Not only do I believe that projection causes slides to fade if projected too much, but I also think that the quality of the projected image is entirely dependent upon the quality of the projector's lens, which is probably much lower than the IQ of the lens used to take the photograph.
Light is only a problem over the long term, eg with hours of projection. There are various archival references on this.
In my experience a very good projector lens will reveal the detail in the slide, right down to the grain. Very good lenses outresolve fine grained film.
....modern ? ) had real good standard lenses (Leica pradovit a.s.o.) these companies also offered real excellent lenses in addition (higher priced). And with midt format projection (6x6 for example) there never have been bad lenses.From my point lenses of Rollei (and others) were allmost the best - money can buy - and these projectors were standarisized equiped with.Digital projection is comming better and better.But to the next 5 years it will be much more expansive in comparison. .....(If your digital projection is with 8k you can have better quality than 35mm slide today - but have you ever noticed the prices of such equipment?)With 6x6 or higher it should be the identical quality (compared with 8k).........so "analogue" projection is still "state of the art in 2018"...
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