Answer: I used a PhotoLab (mostly)
I've only just recently completed sorting the batches of negatives that I had scanned for me, back in 2012, by Boots in the UK, a high street/town centre chain store, primary business is pharmacy but they have an established photo department in their stores. I've come back on this site to close this question with this as an accepted answer.
Their equipment is not exclusive, it's a Fujifilm SLP1000SE minilab, accoring the EXIF data in the images on the CDs that came back from the processing which I think other stores, such as Asda use.
The results are rich vibrant and colourful, balanced and crisp and good dynamic range to my eyes, without sounding like a cheesy promotion (I don't work for any of these companies). The image resolution is the equivalent of 2 megapixels which by today's standards is rather low, but this does not concern me for 2 reasons: the photos were mainly taken on a Olympus MJU compact film camera and a Canon DSLR entry level camera in the 1990s-2000s. Both are decent cameras but the film grain is perhaps slighly larger than the pixels. Second reason is that by the early 2000s 2 megapixel cameras were affordable so I would not be gaining given the fact that higher resolution wasn't available. This specification may vary with PhotoLab/shop.
All this stands up well to a cheap "Traveller"-brand USB manual slider negative scanner from Lidl or Aldi cut-price supermarket, if I recall, where the dynamic range is less so with a slight red tinge. So this point answers my original question.
I had about 50 negative rolls, each either up to 24 or 36 shots, so would have been a daunting soul destroying task to do manually, perhaps. The scanning shop mentioned above did these in the space of a week as they offer a say turn around and in some cases on the day or within a few hours. They generally offer 1 hour service, but with the volume I had, I did this in batches and it was understandable that they wouldn't be able to do them all in 1 hour.
Even though this was very quick, there is still time required to check through the results. I didn't want to keep the negatives or the original photos so had to spend time comparing the digital results with the negatives (only briefly held up to the light) and the original photographs. Depends on how OCD you are on this. For me this was part of my ongoing activity to declutter.
Let me share some learnings with you:
- be methodical and realistic about the time you will spend checking (if you want to) the digital versions that you get back.
- If you have a lot, understand that you will have to do this over several sessions if you have a full time job commitment, family, pursuits etc. After each session, note where you were at to pick up for next time. This is a mistake I made where I didn't track my progress after each session and did spend a bit of time on the next session going over what I did before.
- If you are unsure of the shop, have a non-valuable set of negatives done first to "test-the-water", that's what I did.
- Then if you are happy, you might want to try to have as many done as possible in a large batch onto one media. I say this because in my situation, I got a CD back for each 24/36 roll of film, about 50 CDs. This has now been condense onto one DVD-ROM data disk. The CDs have been cut-through and sent to a CD recycler which melts them down and uses them to make low grade mouldings for various purposes.
- If you get in a muddle about what files are which, BeyondCompare and Fast Duplicate File Finder can help. BeyondCompare was great for checking copies I put on the DVD-ROM against the original CDs, before destroying them.
- When I said "I used a PhotoLab" mostly, it was because the PhotoLab/shop did miss about around up to 3% of photos. Sympathetically, I put that down to natural human error in the shear volume of negatives I gave them in a short space of time. The remedy here was either to use the USB hand scanner or for better results I found the DoxieGo portable scanner gave similar quality to the PhotoLab- I use this for scanning in paper documents usually, to be able to discard them.
- It's important to note beforehand what you give the PhotoLab in case of any disputes over what might be lost. I didn't have this issue. Tip: you may find with your original photos that the processor also gave an extra 'photo' with thumbnails of the negative roll. Keep this and use as proof as to what you submitted.
Overall, it's worth paying someone to do the work for you for a large quantity: spend money to save time. Though for me this did run into 100s of pounds, but meant I had time for other things in life. I would recommend who I went with in the UK, but I have pointed out other options and would say again, I don't work for any of these companies.
As well as high-street/town centre shops, there are specialist businesses that will also do the job and do it very well, that I know of, just search online or checkout your local business directories or advertising papers or local press.
Finally I would credit everyone else who has answered here, their thoughts are useful for your consideration.