On Fri, 21 Mar 1997, Roger Merchberger wrote: This is actually similar to the way the Apple ][ does its colour in high resolution modes. I don't remember the exact way it worked, but there were seven visible pixels per byte, and one hidden bit. When that hidden bit was on, pixels in that display byte were orange or blue, and when it was off they were green or purple. A pixel turned on alone had its colour decided by whether it was in an even or odd position, horizontally, and by that hidden bit. If two pixels were turned on side-by-side, the result was a fat white pixel. Of course, if you made the mistake of attempting to plot an orange pixel in a byte with green and purple pixels, the pixels would change colour. And if you POKEd the same value into two bytes that were beside each other, the colours would reverse (green would become purple in the second byte, orange would become blue...). This is how it works on the Laser 3000, too, in HGR and HGR2 modes. But go up to HGR5 and HGR6 modes, and it doesn't work like the Apple anymore. In HGR5 and HGR6 modes, you can plot any colour to any pixel, without affecting the other pixels in that byte. And the basic colours are different: HCOLOR= Apple ][ Laser 3000 0 black1 black 1 green green 2 magenta magenta 3 white1 cyan 4 black2 yellow 5 orange red 6 blue blue 7 white2 white On the Laser 3000, you can do something like this: 10 HGR5 20 FOR X=1 TO 280 STEP 2 30 HCOLOR=X/35 40 HPLOT X,0 TO X,191 50 NEXT X 60 FOR Y=1 TO 7 70 FOR X=0 TO 279 STEP 2 80 HCOLOR=Y 90 HPLOT X,Y*24 TO X,Y*24+23 100 NEXT X,Y On a composite monitor, this gives 64 visually distinct colours. I presume an RGB monitor would show what's really going on, but some of the colours that come out of the "mixing" are really strange, when the two "source" colours are taken into account. I don't really know what the Laser 3000 is doing internally with this... It only seems to use 2 bitplanes for 8 colours (compared to the Apple's use of one bitplane for 6 colours). If I knew how to plug an RGB monitor into this thing (it does have an RGB port, but I don't know the pinouts) I'd be able to see better what it's doing. BTW, in case anyone's interested: In memory, HGR5 occupies $4000-$5FFF and $6000-$7FFF HGR6 occupies $8000-$9FFF and $A000-$BFFF I still don't know where in memory HGR3 and HGR4 are (double hi-res modes with the standard Apple colours). I can't seem to address them directly with POKE. Must be hiding up there in those other memory pages. At least the Apple was consistent with the colours, so I guess it's not just artifacting called a 'feature' (it really is a feature). That's cool, BTW. I think I'll drag my Laser 3000 out as soon as I have time and see if its reset can swap the colour sets. If so, I can use the same trick the Color Computer used for my own software. Yup, I remember this on the Apple, using the monochrome monitor. :) Doug Spence ds_spenc(a)alcor.concordia.ca