From 16.7 million to 16 colours in no time at all

Fab Four GMT standards, Greater Manchester Museum of Transport
The original image taken by myself in jpeg mode.

Next year will see the 30th anniversary since the launch of the Commodore 64 computer. For most persons within their mid-20s to early 50s, the Commodore 64 is often celebrated for its games software and the SID chip.

Though today’s computers have multicolour graphics, more than eight hardware sprites on screen at any one time and far more than 64k of memory, there are some people who yearn for the era of 8 bit computing. In spite of the time it took to load a game, Magicland Dizzy, Monty on the Run and Hungry Horace still brings back a lot of memories.

The Tutorial:

My chosen software weapon of choice is the cheap and cheerful photo editing package The GIMP. Therefore, this could be practiced on a Windows PC, Mac or a PC with your favoured Linux distro.

You Will Need:

  • A Linux/Windows PC or a Mac;
  • A copy of The GIMP installed on any of the following systems;
  • A photograph of your choice to experiment with;
  • A love of all things 8 Bit Computing, particularly Commodore 64s.
Estimated completion time: 30 to 60 minutes (dependent on fluency with The GIMP and speed of machine).

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Part One: C64 Style Pixellation Effects:

1. Open GIMP as normal from your personal computer of choice then choose an image to work with. Do so by moving your mouse to File then Open (or press CTRL+O) and choose your file. Click ‘OK’ and let The GIMP.

2. Reduce your image by clicking your mouse on the Image menu and moving it down to Scale Image.

3. You should see a box with width and height dimensions and a chain link between the two dimensions. Reduce the width to 320 or the height to 200. Click OK.

4. If the image exceeds 320 x 200 (i.e 320 x 256 or 343 x 200), crop it using the Crop tool on the left menu so that it is exactly 320 x 200 pixels.

5. Reduce the image to 160 x 200, again in the Scale Image box. This time, break the chain by clicking the chain link so that the height remains 200 pixels.

5. Repeat Steps 2 and 3, but change the width to 320 pixels. At the bottom of the box you should see a section named ‘Quality’ and a pull down menu for interpolation options. Click on the box and select ‘None’. Click OK.

6. We are halfway through the C64-isation of our image. At the moment, there are still 16.7 million colours in use, not reflecting the C64’s palette. Our next part remedies this issue.

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Part Two: Adding a Commodore 64 Palette to The GIMP:

1. Click Windows and move your mouse to the Dockable Dialogs menu then move it towards the Palettes option and click Palettes. A selection box of preset palettes should emerge.

2. Drag the Palettes box to the right hand side menu box then click on the New Palette icon (denoted by a spare sheet of paper in a circle). The Palette Editor box should open. Name your palette Commodore 64/CBM 64/C64 (or anything else which symbolises Jack Tramiel’s wonder machine).

3. Double click the fourth icon at the bottom of your Palette Editor box (our friend the Sheet of Paper in a Circular Icon again). You should see inside the centre of this box your default foreground colour (often black).

4. If it isn’t black, click the third icon at the bottom (a pencil and paper) to edit the colour. The Edit Palette Color box should emerge. Go to the HTML notation box and enter 000000, the hexadecimal code for black.

5. Click the fourth icon at the bottom 15 times to allow for the inclusion of the Commodore 64’s other 15 colours.

6. Select the Columns box above the small icons and choose 1. You should see 15 more instances of black more clearly in the centre of your Palette Editor window. Click on the box directly below the first colour and enter ffffff, the values for white in the HTML notation box.

7. Repeat the above step by entering the following values into the HTML notation box:

  • 68372B: Red;
  • 70A4B2: Cyan;
  • 6F3D86: Purple;
  • 588D43: Green;
  • 352879: Blue;
  • B8C76F: Yellow;
  • 6F4F25: Orange;
  • 433900: Brown;
  • 9A6759: Light Red;
  • 444444: Dark Grey;
  • 6C6C6C: Grey;
  • 9AD284: Light Green;
  • 6C5EB5: Light Blue;
  • 959595: Light Grey.

Then click OK on the Edit Palette Color box to confirm your changes.

8. Save your palette by clicking the 3.5 inch disc icon at the bottom left of your Palette Editor box.

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Part Three: Finishing Touches:

By now, you should be minutes away from turning your high resolution landscape into something from the Commodore 64 era. Thanks to the wonders of modern technology, we no longer need to save our works on a Datasette or a 1541 5.25 inch floppy drive. We can also show our C64 style masterpieces off to unsuspecting persons on Facebook, Flickr and the like.

The fun bit starts now.

1. Click on the Image menu, moving your mouse to Mode. Follow the arrow to unveil another menu and select Indexed.

2. Another box entitled Indexed Color Conversion should emerge. Look for a menu entitled Colormap and click the button left of Choose Custom Palette. Click on the thumbnail image which shows the palette. From your list of palettes, choose your recently saved Commodore 64 inspired palette (entitled C64 palette, Commodore 64 or the like of course).

3. Below, you should see another menu for Dithering. On the pull down menu for Color Dithering, choose None. Then click the Enable Dithering of Transparency box and click the Convert button.

4. Your image (or images) should be C64-ified. Lovely Jubbly! Save your work as normal (I recommend saving your C64-esque image in PNG format). Then start sharing them with other like-minded, or not-so-like-minded people. Here’s how it should look, having converted one of my bus pictures into a C64 image. Enjoy!

The converted image, gloriously transformed from a jpeg file to a Commodore 64 style image saved as a png file.

S.V., 03 December 2011.

2 thoughts on “How to Convert your Photos into Commodore 64 Mode

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