The 'Stereo Spectrum Records' label was launched in 1958 as a sister label to the mono only Design Records (2) brand appears, too. It should be denoted as the second label.
An early ment can be found in Billboard 10th March 1958 page 11. It was not uncommon in the early stereo days to launch a separate "sister" stereo label. Similar politics at Stereo-Fidelity labels. The first stereo releases were announced October 1958.
The label was golden:
Early versions with cat# prefix SS have black and red print, denotes the Pickwick Sales Corp. company at the lower half.
The cat# prefix SDLP versions with only black print denotes the Design Spotlight Series as stated on the front cover. They commonly display the always same rear cover with copyright date 1962 - what off course is hardly always the release date. 'Design Stereo Spotlight Series' wording in the middle, while any credits are vacant.
The rear covers of the SS prefix version differs sometimes. For this reason it should be described at the release notes.
In 1965, when the 'Stereo Spectrum Records' was discontinued, you will find some version without the 'Stereo Spectrum' in the middle of the bar on top of the front cover. The new cover version with a Stereo line on top was used with the last vinyl version of Stereo Spectrum Records.
Please add the company with the tag 'Record Company' at the Lccn.
Please note that some "Stereo Spectrum" covers includes Design Records (2) vinyl with labels stating "Stereo Sonic Sound", which is actually a mono recording with false pretenses regarding it being adverted as stereo. True stereo recordings have either "SS" or "SDLP" cat# prefix on the labels, regarding them being released in a true stereo process.
Further helpful information is provided at the links, shown below. The lists there may help you to date the versions correct, because the copyright here is not always recommended as the release date.
