The history of "softcore"

Over lunch recently, my colleagues and I were discussing the term "hardcore," and speculating on its origin. Our speculations evolved into "What has either a hard or soft core, where the hard cored thing would be used by professionals and the soft cored one by amateurs?" because this is where we figured the terms originated.

Following this discussion, I did some research and found that the origins of hardcore (by way of Etymology Online) are most likely from the original definition of hardcore:

material such as stones and broken bricks used as the foundation for buildings, roads etc.

rather than having to do with a fruit or ball as our lunch group had envisioned. The foundation connotation is presumably the important connection between these usages.

However, looking into softcore has produced less satisfactory results. I found this description from 1875, which explains hard-core and soft-core and says that soft-core is essentially compostable garbage. What I don't understand is how this word came to be associated with its current, more familiar meaning, which is as a milder or watered down version of "hardcore."

Given their relationship, I expected there to be a more explicit connection between the two. For instance, that soft-core was a layer applied after hard-core or that inferior roads used soft-core instead of hard-core, but that doesn't seem to be the case. What is the connection here?

From the comments to the OP:

My understanding of the terms "hardcore" and "softcore" come from baseball and softball, and the term "hardcore" at least is roughly synonymous with "playing hardball" which is definitely baseball-related.

More in-depth: Since the early 1900s at least, baseball has been played with the eponymous cork-cored, twine-wrapped, leather-skinned sphere that has near-universal recognition. The only significant change to the "official" baseball used in the major leagues was during WWII when rubber was substituted as the core material to replace cork (which was needed for the war effort). Cork baseballs are small, dense, and not very forgiving; in fact, players have died from head trauma after being "beaned" and been forced to retire after making barehanded catches that shattered every bone in their hand. Such a ball is a "hardball", and playing with it is "hardcore baseball".

The game of softball is not that much newer (1887 vs 1845 for baseball), but it evolved from the game we have come to know as baseball to create a more "casual" game. The name "softball" came from the original construction of softballs; primarily similar to baseballs, but much larger (up to 16" in circumference) and more loosely wound. As the early balls broke in, they really did become soft, and the game was actually originally intended to be played barehanded (thus requiring virtually no individual equipment; just one bat, one ball, and some base markers). Modern softballs are not very soft, and so the modern game is played with gloves (and "fast-pitch" leagues for women use practically all the same gear as men's baseball leagues with the primary exception of "pelvic protectors" replacing athletic cups), but the balls still "give" more than cork baseballs, and more often incorporate softer core materials such as rubber.

The two games have both been around long enough in recognizable forms, along with the eponymous balls used to play them, to be the origins of the terms. My thoughts are that "hardcore" came first, and then "softcore" followed as a complementary antonym. Unfortunately the sexual connotation the terms have gained makes it difficult to do real research into the terms themselves from a work computer. I know the term "hardcore" has been commonly used figuratively since at least the Vietnam War.

Hardcore

There are three definitions in the OED that show the progression of hardcore.

First, hard-core is the rough bits of stuff used as building foundations, with a quote from 1851:

The phrase ‘hard-core’ seems strictly to mean all such refuse matter as will admit of being used as the foundation of roads, buildings, &c.

Next, this tough centre is applied to people and things:

an irreducible nucleus or residuum; also a stubborn or reactionary minority; something blatant or intractable

First quoted in 1936:

Possibly 200,000 would be practically unemployable on any ordinary basis—the ‘hard core’ as it is called.

And we can see the meaning change in these more recent quotes:

• 1959: A work of literature‥stands on quite a different footing from hard core pornography.
• 1968: Heathrow airport‥could, perhaps, be called the hard core of Britain's noise problem.
• 1973: The leading modern writer of hard-core science fiction.

Finally, it's applied to punk and other forms of music:

orig. U.S., (a) adj. denoting harsh, aggressive, or extreme versions of various types of popular music (originally punk, now also rap, techno, etc.), typically faster, louder, or more experimental than related forms, and determinedly less mainstream; (b) n. any of various forms of popular music (often a variety of an established genre) regarded as particularly extreme, aggressive, or experimental.

First quotes:

1977: They [sc. Rough Trade] are now trading in the best reggae records that can be found as well as the hardest core hard core glue stained sounds of the new wave.

1981: Predictably, the Los Angeles hardcore punk audience is beginning to have its doubts about X now that the group has performed on network television.

Softcore

Softcore, then, is simply a softer version of hardcore, used in analogy. The OED defines it:

n. [after hard-core (pornography ): see hard core adj. and n. at hard adj. and n. Additions] attrib. (of pornography) less obscene than hard-core pornography; also absol.

Their first four quotations from 1966, 1971, 1973 and 1977 are all related to pornography. Here's the first:

The soft-core pornography of advertisements like ‘Have you had any lately?’

By 1979 it's used elsewhere:

The soft-core entertainment end of the television spectrum.

In 1964 Paul Krassner's 'The Realist' Magazine started to run a feature called "soft-core pornography," usually photographs from the mainstream media that could be interpreted in a sexual manner, most famously the August 1967 issue featuring Ronald Reagan.

Krassner has stated that he derived the term from creating an opposite to the Supreme Court use of the term "hard core" in reference to Pornography.

See http://www.ep.tc/realist/76/13.html

I have only a few references, but I do want to point out that nominal meaning of the words can adequately explain the genesis:

• hard core: if at the core, or the inside (or fig. essence), something (or someone) is hard (resilient, strong, durable) we say they are "hard core" or "hard-core" and we mean that they are "stubbornly resistant" or "die-hard" (from here)

• similarly, soft core as antonym gives back meaning to hard core: let's take the

  material such as stones and broken bricks used as the foundation for buildings, roads etc. (also technical, but trivial nature was confirmed when I looked at ngrams and followed to books; actually I found references to electrical engineering¹)

So, hard core would make something "stubbornly resistant" compared to if the foundations were filled with any rubble that was in essence soft (this would occur). In this sense I am sure that things that had a soft core would break quickly.

¹ Soft and hard core of wires would make them rigid or soft, too.