Goofy question for Ilford Expert(s)

[wogster]

Just wondering something:

When Ilford move from FP3 the next generation was FP4, similarly HP3 became HP4 and then HP5. So why was the next generation called FP4+ instead of FP5, and HP5 became HP5+ instead of HP6?

Perhaps Simon or one of the other Ilford experts knows why....

Been wondering this since getting back into photography...

 

[PHOTOTONE]

I think the transition to the + versions of FP4 and HP5 were improvements that didn't affect the ISO rating of the film.

 

[cmacd123]

I think the transition to the + versions of FP4 and HP5 were improvements that didn't affect the ISO rating of the film.

but HP4 was ISO 400 also was it not?

 

[wogster]

but HP4 was ISO 400 also was it not?

Apparently HP3 started at 125ASA, as H.P.3. then moved to 200ASA then 400ASA (still called HP3) then became HP4 then HP5 and now HP5+, still wondering why it isn't HP6?