Old HAM pictures from Digiview I think

[amigaksi]

>by Rowbeartoe on 2008/7/28 4:04:49

>I use GBMREF on the PC to convert to Amiga Formats. XNVIEW >displays my Amiga pictures that I can then save to BMP or >whatever. I still have to play with my Amiga 500 to file share with the PC (via null modem) so I can start converting SHAM pictures and saving them to the PC using GBMREF. I have to learn how to do that, and I think I found some places that explains how- but right now I just don't have that kind of time. My interest right now is in finding those old pictures. I want to convert them to the Atari ST using Photochrome and other various programs including Spectrum 512 (hopefully with better results). To bad I couldn't get the orginal photographs in 24bit from those NewTek guys. =(

Do you have a utility that uses custom copper lists to convert to Amiga formats or just using the stock Amiga modes?  I still have the Spectrum 512 images you sent me, but I have not had the time to write a custom copper list generator.  The algorithm was to use a 32-color mode and change registers within HBI and mid-screen to simulate at least the color register modifications of the Spectrum 512 so any image on Atari ST can be shown on Amiga losslessly.  Do you happen to know at which color clocks the Spectrum 512 modifies the palette?  I don't have that software.

>Thanks for all your help guys.

Is that Spectrum 512 limited to 320*200 or does it also do mid-screen changes in 640*200 mode?

[amigaksi]

>I presume you mean ADFView?

Does that handle the hard files without requiring manual editing of the Mountfile?

[amigaksi]

>Spectrum 512 divides each scan line 3 times for 48 colors per scan line(actually 42 if you want to use and edit with the paint program, 45 if you don't use the paint program and 48 if you use one of the photochrome modes). HAM6 can best Spectrum 512 in some ways because you can have 320 colors on a scan line. But HAM6 is limited because after those 16 "free" colors you can only modifify one of the 3 RGB values from a previous color causing unessary colors. Spectrum 512 is limited to 320x200. No interlacing.

I was talking about just 32-color mode on amiga not HAM6.  In 32-color mode with a custom copper list, I was able to do 61 free colors per scan line.  Using a 7.16Mhz Amiga, there's enough time in the HBI to modify 14 color registers, and 30 registers during visible portion of screen (in 320*x mode).  Now if you partition the 32 colors into 14:17:1 where the first partition is colors that change during HBI, 17 that are staying the same from scanline i to i+1 (using delta-modulation where more common colors take on those indices), and take the 32nd color and repeatedly change it 30 times during visible portion of the screen you get: 14+17+30 = 61 free colors per scan line more than Spectrum 512.  And I have not involved the Amiga CPU either.

>Photochrome looks amazing (bests VGA in many ways) but wasn't available until early 90's (spectrum 512 came out in 1987!). Photochrome interlaces two pictures and color mixes giving you 96 colors per scan line and a 4,096 color palette (for standard ST). Flicker is at a minimum for most cases and is similar to looking at interlaced pictures on the Amiga.

Those interlaced colors have to be distinguished from the REAL colors as the interlaced colors have half the refresh rate.