Do you also collect traffic lights?

Collecting 'gutter pairs', or pairs of stamps with a blank strip in between, has been done for a very long time. The first Dutch postage stamps were printed in 1852 in four blocks of 25 on a single sheet, allowing people to obtain pairs with a white strip in between. In Great Britain, this method of stamp collecting is a popular pastime. The gutters, as they are also called, are therefore included in British stamp catalogues, such as that of Stanley Gibbons. It becomes even more enjoyable when technical notes appear on the spacers. These can be all kinds of things, such as an issue date, just a color bar, or a barcode. However, collectors primarily look for mentions of the printing colors used in the production of the stamps.These printing colors appear on the sheet margins of the stamps or on the interstrip. And because of the format of the printing colors, in the form of large dots surrounded by a frame, they soon acquired the name 'traffic lights'. The number of dots indicates how many colors were used. In the example of the birds, no fewer than eight colors were used; for the stone bridge, four colors. The publisher of stamp articles, Stanley Gibbons, produced a color chart to name the colors used for the stamps. By placing the cutout on the dot, one could read which color had been used. The colors of the £1 were yellow-green and blackish olive-green, and those of the £5 were salmon-colored and chalky blue. Difficult descriptions! The colors were called PMS colors. The abbreviation PMS stands for Pantone Matching System, published in 1963 by the company Pantone. By indicating the desired color with a PMS number, designers and printers could coordinate this very well. Later, the printing colors were simplified by using only the four basic colors to obtain various shades. These were yellow, magenta, cyan, and black. If it was still desired to add a color that deviated, this could be done by applying a separate printing pass, as can be seen on the two stamps of 56p and 90p. An extra yellow in a slightly lighter shade. But whether the strips of five stamps were also printed with the four basic colors? I can't tell. Can you? Yet another extra dimension to collecting British stamps.