Graphics with old C64 colors and how to view them

Continuing presenting some of the graphics I’ve done for the Commodore 64, this article revolves around my latest picture and how to view it – in technical sense.

This picture is a bit different, since it’s made for old PAL C64 with so called “old lumas”, which I covered in my previous post. In other words I’m making use of the slightly different color palette found in early C64s. And not only the palette, I’m also exploiting the color bleeding introduced by the PAL color encoding. The result is that the picture appears to be more colorful than one might expect from the 16-color palette of a C64.

This picture requires a specific hardware setup. Namely a PAL C64 with early 6569R1 VIC-II chip. A real C64 is needed, or alternatively, an emulator or viewer that can simulate the effect of PAL color encoding/decoding while supporting the old lumas. The reason is that with this picture I’m exploiting color bleeding together with the different color palette.

Screenshot taken using an emulator with old luma settings and PAL video encoding emulation.

 

Work process

Working on this piece started on Excel. I wanted to have a proper palette for the old luma colors, so I ran the same calculations that Philip “Pepto” Timmermann has made, but using the old luminance values. This way I got an old luma version of the so called pepto palette. A link to palette at the end of the post.

C64 S-Video cable – the easy way, and with no SCART

I made another C64 S-Video cable for a fellow Commodorist. Instead of using SCART, this time I made the cable as an actual S-Video lead, which admittedly is more universal than the SCART connector. Also this way it doesn’t take that much effort to make the cable.

This time I present you step-by-step instructions on how to make the thing. For more theoretical approach and details about the wirings and components, check the other post where I made the SCART cable.

I think the best and easiest way to make a cable like this is to use an ordinary S-Video and audio leads. And that’s what we’re going to do here.

Here’s what we need. An S-Video lead, an ordinary audio cable with RCA male connectors, an 8-pin DIN plug for the C64 Video port (check the other post for connector type details) and a 330 ohm resistor. Additionally you might need some heat shrinking tube, and of course, a soldering iron plus some solder, and tools for wire stripping and cutting. Not to forget a continuity tester or multimeter.

C64 A/V cable – theory and practice

A while ago I made a proper SCART cable for Amiga, so why not for C64 as well? So what I did was a C64 SCART cable with selectable composite/S-Video mode, including a ‘chroma fix’ and audio noise reduction ‘mod’ plus a preparation for possible stereo audio use. But let’s start with the theory.

Cable making principle

Building an A/V cable for C64 is not very difficult. In the simplest form, what is needed are plug for the C64 Video port, a cable with enough wires for the desired operation and the output connector(s).

C64 Video port

The C64 Video port is an 8-pin DIN connector, which is a standard multi purpose connector. It means that the required DIN plugs are easy to find and cheap. However, there are two different versions of the 8-pin DIN plug. The two versions differ in the shape of the arc that the pins form. Best shown as a picture:

The two pins marked in grey in the wrong type DIN plug will prevent the plug from being inserted into C64 A/V jack. But not to worry in case you’re holding the wrong type of plug in your hand, these two pins can be cut off or pulled out from the connector plug. In any ordinary A/V cable they are not needed anyway. Here is the Video port pinout:

Some early C64s had a 5-pin Video port that are missing the pins 6-8. It means there’s not separate chroma signal available there. In other words: no S-Video, only composite available via the video port.

Make note on the pin 8. It is either directly wired to the +5V DC line from the PSU (after the power switch) or not connected. According to my first hand research, the +5V DC line is present in the C64 Video port in all but the earliest two models. The +5V line is present starting from model C64B, or motherboard ASSY-NO. 250425. That means machines manufactured starting from 1984.

Brilliant picture from Amiga with RGB-SCART

I wanted to be able to hook up an Amiga 500 to TV with decent picture quality for an upcoming gaming session. Instead of using the lousy composhite signal or the dreadful RF antenna cable I wanted something much better because modern TVs don’t forgive low-quality video signal. In fact, flat panel TVs tend to make old systems look really bad. Low resolution and sharp, pixelled graphics (in contrary to e.g. real life video) transferred using blurry and noisy signal, and then displayed stretched and processed on a HD panel. You know it ain’t gonna be pretty! The best way to prevent the worst eyesores is to use high quality video signal at least.

So, off to make a RGB SCART cable for that Amiga.