GFX ZONE - ZX-Spectrum graphics modes

ZX-Spectrum graphics modes

by ZpiXel & GFXZone (January 2002)

The original model of the ZX-Spectrum 48K

Introduction

Back in the early eighties the 8-bit home computers were fighting a war. Looking back it is still not clear who was the winner then. Commodore and Amstrad might have ruled in Western Europe, but the Soviet Union and a part of Eastern Europe belonged to the computer which this article is about. We are talking about the Sinclair ZX-Spectrum, the ingenious invention of an englishman named Sir Clive Sinclair. The Speccy (this is how every ZX-Spectrum fan calls his beloved computer) is still a very popular demoscene machine in these parts of the world. In this article you can read about the possibilities and limitations of this machine.

Description

The first real Speccy model was released in 1982, called the ZX-Spectrum 48. It was equipped with Zilog Z80 3.5MHz central processor and 48K of RAM. There was no floppy drive or musical coprocessor - just a bunch of tapes one could load/save with his home tape-recorder and a beeper, whose sounds were rather psychotic than melodic.

The next Speccy model, the ZX-Spectrum+ was released in 1984. It differred from the previous one by an improved keyboard. Two years passed, and the Speccy was desperately fighting for its warm place under the sun. Absence of a proper sound chip or highly developed graphics system made this process more than just hard. Fortunately for all the devoted fans it lasted only untill the very end of 1985, when the new ZX-Spectrum 128 model appeared in the world of 8-bit computers. This upgraded Spectrum had doubled its RAM size and added a sound chip AY-8912 with its 3 channels and wide stereo capabilities (just like inside the Amstrad CPC). This made the ZX-Spectrum one of the most popular 8-bit home computers ever, especially in the (former) Soviet Union. The two last models of the official Spectrum family were ZX-Spectrum 2+ (1986), equipped with internal tape-recorder and ZX-Spectrum 3+ (1987) which added an internal floppy drive.

ZX computers were very simple in design and this made them easy machines to clone. Within only a few years of the initial launch, a huge number of illegal clones had been produced around the world. More clones were produced in the Soviet Union than in the rest of the world combined. This started at a time when the average monthly income was just 250 roubles a month, and an original Spectrum cost 40000 roubles - equivalent to 13 years' wages.

The most popular model of the new generation of Russian ZX-Spectrum clones was the Pentagon 128 (photo on the right). This machine was followed in the nineties by the Scorpion 256 and Kay 1024. These later models provided users with extra memory and higher processor speeds, but the Pentagon 128 keeps holding its status of the most popular ZX-Spectrum clone in Russia.

Basically, Pentagon 128 is a completely hand-made computer, and it can transform to any form. So you shouldn't be surprised when you find Pentagons in PC tower cases, with a PC keyboard and SVGA monitor. As you can see on the image on the right side of this page, a Pentagon is sometimes no more than a bunch of circuit boards and wires laying on a table!

Graphics

Even though there have been a lot of Spectrum machines developed, the graphical capabilities have not evolved as much as you might have expected. Every ZX-Spectrum has a palette of 8 colours and all of them can simultaneously be displayed on the screen. The palette is fixed, and the colours at your disposal are: black, blue, red, magenta, green, cyan, yellow and white. You can also use the brighter version of each colour by switching on the 'brightness' option while drawing. So, in practice, you can use 15 different colours on the same screen ('black' has no bright equivalent).

There is a unique limitation on the graphical capabilities of the Speccy, which gives the graphics from this platform very distinctive characteristics. The screen is divided in so-called 'symbol-places', which are pixel blocks of 8*8 pixels. Each of these blocks can contain at most 2 different colours and these colours have to be of the same brightness level! The image below shows a graphical example of this principle.

A detail of the image has been enlarged to explain the symbol places. Image by Paracels.

Unlike most other known computers the Speccy hardware does not really have a possibility to use multiple screen modes. The only one officially available is 256*192 pixels with 8/15 colours. But over the years Speccy programmers have invented a number of 'software hacked' screen modes. Unfortunately these hacked modes are not always compatible with all Speccy models, and are therefore not really popular.

One of those hacked modes is called 3colour. The idea behind 3colour is to have 3 images and display them on the screen rapidly after each other. The Spectrum has the ability to change the screen 50 times per second, so you can image that this is a rather uncomfortable mode to watch. After 5 to 10 minutes of using this mode your eyes are about ready to blow or pop out of your head! It is mostly used to view converted PC/Amiga gfx, but some editors exist that support this mode. For some reason nobody is using these editors...
Another software hacked mode is called GigaScreen (see example picture). This is a recently introduced screenmode based on the fast changing of 2 (specially prepared) images. When watching these graphics on a Speccy there is a bit of lacing involved, but it is not as nasty as with 3colour. The main advantage of this mode is that the palette is enlarged to 36 real colours! There is an editor for this mode, but unfortunately this editor is only available on PC and not on a real Speccy. Graphicians are only beginning to master this mode.

The third hacked mode is called Multicolour. Lots of different kinds of Multicolour screen modes exist, 4x4, 4x1, 8x1, etc. Unfortunately not every Spectrum model can handle them right, so every Multicolour should be tuned for a specific model! It is used in demomaking mostly to achieve colourful effects. There are a couple of editors available, but due to the mode not being standard on each model, Multicolour images are very rare.

Painting Tools As you have just read, making gfx on the Speccy isn't as easy as you might have thought before. The low resolution and small palette makes it a real challenge to create graphics. In order to take some of the burden of the graphicians, a number of painting tools have been developed. These are the ones that are most popular, including quite a few actual program screenshots. 1. Art Studio (c) - OCP (right) This is probably the oldest painting tool for Speccy, and it is still popular among some graphicians. It was made by the English OCP company in 1986 and has almost all the features one may need while drawing. Besides a version that runs on the Spectrum, Art Studio is also available for other 8bit platforms like the Amstrad CPC and the Commodore 64.

		2. Burial Graphics Editor (c) - Delirium Tremens (left) Unlike the old Art Studio, this tool is very recent and still in development. It includes lots of useful features that Art Studio does not have. Recently version 3 of this tool was released and most graphicians use this tool nowadays. The screenshots on your left are from the Russian version of this tool, so you can test your skills in the Russian language. The image shown in the editor is Prisoner of time by Pheel. The sourcecode of BGE is openly available. 3. Excess Deluxe Paint (c) - Excess Team (right) This painting tool used to be the main rival of the Burial Graphics Editor, but unfortunately for the Speccy scene its development has stopped. It has a number of features which the Burial editor does not have. Since EDP is no longer developed, BGE rules the party, so to say. In the screenshots on your right an image called Polar Star by Diver has been used.

ZX-Spectrum Graphics Scene As with any computer Speccy has its own graphics scene, graphicians and such. There are many demoparties whose gfx competitions attract lots of major (and yet beginning) graphicians. The most popular parties are Chaos Constructions, Phat, Paradox, Forever & Millennium. Some virtual graphics competitions are also held for ZX-Spectrum, e.g. Final Shoque, Nuotrauka and Millennium (the other one). Recently the ZX scene got its first website dedicated to Speccy graphics, called ZpiXel. The design for this site was based on the design of the GFXZone.
		People say the Spectrum graphics scene is a copy of the PC/Amiga scene. And as you can see by looking at the scenecopy image created from Meatpuppies by Nero, this statement has a bit of truth indeed. But, as every scene platform, ZX-Spectrum has its own marvelous pieces of pixel art. So if this article got you interested, you should visit the special GFXZone theme gallery devoted to Speccy graphics.

This article has been a coop between Paracels/Placebo and NdK/GFXZone, with some added support in the form of screenshots and photos from DMan/Placebo. If you are looking for more information or a good place to start if you are interested in the Speccy scene, then you should visit Scenergy. Unfortunately most of this site is in Russian. The ZpiXel website focusses on Speccy scenegraphics and has english news. Technical details of the original series of Spectrums can be found on The speccy zone

Visit our ZX-Spectrum gallery and send us your Speccy graphics.

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