I was staggered at Zone 5’s attitude. Anyone can make the boo-boo of not rinsing the slides enough (but they are “professionals”) but they seemed determined to waste my time.
The truth is that professionals do not shoot 35mm film any more and if you’re not doing two thousand US a month in medium format with them they don’t want to know you. That’s the impression I get from Jazz, too. But Jazz have done a fair bit of stuff for me recently and always done it right.
Frankly, if the wee man on the corner did E6 I’d use him just as quick as any of these so-called “professionals”.
And Jazz had Velvia 100 (RVP 100) last month when it came out and Zone 5 had never heard of it. Yaa Boo.
Edit: negatives are almost always printed by a machine which auto-exposes and auto-colourifies the prints making it all a bit of a lottery. I stopped shooting them years ago not because I’m any good at taking photos or some sort of an expert, but because I could find nowhere which would make nice prints. Likely the same in Taiwan. So I shoot Fuji slide film, Velvia or Provia. I’ve had very good results with this approach (except for my complaint noted above) and Jazz will still expose slides onto photographic paper by hand (rather expensive).
I advise shooting several test rolls and assessing the labs yourself. That’s what I did, rather than risk important stuff when you don’t know what they’re like. (Slides only cost about NT$70-odd a roll to process and mount so it’s not as expensive as it sounds.)