Several attempts had been made in the 1950s and early 60s at making audio tape accessible to the casual home user, including a commercially disastrous (but technically impressive) cartridge system from RCA in the US in 1958. Dutch firm Philips introduced the Compact Cassette in 1964 and, whilst slow to get taken up by the music industry, taken up it eventually was and in 1966, EMI began to release albums on pre-recorded "musicassettes".
EMI launched their first batch of "musicassette" releases in August 1966, packaged in plastic Norelco cases into which were tucked a folded "J-card" - later referred to as the "inlay". This contained a rectangular representation of the cover artwork along with tracklistings and a portion of the album sleevenotes on the reverse.
Tapes distributed during this launch period included a small promotional leaflet (shown above) listing all the available titles at the time.
The inlay spines all carried this
1⅞ ips logo, referring to the speed
at which the tape was designed to play.
For the first two or three years, cassettes continued to use the terminology previously associated with open-reel tape - i.e. referring to each side as 'tracks'. In fact, this was a misnoma because each side of a stereo cassette has two tracks, so the two sides actually total four tracks.
So to be correct, Side 1's songs should have been headed 'Tracks 1 & 2' and Side 2's songs, 'Tracks 3 & 4'!
During 1966, EMI's cassette labels were pale blue as in the Eartha Kitt example (above left). In 1967 they switched to a very CBS-like orange, then between 1968 and late 1969 lime-green labels were used, until finally various shades of yellow and yellowy-green were used from 1970 to 1973.
EMI product manufactured before the Summer of 1969 carried the message "SOLD IN U.K. SUBJECT TO RESALE PRICE CONDITIONS. SEE PRICE LIST." A few of the earliest cassettes only showed this message on the inlay, but was added shortly afterwards in the corner of the cassette labels themselves.
Around the same time, the typeface changed from the Futura Condensed Bold used on the earliest tapes, to the Compacta variant so commonly used on LP labels during the 1960s and 70s.
A feature of EMI cassette inlays from 1966-68 was that they weren't printed in full colour - not even for the front cover. Instead, a single 'key colour' was chosen (pink, as in this Shadows example) to apply as a background colour to the title area and as a tint to the photographic elements of the artwork.
The vinyl edition of this album showed the band members' faces in full colour within the jigsaw pieces.
Finally, it's worth noting that tapes of this period all had a standard EMI box logo shown in the top-right-hand corner on the front (or Tamla Motown logo for their releases).
As shown below, these features would later be dropped.
So in 1969, a few subtle changes were brought about to EMI's inlay layouts. Firstly, front cover images were shown in full colour as standard (as occasionally had been done for complex cover imagery such as The Beatles' Sgt. Pepper a year earlier on its 1968 tape release).
Secondly, it was decided to show the artist and title in plain black text on a white background, instead of using colours and typography in the style of the vinyl sleeve as done previously - perhaps at the time this was considered too much hard work. Also, the decision was taken not to show the EMI (or other) logo on the front as a standard design trait.
During 1969 the inside-flip continued to be used as a space for artwork or sleeve notes, whereas in 1970 this area would be conscripted for advertising other cassette releases. Also in 1969 a new international numbering system was adopted by EMI worldwide (excepting Capitol in the US) and both the UK and international catalogue numbers were shown in the white space of the inside flip (further explanation of the '1E' number is given on the next page).
Tracklistings continued to be displayed as full spreads over the reverse face of the inlays. It was on this side, on the back flip, that the black-box EMI and label logos now appeared.
As cassette covers are rectangular but vinyl sleeves are square, there had always been a compromise necessary in deciding how to best present the original artwork in a form compatible with the space available. Also, it appears that with EMI stepping-up cassette releases to match a similar release schedule as vinyl albums, it was no longer considered viable for each title to receive particular 're-design' effort for tape as had happened from 1966-68.
During 1967-69, the 'inside flip' (the panel shown to the right of the front cover on these fold-outs) was used either to include additional artwork, or (as in these Motown examples) to include sleeve notes.
This meant the full tracklistings and credits ended up being printed on the reverse face of the inlays, occupying a full spread across the two adjacent panels.