Alright guys, this is for anyone interested, something I whipped together to start experimenting on, I've made my own first developer as a test, this was the 2nd test, and the first with success (of some measure). Just to show that aged/fogged slide film isn't necessarily useless and irrecoverable. I had made several attempts before this with latent image bleaching techniques, and bleaching post first development but pre colour development among things, so far this has been the most effective and simplest method, brewing my own first developer to compensate for fogged film, as I've done with colour negs. I'll just leave this pic here of the results thus far, far from happy with it (want better colour, change tone curve a bit), is a bit speed losing, and base does look like the film is very slightly aged with the lightest hint of base fogging (need more dMax) like it's been well stored instead of poorly stored. But if you can recover this much from something that badly fogged, more smaller adjustments could be made, and film that's not nearly as badly as fogged is also going to be able to get great dMax. The film is some really old Kodak EPN I found in a bulk loader.