The series issued in 1991 is printed with a four colour technique.
Which results in very colourful and detailed packets.
The series were issued several times, with small differences between them.
The numbers are not identical. And some numbers are not printed at all.
Below information I have copied from the Valk-book from P.C. Korteweg.
He makes 5 series:
I On the front, the towns name is Bold.
II On the front, the towns name is Thin. On the back,
Restaurant bedrijven is Small
III On the front, the towns name is Thin, On the back,
Restaurant bedrijven is Big.
IV The Same as I, but the bird has an orange Beak
V The paper is mat, not bright.
Numbers on the packets:
IV & V Same numbers as I