Doing pictures using Super IRG 2 and other ICE modes.

[Synthpopalooza]

One more pic, again from Space Ace ...

 

The Atari ST original:

 

 

The PCIN pic:

 

 

 

This time I have managed to get the colors very close to the ST original. This required a slight adjustment of the color registers, as it seems G2F and AIS work off the PAL palette which is inaccurate. Also, the grey bit in the sky at the top, required adjustment of register 705 to a dark green, which when interfaced with the orange in reg. 711, makes a grey. To make greys, you blend colors from opposite sides of the color wheel.

 

Also, the blue part of the picture behind Ace flickers. This comes from blending white (710) with mid blue (register 712b, under graphics 10). It may require opening the fonts in ICE and trying a different color.

 

ATR is here:

 

spsh.atr

Edited May 9, 2012 by Synthpopalooza

[Synthpopalooza]

Another PCIN pic, this time a digitised photo ...

 

Original:

 

 

PCIN pic:

 

 

I have improved the dithering algorithm, it will now dither inverse characters correctly using PF3.

 

ATR is here:

 

clown.atr

 

Run D:CLOWN.TUR

 

Next step: Try to render these in low-res PCIN using Antic 5 (96 scanlines). This will require a reorganzation of the Gr. 10 palette.

[Synthpopalooza]

I have successfully rendered the clown picture in low-resolution:

 

 

I call this display mode PCIN IRG. It is like PCIN except that this time the display uses ANTIC 5 (Graphics 13) mixed with Graphics 10, instead of Antic 4.

 

Differences in this display mode are, that since you can't use Antic 2, you have to use the graphics 10 palette under Antic 5. You still get all 9 Graphics 10 colors, but the paletting is different. Basically, we are only concerned with color combinations 5 through 11 in this mode, and they are laid out as follows:

 

Normal Characters: Inverse characters:

 

5 - COLP0 (704) COLP0 (704)

6 - COLP1 (705) COLP1 (705)

7 - COLP2 (706) COLP3 (707)

8 - COLBAK (712) COLBAK (712)

9 - COLPF0 (708) COLPF0 (708)

10 - COLPF1 (709) COLPF1 (709)

11 - COLPF2 (710) COLPF3 (711)

 

Notice that, in bold, color combinations 7 and 11 change when the character is in inverse ... specifically, COLP2 is replaced with COLP3 and COLPF2 is replaced with COLPF3. This is analogous to the Antic 4/5 color layout, where COLPF3 replaced PF2 when in inverse. This means of course that you cannot have P3 and PF3 in the same character cell with P2 or PF2.

 

With this limitation, your color resolution in PCIN IRG is slightly reduced from 34 colors to somewhere about 32.

 

The fonts in this picture were converted from normal Graphics 10 fonts, using an algorithm which converts the colors into their appropriate Antic 5 equivalents, and does substitutions with the next nearest color if there are any PF2/P2 and PF3/P3 conflicts. Where PF0-PF3 mix across modes, the pixels have also been dithered in a checkerboard pattern to reduce flicker.

 

So, basically, you now have a display mode which can show 32 colors at Graphics 7 resolution. You could theoretically use this as a bitmap mode, except that you would be POKEing into the character font memory instead of the screen memory to plot pixels, only using the screen memory to inverse a character anywhere you wanted to use COLP3 or COLPF3. The coordinate system would be different as well, but theoretically, softsprite routines could also be written for this display mode as well ... imagine using this mode for games like Space Harrier.

 

The ATR is attached. Run "D:CLOWNLO.TUR"...

 

Warning: This demo will only run accurately on a real Atari, or on Altirra versions 2.0 and up. There is an issue where color #8 (COLBAK) does not display correctly in this mode under most emulators (COLPF0 at 708 is shown instead). This bug was addressed and fixed with Altirra 2.0. In addition, earlier versions of Atari800Win will not display correctly the lowercase and control characters in this mode.

 

Next step: Doing CIN (Gr. 13+11) and MIN (Gr. 13+9) pictures in this resolution, followed by GTIA modes in this resolution (including HIP ... which should allow 35 shades monochrome in this resolution).

 

clownlo.atr

Edited May 13, 2012 by Synthpopalooza

[Synthpopalooza]

A pic using MIN mode. Original:

 

 

MIN pic:

 

 

MIN is a combination of Antic 4 (Graphics 12) with Graphics 9. When used as a monochrome mode, you get somewhere about 25 usable shades of grey at 160 pixel resolution. While this is less than what you get in HIP mode (Gr.9 + Gr.10 and 31 shades), MIN has three advantages:

 

The image is sharper than in HIP modes, because the pixel layout is 2 Gr. 12 pixels blending with one Gr. 9 pixels, and no artifacts on either end.

 

You have the possibility of using PMG overlays with blending (which you cannot do in HIP mode), and thereby adding colors to your image (5 chroma x 25 luma, or 125 colors).

 

You can do a checkerboard dithering pattern (like in PCIN) in some areas of the picture. How this works in MIN is, the values stored in PF0-PF3 and the background color, are interleaved with the corresponding colors as they occur in the Graphics 9 picture. The result is a checkerboard pattern, which when blended makes a solid color, and less flicker.

 

Here is the .ATR. Run D:EYE.TUR ... next experiment will be to try to render this in lo-res ANTIC 5 (like the clown picture).

 

eye.atr

[+Stephen]

That eye picture is awesome! It appears that the 25 shades of grey are freely usable?

[+Stephen]

Looks great on the real machine. Bonus of my scan doubler, is no flicker on these 30Hz modes.

[Synthpopalooza]

That eye picture is awesome! It appears that the 25 shades of grey are freely usable?

 

There is a limitation ... as the effect blends two Antic 4 pixels with one Graphics 9 pixel, 2 neighboring pixels cannot vary by more than about 2 steps. In addition, due to the limitations of PF3-PF2 in Antic 4, those two base shades cannot be in the same character cell. In this instance, shade values 4 and 8 under Antic 4 are used for PF2 and PF3.

 

The picture was generated by using G2F to make two sets of font files, one for Antic 4 and one for Graphics 9, and these are blended together, along with some dithering where common shades across both modes are evened out to reduce flicker. It is possible a better rendering algorithm could be made, that would smooth out the picture even more and reduce the flicker even further.

[Synthpopalooza]

The eye picture has now been rendered in MIN IRG. Three screenshots:

 

 

MIN IRG is a low-res version of the Super MIN mode shown in the previous post. The pixel resolution is the same as in Graphics 7, and has a slightly reduced shade usage, somewhere from 19-20 shades.

 

The main difference in this mode, from Super MIN, is the reduced number of shades. The reason for this is that it is required to use ANTIC 5 with the GTIA set to mode 9, as one of the base modes. Unlike setting the GTIA in Antic 2, using mode 9 under ANTIC 5 (a hardware mode I call Graphics 13.9) reduces the number of shades you can use. This is because ANTIC orders the colors differently. This color table shows how everything works:

 

Normal Inverse

0 - Color 0 Color 0

1 - Color 0 Color 0

2 - Color 1 Color 1

3 - Color 2 Color 3

4 - Color 0 Color 0

5 - Color 0 Color 0

6 - Color 1 Color 1

7 - Color 2 Color 3

8 - Color 4 Color 4

9 - Color 4 Color 4

10 - Color 5 Color 5

11 - Color 6 Color 7

12 - Color 8 Color 12

13 - Color 8 Color 12

14 - Color 9 Color 13

15 - Color 10 Color 15

 

You will notice that Graphics 9 colors 11 and 14 are unavailable here, which reduces your color resolution slightly. Each character cell is limited to 9-level shading, and the bit patterns shown in bold indicate where differing shades are available in inverse, Basically, the 4 brightest shades can only be used in inverse characters, along with shades 3 and 7, while the mid level greys 8 through 10 can only be used in normal (atascii<128) characters.

 

This requires a slightly different algorithm for converting greyscale pictures ... in the demos below, I simply converted the character to the nearest level grey based on the attributes (normal or inverse) of the corresponding Antic 4 character. It is possible that a better algorithm can be done, using screen flipping (i.e. mixing normal and inverse characters in the same character cell). It is also possible to rearrange the color paletting in ANTIC 5 so that PF3 is the brightest level shade, and PF2 the next shade down, so that the color palette better matches with Graphics 13.9.

 

The limitations therefore are: You cannot have mid level greys 8-10 in the same character cell as high level greys 12-15, and also, in Antic 5, the shade for PF3 cannot be in the same character cell as PF2.

 

It is possible also, that this mode could be used as a bitmap mode, with POKEs being made to the character font memory to plot pixels ... and perhaps a softsprite routine could be done as well. This is potentially a good mode to use for games similar to Zybex, R-Type, or Xenon, which require intricate color shading. Also, it is possible to use PM overlays in this mode as well to introduce other color shading as well.

 

An ATR is attached. Run D:EYEIRG1.TUR, D:EYEIRG2.TUR, and D:EYEIRG3.TUR

 

Warning: These demos will only run on a real Atari, or on Altirra version 2.0 or greater. Like the PCIN IRG modes, other emulators have difficulty handing the MIN IRG mode, the higher level ATASCII characters will not display correctly.

 

eyeirg.atr

Edited May 21, 2012 by Synthpopalooza

[Synthpopalooza]

MIN can also be used to good effect for sepia tone pictures.

 

The original:

 

 

MIN pic:

 

 

It is not always necessary to use monochrome values for PF0-PF3 in this mode. With some variations in chroma, some very subtle and warm gradients can be had in this mode. In this case, the PF settings range from green-yellow to red-orange.

 

ATR below. Run D:ROSE.TUR

 

rose.atr

Edited May 22, 2012 by Synthpopalooza

[Synthpopalooza]

A comparison between MIN and HIP modes:

 

Original picture:

 

 

MIN picture:

 

 

HIP 0 picture:

 

 

You can see easily the differences. HIP mode offers more colors than MIN (144 vs 80 in MIN), and the colors are more subtle. The tradeoff is the image is a little more blurry than the MIN image. The HIP image was done in text mode, but the method is similar to bitmap RIP pictures. The color registers in MIN were given a subtle gradient, from dark green through to bright yellow and orange.

 

ATR's below. On NIGHT.ATR run D:NIGHT.TUR, and on NIGHT-HIP.ATR run D:NHIP.TUR ... the ICE files on these can also be loaded in the ICE CIN and ICE GTIA font editors, respectively.

 

night.atr

night-hip.atr

[emkay]

This is what RastaConcverter does (it's still working on it)....

 

 

 

Imagine Rastaconverter or G2F graphics in interlace ....

 

btw. Why do you resize the pictures ?

Edited May 31, 2012 by emkay

[ilmenit]

Some other pics from this thread by RastaConverter:

Mountain1.xex

SepiaFlower.xex

SpaceAce1.xex

SpaceAceTitle.xex

StoneAge.xex

night.xex

[Synthpopalooza]

I haven't yet been able to render these in normal mode yet ... the VBI/DLI routine I am using has limitations, in that I can only change 8 registers per VBI ... the pictures use narrow mode so that I can use fewer fonts (there is a DLI font change every 4 lines, 5 double font sets used for narrow mode pictures). MIN pictures require no color register changes, so they can cover the entire screen this way, but with other modes the screen render comes up 4 character lines short.

 

My next experiment will be to try to render these in 40 column normal mode, it will likely require either using extended memory for bankswitching (switching 8 font sets at once) or possibly a new character set DLI routine and DLI table switch. Optimizing the characters would also save on memory and increase the real estate on the screen. Currently it takes about 10K of font memory plus 768 bytes to do a narrow mode screen ... 1572 bytes if you do screen flipping (which is needed for modes which use Antic 4 on both ends, like Super IRG 2). In normal mode, it becomes 16k for font memory plus 968 bytes screen memory.

 

These pictures were done using G2F ... by exporting character sets from each screen, plus an inverse screen map for any ANTIC 4 font sets. Atari Interlace Studio was also used for the PCIN and HIP pictures, by rendering a Graphics 10 bitmap and loading that into G2F.

 

It would be nice to have G2F render these ICE mode pics ... maybe also, have support for these modes in AIS as well. Being able to optimise these double fonts like in G2F would really cut down on the memory needed,

Edited May 31, 2012 by Synthpopalooza

[Synthpopalooza]

A step further:

 

Original pic (from the Blade Runner movie poster):

 

 

PCIN pic:

 

 

I have now gotten the PCIN picture to display all 24 lines on-screen. The next step will be a full 40 column display. This picture also seems to flicker alot less than other pictures, even though there is very little dithering ... very few areas of the picture exist where PF0-PF3 overlap, except for some solid color fields formed by the same playfield color in both Gr. 12 and Gr. 10 pictures, these do not flicker at all.

 

ATR: Run D:BRUN.TUR

 

brun.atr

[Synthpopalooza]

New experiments ... this time, in a mode I have named Super 10+.

 

Original pictures:

 

 

Super 10+ pictures:

 

 

 

This is probably the most complex of the ICE modes. 8 color register changes, along with 8 character font changes, produce a screen at Graphics 10 resolution, at 81 colors. This mode would be terrific for photos and landscapes. Although I have used character mode for this, the same idea would easily apply in bitmap mode as well.

 

The screens were generated using Atari Interlace Studio (to generate the Gr. 10 bitmaps) then taken into G2F to make the font files. The trickiest part is selecting the interlace colors from AIS, care must be taken so that the colors will blend well without flicker yet still retain the color depth of the original picture. It is possible through editing the pictures on the pixel level, that additional color combinations can be introduced.

 

I have now also gotten these pictures to display 24 lines at 40 columns, after some hacking of the VBI routine.

 

ATR's are below. On LANDSCAPE.ATR run D:LANDSCAP.TUR and on BRAZIL.ATR run D:BRAZIL.TUR

 

landscape.atr

brazil.atr

[Synthpopalooza]

Back to PCIN mode again, with a converted Commodore 64 picture.

 

Original C-64 picture:

 

 

PCIN picture:

 

 

PCIN is excellent for displaying 16-color commodore palette pictures. I have managed to get full screen display at 40 columns, but at a price. PCIN requires that the Graphics 12 screen be shifted one pixel (or color clock) to the right. The Graphics 10 pixels are one color clock off in relation to the display (this effect is used in the HIP mode) ... it seems however, that the custom display list (which uses HSCROL and LMS instructions, plus 8 DLI changes) causes lines to flicker in the display, as shown on the D:PILGRIM2.TUR program on this ATR

 

Unless this can be fixed, the only other method is to shift the picture to the right in G2F before rendering, which can itself introduce PF2-PF3 artifacts in inverse characters. It also makes the anti-flicker dithering more difficult.

 

Run D:PILGRIMS.TUR (and D:PILGRIM2.TUR) on the ATR below.

 

pilgrims.atr

[Synthpopalooza]

Another picture, this time in DIN mode.

 

Original picture (off the Duran Duran album "Rio")

 

 

DIN picture

 

 

DIN is a combination of Graphics 0 and Graphics 12 (ANTIC 2 and ANTIC 4) ... you physically get 5 colors at 2 luminances (10 colors) at 320 pixel resolution. The real trick here is, by taking advantage of Graphics 0 artifacting, your color resolution is effectively increased to 20 colors in this mode. The drawback is, artifacting is very unpredictable, giving different results on differing machines. The above picture was rendered on Altirra using NTSC artifacting. I would be interested in seeing what results are gotten on the real Atari.

 

The pictures were loaded into G2F ... the Graphics 0 render was first posterized using The Gimp, to reduce the colors. The artifact colors (green on the squares, and purple on the woman's necklace) were hand drawn into G2F, a very painstaking task. Also, color register 709 under ANTIC 4 was altered to a bright yellow-orange, which when mixed with the 709 white luminance in Graphics 0 makes for a very appealing off-white flesh tone similar to the Patrick Nagel original.

 

The ATR is below. Run "D:RIO.TUR"

 

rio.atr

[Synthpopalooza]

Another picture, this time in a new mode I have named PCIN+

 

Original picture (The Simpsons):

 

 

PCIN+ picture:

 

 

PCIN+ is a modification of the PCIN (Graphics 12 + Graphics 10) mode. The chief difference in PCIN+ is that, in addition to the COLBAK, GTIA, and display list shifts which create this mode, the playfield registers PF0-PF3 also get shifted each VBLANK. This results in an increase in color resolution, to 45 colors in hi-res mode, and about 42 colors if you use ANTIC 5 low-resolution.

 

So the advantage is you get better color accuracy with your renders, but the disadvantage is, since PF0-PF3 are no longer shared between Graphics 12 and Graphics 10, the anti-flicker PCIN checkerboard dithering of these colors is no longer possible. Extra care must be taken to insure that flicker is kept to a minimum. So whereas PCIN is good for pictures that rely on 16-34 colors, PCIN+ works better for pictures with a higher color volume.

 

Again the two parts of the display (Graphics 12 and Graphics 10) were rendered in G2F and AIS. Here, however, you don't need to keep the PF values the same in both modes. You want a variety of colors, but also two source images which look distinguishable, as these will blend better. I also had to slightly adjust the brightness of the purple background (register 707) in Graphics 10 so it wouldn't cause the display to flicker as much when overlaid atop COLBAK (712 - white) in Graphics 12.

 

There is one other difficulty which is still plaguing my PCIN renders: The striping which occurs in the picture, due to the extra memory cycles needed for the Graphics 12 display list which uses LMS+HSCROL on every line of the display. This is needed to keep the display lined up properly. A new DLI routine may fix this ... or shifting the Gr. 12 bitmap right by one color clock in G2F will solve this as well, as we don't have to worry about pixel dithering in PCIN+.

 

I plan on adding this display mode to my ICE CIN font editor, soon.

 

ATR is below. Run "D:SIMPSONS.TUR". A real Atari, or Altirra set for frame blending, works best here.

 

simpsons.atr

[Synthpopalooza]

Today's example is in a mode I call Super 9

 

Original picture:

 

 

Super 9 picture:

 

 

Super 9 is a very interesting display mode. Like the name indicates, it is a modification of Graphics 9 in text mode, but with the character fonts and COLBAK (712) being altered every VBLANK. You get a resultant 256 duo-tone shades in this mode, though to reduce flicker you will only want to use color combinations within 5 luma steps of each other.

 

To get best effect with this, you want to choose photographic quality pictures which have 2 color hues to them, like the blue-green landscape used above. Two renders are made using G2F under Graphics 9, one of them has the "greyscale" box ticked while the other does not. You also want to alter COLBAK (712) so it cycles between values on opposite sides of the color wheel. In this case, the values I used are 32 and 128, which on an NTSC Atari correspond to orange and blue. The orange gets used for the non-greyscale Graphics 9 render, while the blue setting is used for the Graphics 9 render with "greyscale" ticked. This creates a picture with a highlighted blue background, and a slightly off-green-grey landscape.

 

I used text mode for this, but you can also do an interlaced Graphics 9 screen where the screen lines and COLBAK are altered every scanline, as indicated above. Also, when doing your own pictures, you may want to try these values for your picture and see which looks best:

 

Orange - Blue: 32 - 128

Red - Cyan: 40 - 160

Magenta - Green 60 - 192

 

These are approximate values, but the idea is to blend colors on opposite sides of the color wheel, one of the colors chosen will be one of the dominant colors in your original image.

 

The Super 9 screenshot was done in Altirra with Frame Blending on. On a real Atari you will get flicker, although it looks better in NTSC. The colors may look slightly different.

 

ATR is attached, run "D:ALASKAS9.TUR". I am also including the G2F files for both renders, so you can more easily see how I did it. The .FNT files on the ATR disk are each 8 screen fonts rendered from G2F using the "Save All Data" function.

 

alaska-super 9.atr

alaska-g2f.zip

Edited June 20, 2012 by Synthpopalooza

[+Stephen]

Today's example is in a mode I call Super 9

 

Original picture:

 

 

Super 9 picture:

 

 

That looks great, especially on the real machine!

[Synthpopalooza]

I've whipped up a couple of more examples, from pictures eariler in the thread ... the brazil landscape and the orange landscape:

 

 

This time, I used some slightly different color settings. For the orange landscape picture, I used COLBAK settings of 32 (orange) and 48 (red), as this picture is very orange intensive. In this one, the Graphics 9 color render is actually darker than the monochrome render (which I used orange for), so it does flicker a bit more, but gives off a lot of subtle gradients varying between red and yellow.

 

On the Brazil picture, I decided to do opposite ends of the color wheel again, only this time I used 32 (orange) blended with 144 (Atari default blue) ... this results in a color blend that very closely matches the original picture. For PAL machines, these colors will need to be modified slightly.

 

I noticed a quirk with Altirra in Super 9 ... the color mix is different depending on whether Frame Blending is turned on, or off ... the off setting results in flicker, but I suspect the color mix here more closely resembles what you would get on a real NTSC Atari, whereas Frame Blending tends to make the colors a bit more washed out.

 

Here is another interesting tidbit: You can potentially use PMG's on top of the graphics here as well, using PRIOR 0 to enable Graphics 9 blending. Combining this with color register flips of 704 through 707 (and 711 if you use 5th player) and changing player widths can seriously increase the color resolution in this mode.

 

On the brazil ATR, run D:BRAZILS9.TUR

On the landscape ATR run D:LANDSCS9.TUR

 

And again, I am putting the source G2F's into a zip here as well.

 

brazil super 9.atr

landscape super 9.atr

super 9 g2f files.zip

Edited June 20, 2012 by Synthpopalooza

[+MrFish]

On the brazil ATR, run D:BRAZILS9.TUR

On the landscape ATR run D:LANDSCS9.TUR

 

And again, I am putting the source G2F's into a zip here as well.

 

 

landscape super 9.atr

super 9 g2f files.zip

 

I wasn't able to open up the Brazil pic until I changed line 1019 to look on the "D:" drive. It's looking for the fonts on the "H:" drive in the original file.

 

 

Nice picture. I like the colors you're using in that one.

[Synthpopalooza]

Thanks! It really is a matter of trial and error, you want to pick colors which will work well together and bring out the hues of the original picture. The difficulty arises in that the emulator gives such differing results to the real machine, you really have to do a lot of guessing.

 

I couldn't resist ... two more pictures.

 

Originals:

 

 

Super 9's:

 

 

One last tip: On the real Atari, turn down your monitor's brightness until the border turns near black, and the colors stand out more in the pictures, much like in Jeff Potter's COLRVIEW (an old viewer which does a Graphics 9 triple RGB interlace)

 

The ATR's: PLANE.TUR and LAKES9.TUR respectively

 

plane super 9.atr

purple lake super 9.atr

Edited June 20, 2012 by Synthpopalooza

[Synthpopalooza]

More Super 9's ...

 

The originals:

 

 

The Super 9's:

 

 

Run TITANS9.TUR, SPACES9.TUR, CONQUEST.TUR, or GENESIS.TUR on the appropriate ATR ... and again, turn down the brightness and turn up the contrast on your monitor.

 

My next project will be to develop a custom file format (.IFP or Ice Font Picture), converter, and viewer, Objective is to get these pictures to display and viewfrom a single file, and to write a converter which will read .FNT, .SCR, and color palette info from G2F and automatically turn it into .IFP ... this format will cover all the ICE modes, saving the font data, screen data, graphics mode info and color palette info.

 

titan -super 9.atr

conquest - super 9.atr

genesis - super 9.atr

space -super 9.atr

Edited June 21, 2012 by Synthpopalooza

[Synthpopalooza]

I'll give a tutorial on how to do your own Super 9 pics, as these are real easy to do.

 

You need G2F, and also the viewer program I have attached to the ATR in this post. A good photo editor will also be of help.

 

The best picture for Super 9 is a photographic quality picture, which has two dominant colors:

 

 

This particular picture will work well, in that not only are there two dominant colors, they are on almost opposite sides of the color wheel. Blending of these two colors at even intensity will create pseudo-greyscale shading as well.

 

Step 1: Open this picture into your favorite photo editor, resize it to 320x192. Save it as a .PNG or .BMP

 

Step 2: You will open up two instances of G2F. Select 4x1, and 16G on the left panes, and 40 bytes width.

 

Step 3: Import the resized picture. You will tick "Resize" and "Grayscale". Choose "Standard" for your character set rendering.

 

Step 4: Save the G2F. Choose an 8+3 filename (here I used "NEBULA9A.G2F")

 

Step 5: Click the floppy disk icon in the top right to Save All Files.

 

Step 6: Import the same picture into the other instance of G2F, tick "Resize" but leave "Grayscale" unticked.

 

Step 7: Save the G2F (I used "NEBULA9B.G2F")

 

Step 8: Save All Files

 

Step 9: Look for these files: NEBULA9A.FNT NEBULA9B.FNT NEBULA9A.SCR NEBULA9B.SCR ... copy these to your emulator's hard drive folder H:

 

Step 10: Boot the attached .ATR and load the viewer program (which I have named NEBULA.TUR)

 

Step 11: Change these lines: 1019 - names of the two font files

1200 - the POKE vaules of 1070 and 1071 are for COLBK. You may need to experiment with these, but start with the values of the colors in the picture.

2002 - name of one of the screen files (doesn't matter which)

 

Step 12: Run this in Altirra with Frame Blending on, and under Video:Adjust colors, turn down your brightness and turn up your contrast.

 

That's it!

 

 

I am attaching the .ATR and the zip file with the two G2F's used to make this.

 

nebula g2f's.zip

nebula.atr

Edited June 23, 2012 by Synthpopalooza