...I suppose the only other thing that I'm unclear about is the SET SANE_DEFAULT_DEVICE=libusb:001:001 statement. This does work here, however TAME still references the 'hp' backend and indeed the CLI it executes still uses that as well, namely:
Start: 10 Jan 2021 00:43:52
Job: Scan to file
Command1: START /MIN /C SCANIMAGE.EXE -d hp --resolution 1200 --format=tiff -l 0 -t 0 -x 215 -y 296 > G:\tmp\scanner\Image025.tif
File: G:\tmp\scanner\Image025.tif (17764970 bytes)
End: 10 Jan 2021 00:46:36
For consistency's sake it's worth adjusting this in TAME, which is what I will test out next.
...
Quick test this was.
No-Go, the 'hp' (in my case) is baked into TAME, I assume through it's scanner list database. So this is actually a non-editable field and is auto-populated once you select the scanner.
Sooo, '-d hp' still works, TAME is happy. Meanwhile the current
SET SANE_DEFAULT_DEVICE=libusb:001:001 statement needed a small change. I found multiple on-line references to Linux style mappings, such as:
1) SANE_DEFAULT_DEVICE="hp:/dev/scanner"
2) SANE_DEFAULT_DEVICE="plustek:libusb:002:002"
In the end, relying on Wim's earlier post and using his quick CMD as a template (Thank You Wim!) I was able to whip-up a working setup where the correct value is: "SET SANE_DEFAULT_DEVICE=hp:libusb:001:001".
Here is what that looks like when the following scanimage CLI is executed "g:\usr\bin\scanimage -v 1>\tmp\scanner\scanner_scan.pnm 2>\tmp\scanner\scanner_scan.txt":
[sanei_debug] Setting debug level of dll to 4.
[dll] sane_init: SANE dll backend version 1.0.13 from sane-backends 1.0.28
[dll] sane_init/read_dlld: attempting to open directory `g:\etc\sane.d/dll.d'
[dll] sane_init/read_dlld: using config directory `g:\etc\sane.d/dll.d'
[dll] add_backend: adding backend `hp'
Output format is not set, using pnm as a default.
[dll] sane_open: trying to open `hp:libusb:001:001'
[dll] load: searching backend `hp' in `/@unixroot/usr/lib/sane'
[dll] load: trying to load `/@unixroot/usr/lib/sane/hp1.dll'
[dll] load: dlopen()ing `/@unixroot/usr/lib/sane/hp1.dll'
[dll] init: initializing backend `hp'
...
One can tell how the 'hp' backend is successfully resolved.
EDIT
====
Has anyone taken over the TAME maintenance? I think Paul has released the SANE updates in the past, may have been packaged together actually...it's been a while.
The reason I ask, there are some changes in the past backends and the latest one we have today (1.0.28), specifically for my 'hp' backend the 'grayscale' setting is no longer valid, instead it would appear that was replaced by 'gray'.
A quick look at the TAME INI file shows some of these being stored, but I haven't quite figured out how these map to the actual SANE commands TAME uses, is this hard-coded?