"Dirty Dancing" was structured as a negative pickup

In my previous article, Vestron's Gamble, I pointed out the following passages (emphasis added):

.... independents like Vestron depend on acquiring other people's movies. They have been forced to pay more and more money to grab the remaining few independent "A" titles, laying out huge up-front guarantees against future royalties of (usually) 20 percent.

[.....]

Vestron's first fully financed picture (structured as a negative pickup), the $6 million Dirty Dancing, turned out so well that ....

I have only a pedestrian understanding of movie financing.

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I do not know if the royalties are on the gross or on the net. However, since the production costs have become only a tiny part of the movie's gross earnings, the gross and net are essentially the same.

For the sake of easy arithmetic, let's suppose that Dirty Dancing has earned $100 million. If so, then Vestron (or whoever bought Vestron) earned $20 million in royalties. Then someone else -- mostly Linda Gottlieb? -- earned the other $80 million.

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The Lawyers.com website defines a "negative pickup" in entertainment law as follows:

Negative pickup means a distributor’s guarantee or agreement to pay a specified amount for distribution rights upon delivery of a completed film negative by a stipulated date. The distributor has no obligation to license the film if the picture is not delivered on time and in accordance with the terms of the agreement. A negative pickup guarantee may be used as a collateral security to obtain a bank loan in order to meet the production expenses of a movie.

The Wikipedia article about a negative pickup includes the following passages.

In film production, a negative pickup is a contract entered into by an independent producer and a movie studio conglomerate wherein the studio agrees to purchase the movie from the producer at a given date and for a fixed sum. Depending on whether the studio pays part or all of the cost of the film, the studio will receive the rights (theatrical, television, home entertainment) domestic and/or international to the film, with net profits split between the producer and the studio.

In the case of Dirty Dancing, I suppose that Gottlieb fits the above definition as the "independent producer" and Vestron fits as the "movie studio conglomerate". (However, maybe it's just the opposite.)

If I am supposing correctly, the split of net profits was 80% for Gottlieb and 20% for Vestron.

The Wikipedia article continues.

The word "negative" in this context can be confusing because it does not relate to a numerical value (where negative means less than zero), but instead comes from the pre-digital era in which a motion picture was embodied in physical film negatives.

By selling the rights to distribute the film in territories not covered in the negative pickup ("pre-selling") or making other deals collateral to the production, a producer will usually cover all their costs and make a small profit before production has begun. But financing of the production up to its completion date is the responsibility of the producer—if the film goes over budget, the producer must pay the difference themselves or go back to the studio and renegotiate the deal. This happened on the films Superman, The Empire Strikes Back, Never Say Never Again, The Thief and the Cobbler, and Lone Survivor.

Most negative pickup contracts, either from motion picture studios or television networks, are bankable at pretty much dollar for dollar (less fees); if one holds a negative pickup contract, one essentially holds a cheque from the studio for the cost of the film, post-dated to the day one delivers the film to them. So, while the studio technically does not pay the producer until the film negative is officially delivered (thus "negative pickup"), the producer can nonetheless get a bank loan against a negative pickup contract, which helps them to pay for production of the film.

Studios, on the other hand, typically do not like their contracts being factored at banks or shopped around to independent investors and financiers, as this ultimately gives the producer significant creative latitude over the production. With the money assured, a producer has a free hand to make the film however they please, and they are only answerable to their investors, which in this scenario are unknown to the studio at the time of the contract. If creative disagreements arise between the studio and the producer, the studio has little contractual recourse as long as the film meets certain general contractual requirements, such as duration and technical quality.

An example of this is Terry Gilliam's Brazil, a negative pickup for Universal Pictures produced by Arnon Milchan. In this particular case, the studio had creative disagreements with the director over choice of star, content, and duration, and failed to resolve these issues to its satisfaction, because the negative pickup had essentially granted Milchan final cut.

The studios and distributors will contain this risk by offering the negative pickup contract only to a production that has financiers, a script, and key creative personnel, particularly the director and stars, already attached. Thus the conundrum: unless a film has U.S. distribution, a lot of investors and foreign buyers will not pre-buy a film, and unless the film is already financed, the studios do not want to guarantee distribution. This catch-22 is often resolved by attaching a major actor to the film; the mere appearance of an American movie star's name on a film's poster is often enough to drive box office to cover distribution in many foreign markets.

If someone can explain these clues about the financing of Dirty Dancing, then please do so.