FFRR and FFSS

I bought 2 Decca record in a junk store. Both of them are conducted by Mantovani. One of them is an album of Christmas with ffrr on jacket and cover. while another one an album of movie song theme with ffss label on jacket and cover.
When I listen to both of them, they sounds very similar. So is the difference between ffrr and ffss?

Personally, I've never seen the ffss, but this is what wiki says about ffrr-

FFRR (full frequency range recording) was a spin-off of Decca

I have a question related to this: why do English Decca and London (and related) labels have the master numbers printed upside-down on the labels? I see this on albums dating well into the 1960s.

So they are! I hadn't noticed that before. I checked my 78's, and it looks like they didn't start doing it on them until about 57 or 58.(or at least on the few I could lay my hands on for now) I can't get to my vinyl's at the moment to check them though. They weren't doing it on the Australian pressings. Perhaps someone from the UK might have the answer??

Maybe the numbers are right-side-up to the Aussies and upside-down to the rest of us?
(just kidding, of course - I love Oz and I'd love to visit the country someday!)

LOL. They reckon our water goes down the drain backwards, so I guess anythings posible

ffrr is Full Frequency Range Reproduction

ffss is Full Frequency Stereo Sound

The original ffrr was a change in the way a 78 rpm record was recorded. Originally, 78 records recorded electronically (electrically) were recorded flat, except that the bass was rolled off at 6 dB/octave below the 250 Hz turnover frequency. The ffrr process added a treble boost of 3 dB/octave above 2500 Hz, reaching 6 dB at 10 KHz, so the treble recorded is better. A complementary playback curve was needed, so Decca records needed a different playback curves, compared to the standard record in 1937. This led to the introduction of a tone control.

In the early 1950s, English Decca created a pre-emphasis curve that was unlike any other company's curve. It is often called the London curve, since London is the label English Decca uses in the US. The turnover frequency is 500 Hz, and the bass cut stops at 100 Hz to improve play in the rumble region. The treble boost is a 6 dB/octave boost reaching 10.5 dB at 10 KHz.

In 1955, English Decca adopted the RIAA curve, called the "new London" or "new ffrr" curve. This has a 500 Hz turnover, with a 50 Hz bass cut stop, and a 13.7 dB boost at 10 KHz, at 6 dB/octave.

In 1958, the stereo groove was added. ffss was used to denote a stereo record when records were sold in dual stereo and mono inventories.

I used to work at a used-record store and spent weeks organizing the "Contemporary" section. We had copies of Mantovani's albums coming out the ying-yang and I got actually sick of seeing that name and the London label (I had to check condition, too). On a lark I brought home one of the albums and was absolutely blown away by the sound...fantastic. Mine was an "ffss" copy, by the way.
And whoever worked at London in the Graphics Dept. must've had a sense of humor - if you look at the album cover just right, you'd swear the name of the album was really "Stop The World, I Want To Get Off Oliver!"

HE HE! I've got that record... and you're right!