RE: Accurate colours - CheshireNoir - 20-08-2022
I suspect the Dark Yellow as Brown is related to CGA monitors (And some Commodore monitors) implementing it that way.
It was a hack to get more useful colours out of the CGA palette. The Commodore 128 used the same trick.
Good writeup here: https://www.aceinnova.com/en/electronics/cga-and-the-brown-color-in-ibm-5153-color-display/
John
RE: Accurate colours - Robert - 27-08-2022
Finally got to look at this. On an arcade machine (such as pacman), the colour lines go through a resistor network to set the proper intensity of each colour. MAME has generic code to convert resistor values into the final colours.
However, according to the 256tc diagram (I couldn't find one for a colour 128k), the RGBI lines go directly to the "colour port", and it's up to the monitor to do the final mixing. Needless to say, this varies per monitor, and I don't have schematics for them.
I don't know what happened to Chickenman's testing, so I can't really do anything right now. But, should more info turn up, then this can be progressed.
EDIT: I am no longer involved in the MAME project, so this topic may as well be closed, because no fixes will be done.